Merge pull request #3 from mrfaptastic/master

uptodate

.github/workflows/esp-idf_with-gfx.yml

@@ -0,0 +1,48 @@
+name: esp-idf with Adafruit GFX Library
+
+on:
+  push:
+    paths-ignore:
+      - '**.md'
+      - 'doc/**'
+  pull_request:
+    paths-ignore:
+      - '**.md'
+      - 'doc/**'
+
+jobs:
+  build:
+    name: esp-idf with Adafruit GFX
+
+    runs-on: ubuntu-latest
+
+    steps:
+    - name: Checkout repo
+      uses: actions/checkout@v4
+      with:
+        submodules: 'recursive'
+    - name: Checkout ESP32-HUB75-MatrixPanel-I2S-DMA component
+      uses: actions/checkout@v4
+      with:
+        path: 'examples/esp-idf/with-gfx/components/ESP32-HUB75-MatrixPanel-I2S-DMA'
+    - name: Checkout Adafruit-GFX-Library repo
+      uses: actions/checkout@v4
+      with:
+        repository: 'adafruit/Adafruit-GFX-Library'
+        path: 'examples/esp-idf/with-gfx/components/Adafruit-GFX-Library'
+    - name: Checkout Adafruit_BusIO repo
+      uses: actions/checkout@v4
+      with:
+        repository: 'adafruit/Adafruit_BusIO'
+        path: 'examples/esp-idf/with-gfx/components/Adafruit_BusIO'
+    - name: Checkout arduino-esp32 repo
+      uses: actions/checkout@v4
+      with:
+        repository: 'espressif/arduino-esp32'
+        path: 'examples/esp-idf/with-gfx/components/arduino'
+    - name: esp-idf build
+      uses: espressif/esp-idf-ci-action@v1
+      with:
+        esp_idf_version: v4.4.4
+        target: esp32
+        path: 'examples/esp-idf/with-gfx'

.github/workflows/esp-idf_without-gfx.yml

@@ -0,0 +1,33 @@
+name: esp-idf without Adafruit GFX Library
+
+on:
+  push:
+    paths-ignore:
+      - '**.md'
+      - 'doc/**'
+  pull_request:
+    paths-ignore:
+      - '**.md'
+      - 'doc/**'
+
+jobs:
+  build:
+    name: esp-idf without Adafruit GFX
+
+    runs-on: ubuntu-latest
+
+    steps:
+    - name: Checkout repo
+      uses: actions/checkout@v4
+      with:
+        submodules: 'recursive'
+    - name: Checkout ESP32-HUB75-MatrixPanel-I2S-DMA component
+      uses: actions/checkout@v4
+      with:
+        path: 'examples/esp-idf/without-gfx/components/ESP32-HUB75-MatrixPanel-I2S-DMA'
+    - name: esp-idf build
+      uses: espressif/esp-idf-ci-action@v1
+      with:
+        esp_idf_version: v4.4
+        target: esp32
+        path: 'examples/esp-idf/without-gfx'

.github/workflows/pio_build.yml

@@ -10,13 +10,11 @@ on:
     paths-ignore:
       - '**.md'
       - 'doc/**'
-      - '.github/**'
   pull_request:
     branches: [ master, dev ]
     paths-ignore:
       - '**.md'
       - 'doc/**'
-      - '.github/**'
 
 jobs:
   build:
@@ -26,18 +24,18 @@ jobs:
       matrix:
         framework: ["Arduino", "IDF"]
         no_gfx: ["", -DNO_GFX]
-        no_fast_functions: ["", -DNO_FAST_FUNCTIONS]
-        no_cie1931: ["", -DNO_CIE1931]
-        virtual_panel: ["", -DVIRTUAL_PANE]
+#       no_fast_functions: ["", -DNO_FAST_FUNCTIONS]
+#       no_cie1931: ["", -DNO_CIE1931]
+#       virtual_panel: ["", -DVIRTUAL_PANE]
         example:
           - "examples/PIO_TestPatterns"
-        exclude:
-          - no_fast_functions: ""
-            virtual_panel: -DVIRTUAL_PANE
+#        exclude:
+#          - no_fast_functions: ""
+#            virtual_panel: -DVIRTUAL_PANE
 
     steps:
     - name: Checkout
-      uses: actions/checkout@v3
+      uses: actions/checkout@v4
     - name: Cache pip and platformio
       uses: actions/cache@v3
       with:
@@ -50,7 +48,7 @@ jobs:
       with:
         python-version: '3.x'
     - name: Install Platformio
-      run: pip install --upgrade platformio
+      run: pip install --upgrade platformio==6.1.6
     - name: Run PlatformIO CI (Arduino)
       if: ${{ matrix.framework == 'Arduino'}}
       env: 

CMakeLists.txt

@@ -5,17 +5,34 @@
 cmake_minimum_required(VERSION 3.5)
 idf_build_get_property(target IDF_TARGET)
 
-if(ARDUINO_ARCH_ESP32)
-    list(APPEND arduino_build arduino Adafruit-GFX-Library)
+if(ARDUINO_ARCH_ESP32 OR CONFIG_ESP32_HUB75_USE_GFX)
+    list(APPEND build_dependencies arduino Adafruit-GFX-Library)
 else()
-    list(APPEND esp_idf_build esp_lcd driver)
+    list(APPEND build_dependencies esp_lcd driver)
 endif()
-idf_component_register(SRCS "src/platforms/esp32/esp32_i2s_parallel_dma.cpp" "src/ESP32-HUB75-MatrixPanel-I2S-DMA.cpp" "src/ESP32-HUB75-MatrixPanel-leddrivers.cpp"
-                       src/platforms/${target}/gdma_lcd_parallel16.cpp
+
+if(${target} STREQUAL "esp32s3")
+  list(APPEND extra_srcs src/platforms/${target}/gdma_lcd_parallel16.cpp)
+endif()
+
+idf_component_register(SRCS "src/platforms/esp32/esp32_i2s_parallel_dma.cpp" "src/ESP32-HUB75-MatrixPanel-I2S-DMA.cpp" "src/ESP32-HUB75-MatrixPanel-leddrivers.cpp" ${extra_srcs}
                        INCLUDE_DIRS "./src"
-                       REQUIRES ${arduino_build} ${esp_idf_build}
                        )
 
+# Dependencies cannot be added to the REQUIRES argument of `idf_component_register` because (according to the build process
+# listed at https://docs.espressif.com/projects/esp-idf/en/v4.2/esp32/api-guides/build-system.html#build-process)
+# `idf_component_register` is processed during the "Enumeration" stage which happens before the sdkconfig file is loaded
+# in the "Processing" stage. So if dependencies are going to be loaded based on certain CONFIG_* variables we must
+# use `target_link_libraries` instead. This is the method used by Arduino's CMakeLists.txt file.
+idf_build_get_property(components BUILD_COMPONENTS)
+foreach(component_name IN LISTS build_dependencies)
+  if (NOT ${component_name} IN_LIST components)
+    message(FATAL_ERROR "Missing component: ${component_name}")
+  endif()
+  idf_component_get_property(lib_name ${component_name} COMPONENT_LIB)
+  target_link_libraries(${COMPONENT_LIB} PUBLIC ${lib_name})
+endforeach()
+
 # In case you are running into issues with "missing" header files from 3rd party libraries
 # you can add them to the REQUIRES section above. If you use some of the build options below
 # you probably want to remove (NO_GFX) or replace Adafruit-GFX-Library (USE_GFX_ROOT)
@@ -25,11 +42,14 @@ idf_component_register(SRCS "src/platforms/esp32/esp32_i2s_parallel_dma.cpp" "sr
 # target_compile_options(${COMPONENT_TARGET} PUBLIC -DNO_GFX)
 
 # esp-idf does not have any GFX library support yet, so we need to define NO_GFX
-if(ARDUINO_ARCH_ESP32)
+if(ARDUINO_ARCH_ESP32 OR CONFIG_ESP32_HUB75_USE_GFX)
 else()
     target_compile_options(${COMPONENT_TARGET} PUBLIC -DNO_GFX)
     if(${target} STREQUAL "esp32s3")
-        target_compile_options(${COMPONENT_TARGET} PUBLIC -DSPIRAM_FRAMEBUFFER)
+		# Don't enable PSRAM based framebuffer just because it's an S3.
+		# This is an advanced option and should only be used with an S3 with Octal-SPI RAM.
+        # target_compile_options(${COMPONENT_TARGET} PUBLIC -DSPIRAM_FRAMEBUFFER)
+		target_compile_options(${COMPONENT_TARGET} PUBLIC)
     endif()
 endif()
 

Kconfig.projbuild

@@ -0,0 +1,9 @@
+menu "ESP32 HUB75 Configuration"
+
+  config ESP32_HUB75_USE_GFX
+      bool "Use Adafruit GFX library."
+      default y
+      help
+          This option enables use of the Adafruit GFX library using the `Adafruit-GFX-Library` component.
+
+endmenu

README.md

@@ -54,7 +54,7 @@ A typical 64x32px panel at 24bpp colour uses about 20kB of internal memory.
 
 Please use the ['Memory Calculator'](/doc/memcalc.md) to see what is *typically* achievable with the typical ESP32. ![Memory Calculator](doc/memcalc.jpg)
 
-For the ESP32-S3 only, you can use SPIRAM/PSRAM to drive the HUB75 DMA buffer when using **Octal SPI-RAM** (i.e. ESP32 S3 N8R8 variant). However, due to bandwidth limitations, the maximum output frequency is limited to approx. 13Mhz, which will limit the real-world number of panels that can be chained without flicker. 
+For the ESP32-S3 only, you can use SPIRAM/PSRAM to drive the HUB75 DMA buffer when using an ESP32-S3 with **OCTAL SPI-RAM (PSTRAM)** (i.e. ESP32 S3 N8R8 variant). However, due to bandwidth limitations, the maximum output frequency is limited to approx. 13Mhz, which will limit the real-world number of panels that can be chained without flicker. Please do not use PSRAM as the DMA buffer if using QUAD SPI (Q-SPI), as it's too slow.
 
 To enable PSRAM support on the ESP32-S3, refer to [the build options](/doc/BuildOptions.md) to enable.
 
@@ -83,8 +83,10 @@ Due to the high-speed optimized nature of this library, only specific panels are
 * [RUC7258](http://www.ruichips.com/en/products.html?cateid=17496)
 * FM6126A AKA ICN2038S, [FM6124](https://datasheet4u.com/datasheet-pdf/FINEMADELECTRONICS/FM6124/pdf.php?id=1309677) (Refer to [PatternPlasma](/examples/2_PatternPlasma) example on how to use.)
 * SM5266P
+* DP3246 with SM5368 row addressing registers
 
-## Unsupported Panels
+## Unsupported chips
+* [SM1620B](https://github.com/mrfaptastic/ESP32-HUB75-MatrixPanel-DMA/issues/416)
 * RUL5358 / SHIFTREG_ABC_BIN_DE based panels are not supported.
 * ICN2053 / FM6353 based panels - Refer to [this library](https://github.com/LAutour/ESP32-HUB75-MatrixPanel-DMA-ICN2053), which is a fork of this library ( [discussion link](https://github.com/mrfaptastic/ESP32-HUB75-MatrixPanel-DMA/discussions/324)).
 * Any other panel not listed above.
@@ -94,7 +96,7 @@ Please use an [alternative library](https://github.com/2dom/PxMatrix) if you bou
 # Getting Started
 ## 1. Library Installation
 
-* Dependancy: You will need to install Adafruit_GFX from the "Library > Manage Libraries" menu.
+* Dependency: You will need to install Adafruit_GFX from the "Library > Manage Libraries" menu.
 * Install this library from the Arduino Library manager.
 
 Library also tested to work fine with PlatformIO, install into your PlatformIO projects' lib/ folder as appropriate. Or just add it into [platformio.ini](/doc/BuildOptions.md) [lib_deps](https://docs.platformio.org/en/latest/projectconf/section_env_library.html#lib-deps) section.
@@ -132,6 +134,8 @@ HUB75_I2S_CFG mxconfig(
 dma_display = new MatrixPanel_I2S_DMA(mxconfig);
 ```
 
+Make sure you also connect one of the HUB75 interfaces ground pins to a ground pin of the ESP32, otherwise you may get electrical artefacts on LED Matrix Panel.
+
 Various people have created PCBs for which one can simply connect an ESP32 to a PCB, and then the PCB to the HUB75 connector, such as:
 
 * Brian Lough's [ESP32 I2S Matrix Shield](http://blough.ie/i2smat/)
@@ -226,4 +230,6 @@ There are a number of great looking LED graphical display projects which leverag
 * [PaintYourDragon](https://github.com/PaintYourDragon) for the DMA logic for the ESP32-S3.
 * And lots of others, let me know if I've missed you.
 
+If you want to donate money to the project, please refer to [this discussion](https://github.com/mrfaptastic/ESP32-HUB75-MatrixPanel-DMA/discussions/349) about it. If you want to donate/buy an LED panel for the library author to improve compatibility and/or testing - please feel free to post in the same [discussion](https://github.com/mrfaptastic/ESP32-HUB75-MatrixPanel-DMA/discussions/349).
+
 ![It's better in real life](image.jpg)

examples/3_DoubleBuffer/3_DoubleBuffer.ino

@@ -1,3 +1,9 @@
+// Example uses the following configuration:  mxconfig.double_buff = true;
+// to enable double buffering, which means display->flipDMABuffer(); is required.
+
+// Bounce squares around the screen, doing the re-drawing in the background back-buffer.
+// Double buffering is not always required in reality.
+
 #include <ESP32-HUB75-MatrixPanel-I2S-DMA.h>
 
 MatrixPanel_I2S_DMA *display = nullptr;
@@ -32,14 +38,14 @@ void setup()
 
   Serial.println("...Starting Display");
   HUB75_I2S_CFG mxconfig;
-  //mxconfig.double_buff = true; // Turn of double buffer
-  mxconfig.clkphase = false;
+  mxconfig.double_buff = true; // <------------- Turn on double buffer
+  //mxconfig.clkphase = false;
 
   // OK, now we can create our matrix object
   display = new MatrixPanel_I2S_DMA(mxconfig);
   display->begin();  // setup display with pins as pre-defined in the library
 
-  // Create some Squares
+  // Create some random squares
   for (int i = 0; i < numSquares; i++)
   {
     Squares[i].square_size = random(2,10);
@@ -47,8 +53,6 @@ void setup()
     Squares[i].ypos = random(0, display->height() - Squares[i].square_size);
     Squares[i].velocityx = static_cast <float> (rand()) / static_cast <float> (RAND_MAX);
     Squares[i].velocityy = static_cast <float> (rand()) / static_cast <float> (RAND_MAX);
-    //Squares[i].xdir = (random(2) == 1) ? true:false;
-    //Squares[i].ydir = (random(2) == 1) ? true:false;
 
     int random_num = random(6);
     Squares[i].colour = colours[random_num];
@@ -57,9 +61,11 @@ void setup()
 
 void loop()
 {
-  display->flipDMABuffer(); // not used if double buffering isn't enabled
-  delay(25);
-  display->clearScreen();
+  
+  display->flipDMABuffer(); // Show the back buffer, set currently output buffer to the back (i.e. no longer being sent to LED panels)
+  display->clearScreen();   // Now clear the back-buffer
+
+  delay(16);  // <----------- Shouldn't see this clearscreen occur as it happens on the back buffer when double buffering is enabled.
 
   for (int i = 0; i < numSquares; i++)
   {

examples/3_FM6126Panel/README.md

@@ -1,3 +0,0 @@
-## FM6126 based LED Matrix Panel Reset ##
-
-FM6216 panels require a special reset sequence before they can be used, check your panel chipset if you have issues. Refer to this example.

examples/4_OtherShiftDriverPanel/4_OtherShiftDriverPanel.ino

@@ -1,19 +1,30 @@
-// How to use this library with a FM6126 panel, thanks goes to:
-// https://github.com/hzeller/rpi-rgb-led-matrix/issues/746
+/**********************************************************************
+ * The library by default supports simple 'shift register' based panels
+ * with A,B,C,D,E lines to select a specific row, but there are plenty
+ * of examples of new chips coming on the market that work different.
+ *
+ * Please search through the project's issues. For some of these chips
+ * (you will need to look at the back of your panel to identify), this
+ * library has workarounds. This can be configured through using one of:
+ 
+ 	// mxconfig.driver = HUB75_I2S_CFG::FM6126A;     
+	//mxconfig.driver = HUB75_I2S_CFG::ICN2038S;
+	//mxconfig.driver = HUB75_I2S_CFG::FM6124;
+	//mxconfig.driver = HUB75_I2S_CFG::MBI5124;	
+ */
+
 
 #include <Arduino.h>
 #include <ESP32-HUB75-MatrixPanel-I2S-DMA.h>
 #include <FastLED.h>
 
 ////////////////////////////////////////////////////////////////////
-// FM6126 support is still experimental
 
 // Output resolution and panel chain length configuration
 #define PANEL_RES_X 64 	   // Number of pixels wide of each INDIVIDUAL panel module. 
 #define PANEL_RES_Y 32 	   // Number of pixels tall of each INDIVIDUAL panel module.
 #define PANEL_CHAIN 1      // Total number of panels chained one to another
 
-
 // placeholder for the matrix object
 MatrixPanel_I2S_DMA *dma_display = nullptr;
 
@@ -34,21 +45,18 @@ CRGB ColorFromCurrentPalette(uint8_t index = 0, uint8_t brightness = 255, TBlend
 
 void setup(){
 
-	/*
-		The configuration for MatrixPanel_I2S_DMA object is held in HUB75_I2S_CFG structure,
-		All options has it's predefined default values. So we can create a new structure and redefine only the options we need
-
-		Please refer to the '2_PatternPlasma.ino' example for detailed example of how to use the MatrixPanel_I2S_DMA configuration
-		if you need to change the pin mappings etc.
-	*/
-
 	HUB75_I2S_CFG mxconfig(
 				PANEL_RES_X,   // module width
 				PANEL_RES_Y,   // module height
 				PANEL_CHAIN    // Chain length
 	);
 
-	mxconfig.driver = HUB75_I2S_CFG::FM6126A;     // in case that we use panels based on FM6126A chip, we can set it here before creating MatrixPanel_I2S_DMA object
+	// in case that we use panels based on FM6126A chip, we can set it here before creating MatrixPanel_I2S_DMA object
+	mxconfig.driver = HUB75_I2S_CFG::FM6126A;     
+	//mxconfig.driver = HUB75_I2S_CFG::ICN2038S;
+	//mxconfig.driver = HUB75_I2S_CFG::FM6124;
+	//mxconfig.driver = HUB75_I2S_CFG::MBI5124;	
+
 
 	// OK, now we can create our matrix object
 	dma_display = new MatrixPanel_I2S_DMA(mxconfig);
@@ -100,3 +108,7 @@ void loop(){
       fps = 0;
     }
 }
+
+
+// FM6126 panel , thanks goes to:
+// https://github.com/hzeller/rpi-rgb-led-matrix/issues/746

examples/4_OtherShiftDriverPanel/README.md

@@ -0,0 +1,13 @@
+## Ohter driver based LED Matrix Panels ##
+
+Limited support for other panels exists, but requires this to be passed as a configuration option when using the library.
+
+These panels require a special reset sequence before they can be used, check your panel chipset if you have issues. Refer to the example.
+
+
+```
+ 	mxconfig.driver = HUB75_I2S_CFG::FM6126A;     
+	mxconfig.driver = HUB75_I2S_CFG::ICN2038S;
+	mxconfig.driver = HUB75_I2S_CFG::FM6124;
+	mxconfig.driver = HUB75_I2S_CFG::MBI5124;	
+```

examples/AnimatedGIFPanel/AnimatedGIFPanel.ino

@@ -1,7 +0,0 @@
-// Example sketch which shows how to display a 64x32 animated GIF image stored in FLASH memory
-// on a 64x32 LED matrix
-//
-// Credits: https://github.com/bitbank2/AnimatedGIF/tree/master/examples/ESP32_LEDMatrix_I2S
-// 
-
-// Refer to: https://github.com/bitbank2/AnimatedGIF/blob/master/examples/ESP32_LEDMatrix_I2S/ESP32_LEDMatrix_I2S.ino

examples/AnimatedGIFPanel_SD/AnimatedGIFPanel_SD.ino

@@ -0,0 +1,268 @@
+/*********************************************************************
+ * AnimatedGif LED Matrix Panel example where the GIFs are 
+ * stored on a SD card connected to the ESP32 using the
+ * standard GPIO pins used for SD card acces via. SPI.
+ *
+ * Put the gifs into a directory called 'gifs' (case sensitive) on
+ * a FAT32 formatted SDcard.
+ ********************************************************************/
+#include "FS.h"
+#include "SD.h"
+#include "SPI.h"
+#include <ESP32-HUB75-MatrixPanel-I2S-DMA.h> 
+#include <AnimatedGIF.h>
+
+/********************************************************************
+ * Pin mapping below is for LOLIN D32 (ESP 32)
+ *
+ * Default pin mapping used by this library is NOT compatable with the use of the 
+ * ESP32-Arduino 'SD' card library (there is overlap). As such, some of the pins 
+ * used for the HUB75 panel need to be shifted.
+ * 
+ * 'SD' card library requires GPIO 23, 18 and 19 
+ *  https://github.com/espressif/arduino-esp32/tree/master/libraries/SD
+ * 
+ */
+
+/*
+ * Connect the SD card to the following pins:
+ *
+ * SD Card | ESP32
+ *    D2       -
+ *    D3       SS
+ *    CMD      MOSI
+ *    VSS      GND
+ *    VDD      3.3V
+ *    CLK      SCK
+ *    VSS      GND
+ *    D0       MISO
+ *    D1       -
+ */
+
+/**** SD Card GPIO mappings ****/
+#define SS_PIN          5
+//#define MOSI_PIN        23
+//#define MISO_PIN        19
+//#define CLK_PIN         18
+
+
+/**** HUB75 GPIO mapping ****/
+// GPIO 34+ are on the ESP32 are input only!!
+// https://randomnerdtutorials.com/esp32-pinout-reference-gpios/
+
+#define A_PIN   33  // remap esp32 library default from 23 to 33
+#define B_PIN   32  // remap esp32 library default from 19 to 32
+#define C_PIN   22   // remap esp32 library defaultfrom 5 to 22
+
+//#define R1_PIN  25  // library default for the esp32, unchanged
+//#define G1_PIN  26  // library default for the esp32, unchanged
+//#define B1_PIN  27  // library default for the esp32, unchanged
+//#define R2_PIN  14  // library default for the esp32, unchanged
+//#define G2_PIN  12  // library default for the esp32, unchanged
+//#define B2_PIN  13  // library default for the esp32, unchanged
+//#define D_PIN   17  // library default for the esp32, unchanged
+//#define E_PIN   -1 // IMPORTANT: Change to a valid pin if using a 64x64px panel.
+            
+//#define LAT_PIN 4  // library default for the esp32, unchanged
+//#define OE_PIN  15  // library default for the esp32, unchanged
+//#define CLK_PIN 16  // library default for the esp32, unchanged
+
+/***************************************************************
+ * HUB 75 LED DMA Matrix Panel Configuration
+ **************************************************************/
+#define PANEL_RES_X 64      // Number of pixels wide of each INDIVIDUAL panel module. 
+#define PANEL_RES_Y 32     // Number of pixels tall of each INDIVIDUAL panel module.
+#define PANEL_CHAIN 1      // Total number of panels chained one to another
+
+/**************************************************************/
+
+AnimatedGIF gif;
+MatrixPanel_I2S_DMA *dma_display = nullptr;
+
+static int totalFiles = 0; // GIF files count
+
+static File FSGifFile; // temp gif file holder
+static File GifRootFolder; // directory listing
+
+std::vector<std::string> GifFiles; // GIF files path
+
+const int maxGifDuration    = 30000; // ms, max GIF duration
+
+#include "gif_functions.hpp"
+#include "sdcard_functions.hpp"
+ 
+
+/**************************************************************/
+void draw_test_patterns();
+int gifPlay( const char* gifPath )
+{ // 0=infinite
+
+  if( ! gif.open( gifPath, GIFOpenFile, GIFCloseFile, GIFReadFile, GIFSeekFile, GIFDraw ) ) {
+    log_n("Could not open gif %s", gifPath );
+  }
+
+  Serial.print("Playing: "); Serial.println(gifPath);
+
+  int frameDelay = 0; // store delay for the last frame
+  int then = 0; // store overall delay
+
+  while (gif.playFrame(true, &frameDelay)) {
+
+    then += frameDelay;
+    if( then > maxGifDuration ) { // avoid being trapped in infinite GIF's
+      //log_w("Broke the GIF loop, max duration exceeded");
+      break;
+    }
+  }
+
+  gif.close();
+
+  return then;
+}
+
+
+void setup()
+{
+    Serial.begin(115200);
+
+    // **************************** Setup SD Card access via SPI ****************************
+    if(!SD.begin(SS_PIN)){
+        //  bool begin(uint8_t ssPin=SS, SPIClass &spi=SPI, uint32_t frequency=4000000, const char * mountpoint="/sd", uint8_t max_files=5, bool format_if_empty=false);      
+        Serial.println("Card Mount Failed");
+        return;
+    }
+    uint8_t cardType = SD.cardType();
+
+    if(cardType == CARD_NONE){
+        Serial.println("No SD card attached");
+        return;
+    }
+
+    Serial.print("SD Card Type: ");
+    if(cardType == CARD_MMC){
+        Serial.println("MMC");
+    } else if(cardType == CARD_SD){
+        Serial.println("SDSC");
+    } else if(cardType == CARD_SDHC){
+        Serial.println("SDHC");
+    } else {
+        Serial.println("UNKNOWN");
+    }
+
+    uint64_t cardSize = SD.cardSize() / (1024 * 1024);
+    Serial.printf("SD Card Size: %lluMB\n", cardSize);
+
+    //listDir(SD, "/", 1, false);
+
+    Serial.printf("Total space: %lluMB\n", SD.totalBytes() / (1024 * 1024));
+    Serial.printf("Used space: %lluMB\n", SD.usedBytes() / (1024 * 1024));
+
+
+
+    // **************************** Setup DMA Matrix ****************************
+    HUB75_I2S_CFG mxconfig(
+      PANEL_RES_X,   // module width
+      PANEL_RES_Y,   // module height
+      PANEL_CHAIN    // Chain length
+    );
+
+    // Need to remap these HUB75 DMA pins because the SPI SDCard is using them.
+    // Otherwise the SD Card will not work.
+    mxconfig.gpio.a = A_PIN;
+    mxconfig.gpio.b = B_PIN;
+    mxconfig.gpio.c = C_PIN;
+ //   mxconfig.gpio.d = D_PIN;    
+
+    //mxconfig.clkphase = false;
+    //mxconfig.driver = HUB75_I2S_CFG::FM6126A;
+
+    // Display Setup
+    dma_display = new MatrixPanel_I2S_DMA(mxconfig);
+
+    // Allocate memory and start DMA display
+    if( not dma_display->begin() )
+        Serial.println("****** !KABOOM! HUB75 memory allocation failed ***********");
+ 
+    dma_display->setBrightness8(128); //0-255
+    dma_display->clearScreen();
+
+
+    // **************************** Setup Sketch ****************************
+    Serial.println("Starting AnimatedGIFs Sketch");
+
+    // SD CARD STOPS WORKING WITH DMA DISPLAY ENABLED>...
+
+    File root = SD.open("/gifs");
+    if(!root){
+        Serial.println("Failed to open directory");
+        return;
+    }
+
+    File file = root.openNextFile();
+    while(file){
+        if(!file.isDirectory())
+        {
+            Serial.print("  FILE: ");
+            Serial.print(file.name());
+            Serial.print("  SIZE: ");
+            Serial.println(file.size());
+
+            std::string filename = "/gifs/" + std::string(file.name());
+            Serial.println(filename.c_str());
+            
+            GifFiles.push_back( filename );
+         //   Serial.println("Adding to gif list:" + String(filename));
+            totalFiles++;
+    
+        }
+        file = root.openNextFile();
+    }
+
+    file.close();
+    Serial.printf("Found %d GIFs to play.", totalFiles);
+    //totalFiles = getGifInventory("/gifs");
+
+
+
+  // This is important - Set the right endianness.
+  gif.begin(LITTLE_ENDIAN_PIXELS);
+
+}
+
+void loop(){
+
+      // Iterate over a vector using range based for loop
+    for(auto & elem : GifFiles)
+    {
+        gifPlay( elem.c_str() );
+        gif.reset();
+        delay(500);
+    }
+
+}
+
+void draw_test_patterns()
+{
+ // fix the screen with green
+  dma_display->fillRect(0, 0, dma_display->width(), dma_display->height(), dma_display->color444(0, 15, 0));
+  delay(500);
+
+  // draw a box in yellow
+  dma_display->drawRect(0, 0, dma_display->width(), dma_display->height(), dma_display->color444(15, 15, 0));
+  delay(500);
+
+  // draw an 'X' in red
+  dma_display->drawLine(0, 0, dma_display->width()-1, dma_display->height()-1, dma_display->color444(15, 0, 0));
+  dma_display->drawLine(dma_display->width()-1, 0, 0, dma_display->height()-1, dma_display->color444(15, 0, 0));
+  delay(500);
+
+  // draw a blue circle
+  dma_display->drawCircle(10, 10, 10, dma_display->color444(0, 0, 15));
+  delay(500);
+
+  // fill a violet circle
+  dma_display->fillCircle(40, 21, 10, dma_display->color444(15, 0, 15));
+  delay(500);
+  delay(1000);
+
+}

examples/AnimatedGIFPanel_SD/Readme.md

@@ -0,0 +1,15 @@
+# ESP32-HUB75-MatrixPanel-DMA SDCard example
+
+A very basic example using the 'Animated GIF' library by Larry Bank + the SD / File system library provided for Arduino by Espressif.
+
+Some default HUB75 pins need to be remapped to accomodate for the SD Card.
+
+![image](esp32_sdcard.jpg)
+
+## How to use it?
+
+1. Format a SD Card with FAT32 file system (default setting)
+2. Create a directory called 'gifs'
+3. Drop your gifs in there. The resolution of the GIFS must match that of the display.
+
+

examples/AnimatedGIFPanel_SD/gif_functions.hpp

@@ -0,0 +1,132 @@
+
+// Code copied from AnimatedGIF examples
+
+#ifndef M5STACK_SD
+ // for custom ESP32 builds
+ #define M5STACK_SD SD
+#endif
+
+
+static void * GIFOpenFile(const char *fname, int32_t *pSize)
+{
+  //log_d("GIFOpenFile( %s )\n", fname );
+  FSGifFile = M5STACK_SD.open(fname);
+  if (FSGifFile) {
+    *pSize = FSGifFile.size();
+    return (void *)&FSGifFile;
+  }
+  return NULL;
+}
+
+
+static void GIFCloseFile(void *pHandle)
+{
+  File *f = static_cast<File *>(pHandle);
+  if (f != NULL)
+     f->close();
+}
+
+
+static int32_t GIFReadFile(GIFFILE *pFile, uint8_t *pBuf, int32_t iLen)
+{
+  int32_t iBytesRead;
+  iBytesRead = iLen;
+  File *f = static_cast<File *>(pFile->fHandle);
+  // Note: If you read a file all the way to the last byte, seek() stops working
+  if ((pFile->iSize - pFile->iPos) < iLen)
+      iBytesRead = pFile->iSize - pFile->iPos - 1; // <-- ugly work-around
+  if (iBytesRead <= 0)
+      return 0;
+  iBytesRead = (int32_t)f->read(pBuf, iBytesRead);
+  pFile->iPos = f->position();
+  return iBytesRead;
+}
+
+
+static int32_t GIFSeekFile(GIFFILE *pFile, int32_t iPosition)
+{
+  int i = micros();
+  File *f = static_cast<File *>(pFile->fHandle);
+  f->seek(iPosition);
+  pFile->iPos = (int32_t)f->position();
+  i = micros() - i;
+  //log_d("Seek time = %d us\n", i);
+  return pFile->iPos;
+}
+
+
+// Draw a line of image directly on the LCD
+void GIFDraw(GIFDRAW *pDraw)
+{
+  uint8_t *s;
+  uint16_t *d, *usPalette, usTemp[320];
+  int x, y, iWidth;
+
+  iWidth = pDraw->iWidth;
+  if (iWidth > PANEL_RES_X)
+      iWidth = PANEL_RES_X;
+  usPalette = pDraw->pPalette;
+  y = pDraw->iY + pDraw->y; // current line
+
+  s = pDraw->pPixels;
+  if (pDraw->ucDisposalMethod == 2) {// restore to background color
+    for (x=0; x<iWidth; x++) {
+      if (s[x] == pDraw->ucTransparent)
+          s[x] = pDraw->ucBackground;
+    }
+    pDraw->ucHasTransparency = 0;
+  }
+  // Apply the new pixels to the main image
+  if (pDraw->ucHasTransparency) { // if transparency used
+    uint8_t *pEnd, c, ucTransparent = pDraw->ucTransparent;
+    int x, iCount;
+    pEnd = s + iWidth;
+    x = 0;
+    iCount = 0; // count non-transparent pixels
+    while(x < iWidth) {
+      c = ucTransparent-1;
+      d = usTemp;
+      while (c != ucTransparent && s < pEnd) {
+        c = *s++;
+        if (c == ucTransparent) { // done, stop
+          s--; // back up to treat it like transparent
+        } else { // opaque
+            *d++ = usPalette[c];
+            iCount++;
+        }
+      } // while looking for opaque pixels
+      if (iCount) { // any opaque pixels?
+          for(int xOffset = 0; xOffset < iCount; xOffset++ ){
+            dma_display->drawPixel(x + xOffset, y, usTemp[xOffset]); // 565 Color Format
+          }
+        x += iCount;
+        iCount = 0;
+      }
+      // no, look for a run of transparent pixels
+      c = ucTransparent;
+      while (c == ucTransparent && s < pEnd) {
+        c = *s++;
+        if (c == ucTransparent)
+            iCount++;
+        else
+            s--;
+      }
+      if (iCount) {
+        x += iCount; // skip these
+        iCount = 0;
+      }
+    }
+  } else {
+    s = pDraw->pPixels;
+    // Translate the 8-bit pixels through the RGB565 palette (already byte reversed)
+    for (x=0; x<iWidth; x++)
+      dma_display->drawPixel(x, y, usPalette[*s++]); // color 565
+      /*
+      usTemp[x] = usPalette[*s++];
+
+      for (x=0; x<pDraw->iWidth; x++) {
+        dma_display->drawPixel(x, y, usTemp[*s++]); // color 565
+      } */     
+
+  }
+} /* GIFDraw() */

examples/AnimatedGIFPanel_SD/sdcard_functions.hpp

@@ -0,0 +1,102 @@
+/************************ SD Card Code ************************/
+// As per: https://github.com/espressif/arduino-esp32/tree/master/libraries/SD/examples/SD_Test
+
+
+
+void listDir(fs::FS &fs, const char * dirname, uint8_t levels, bool add_to_gif_list = false){
+    Serial.printf("Listing directory: %s\n", dirname);
+
+    File root = fs.open(dirname);
+    if(!root){
+        Serial.println("Failed to open directory");
+        return;
+    }
+    if(!root.isDirectory()){
+        Serial.println("Not a directory");
+        return;
+    }
+
+    File file = root.openNextFile();
+    while(file){
+        if(file.isDirectory()){
+            Serial.print("  DIR : ");
+            Serial.println(file.name());
+            if(levels){
+                listDir(fs, file.path(), levels -1, false);
+            }
+        } else {
+            Serial.print("  FILE: ");
+            Serial.print(file.name());
+            Serial.print("  SIZE: ");
+            Serial.println(file.size());
+
+            if (add_to_gif_list && levels == 0) 
+            {
+              GifFiles.push_back( std::string(dirname) +  file.name() );
+              Serial.println("Adding to gif list:" + String(dirname) +"/" + file.name());
+              totalFiles++;
+            }
+        }
+        file = root.openNextFile();
+    }
+
+    file.close();
+}
+
+void readFile(fs::FS &fs, const char * path){
+    Serial.printf("Reading file: %s\n", path);
+
+    File file = fs.open(path);
+    if(!file){
+        Serial.println("Failed to open file for reading");
+        return;
+    }
+
+    Serial.print("Read from file: ");
+    while(file.available()){
+        Serial.write(file.read());
+    }
+    file.close();
+}
+
+void testFileIO(fs::FS &fs, const char * path){
+    File file = fs.open(path);
+    static uint8_t buf[512];
+    size_t len = 0;
+    uint32_t start = millis();
+    uint32_t end = start;
+    if(file){
+        len = file.size();
+        size_t flen = len;
+        start = millis();
+        while(len){
+            size_t toRead = len;
+            if(toRead > 512){
+                toRead = 512;
+            }
+            file.read(buf, toRead);
+            len -= toRead;
+        }
+        end = millis() - start;
+        Serial.printf("%u bytes read for %u ms\n", flen, end);
+        file.close();
+    } else {
+        Serial.println("Failed to open file for reading");
+    }
+
+
+    file = fs.open(path, FILE_WRITE);
+    if(!file){
+        Serial.println("Failed to open file for writing");
+        return;
+    }
+
+    size_t i;
+    start = millis();
+    for(i=0; i<2048; i++){
+        file.write(buf, 512);
+    }
+    end = millis() - start;
+    Serial.printf("%u bytes written for %u ms\n", 2048 * 512, end);
+    file.close();
+}

examples/AnimatedGIFPanel_SPIFFS/AnimatedGIFPanel_SPIFFS.ino

@@ -0,0 +1,290 @@
+// Example sketch which shows how to display a 64x32 animated GIF image stored in FLASH memory
+// on a 64x32 LED matrix
+//
+// Credits: https://github.com/bitbank2/AnimatedGIF/tree/master/examples/ESP32_LEDMatrix_I2S
+// 
+
+/* INSTRUCTIONS
+ *
+ * 1. First Run the 'ESP32 Sketch Data Upload Tool' in Arduino from the 'Tools' Menu.
+ *    - If you don't know what this is or see it as an option, then read this:
+ *      https://github.com/me-no-dev/arduino-esp32fs-plugin 
+ *    - This tool will upload the contents of the data/ directory in the sketch folder onto
+ *      the ESP32 itself.
+ *
+ * 2. You can drop any animated GIF you want in there, but keep it to the resolution of the 
+ *    MATRIX you're displaying to. To resize a gif, use this online website: https://ezgif.com/
+ *
+ * 3. Have fun.
+ */
+
+#define FILESYSTEM SPIFFS
+#include <SPIFFS.h>
+#include <AnimatedGIF.h>
+#include <ESP32-HUB75-MatrixPanel-I2S-DMA.h>
+
+// ----------------------------
+
+/* 
+ * Below is an is the 'legacy' way of initialising the MatrixPanel_I2S_DMA class.
+ * i.e. MATRIX_WIDTH and MATRIX_HEIGHT are modified by compile-time directives.
+ * By default the library assumes a single 64x32 pixel panel is connected.
+ *
+ * Refer to the example '2_PatternPlasma' on the new / correct way to setup this library
+ * for different resolutions / panel chain lengths within the sketch 'setup()'.
+ * 
+ */
+
+#define PANEL_RES_X 64      // Number of pixels wide of each INDIVIDUAL panel module. 
+#define PANEL_RES_Y 32     // Number of pixels tall of each INDIVIDUAL panel module.
+#define PANEL_CHAIN 1      // Total number of panels chained one to another
+ 
+//MatrixPanel_I2S_DMA dma_display;
+MatrixPanel_I2S_DMA *dma_display = nullptr;
+
+uint16_t myBLACK = dma_display->color565(0, 0, 0);
+uint16_t myWHITE = dma_display->color565(255, 255, 255);
+uint16_t myRED = dma_display->color565(255, 0, 0);
+uint16_t myGREEN = dma_display->color565(0, 255, 0);
+uint16_t myBLUE = dma_display->color565(0, 0, 255);
+
+
+AnimatedGIF gif;
+File f;
+int x_offset, y_offset;
+
+
+
+// Draw a line of image directly on the LED Matrix
+void GIFDraw(GIFDRAW *pDraw)
+{
+    uint8_t *s;
+    uint16_t *d, *usPalette, usTemp[320];
+    int x, y, iWidth;
+
+  iWidth = pDraw->iWidth;
+  if (iWidth > MATRIX_WIDTH)
+      iWidth = MATRIX_WIDTH;
+
+    usPalette = pDraw->pPalette;
+    y = pDraw->iY + pDraw->y; // current line
+    
+    s = pDraw->pPixels;
+    if (pDraw->ucDisposalMethod == 2) // restore to background color
+    {
+      for (x=0; x<iWidth; x++)
+      {
+        if (s[x] == pDraw->ucTransparent)
+           s[x] = pDraw->ucBackground;
+      }
+      pDraw->ucHasTransparency = 0;
+    }
+    // Apply the new pixels to the main image
+    if (pDraw->ucHasTransparency) // if transparency used
+    {
+      uint8_t *pEnd, c, ucTransparent = pDraw->ucTransparent;
+      int x, iCount;
+      pEnd = s + pDraw->iWidth;
+      x = 0;
+      iCount = 0; // count non-transparent pixels
+      while(x < pDraw->iWidth)
+      {
+        c = ucTransparent-1;
+        d = usTemp;
+        while (c != ucTransparent && s < pEnd)
+        {
+          c = *s++;
+          if (c == ucTransparent) // done, stop
+          {
+            s--; // back up to treat it like transparent
+          }
+          else // opaque
+          {
+             *d++ = usPalette[c];
+             iCount++;
+          }
+        } // while looking for opaque pixels
+        if (iCount) // any opaque pixels?
+        {
+          for(int xOffset = 0; xOffset < iCount; xOffset++ ){
+            dma_display->drawPixel(x + xOffset, y, usTemp[xOffset]); // 565 Color Format
+          }
+          x += iCount;
+          iCount = 0;
+        }
+        // no, look for a run of transparent pixels
+        c = ucTransparent;
+        while (c == ucTransparent && s < pEnd)
+        {
+          c = *s++;
+          if (c == ucTransparent)
+             iCount++;
+          else
+             s--; 
+        }
+        if (iCount)
+        {
+          x += iCount; // skip these
+          iCount = 0;
+        }
+      }
+    }
+    else // does not have transparency
+    {
+      s = pDraw->pPixels;
+      // Translate the 8-bit pixels through the RGB565 palette (already byte reversed)
+      for (x=0; x<pDraw->iWidth; x++)
+      {
+        dma_display->drawPixel(x, y, usPalette[*s++]); // color 565
+      }
+    }
+} /* GIFDraw() */
+
+
+void * GIFOpenFile(const char *fname, int32_t *pSize)
+{
+  Serial.print("Playing gif: ");
+  Serial.println(fname);
+  f = FILESYSTEM.open(fname);
+  if (f)
+  {
+    *pSize = f.size();
+    return (void *)&f;
+  }
+  return NULL;
+} /* GIFOpenFile() */
+
+void GIFCloseFile(void *pHandle)
+{
+  File *f = static_cast<File *>(pHandle);
+  if (f != NULL)
+     f->close();
+} /* GIFCloseFile() */
+
+int32_t GIFReadFile(GIFFILE *pFile, uint8_t *pBuf, int32_t iLen)
+{
+    int32_t iBytesRead;
+    iBytesRead = iLen;
+    File *f = static_cast<File *>(pFile->fHandle);
+    // Note: If you read a file all the way to the last byte, seek() stops working
+    if ((pFile->iSize - pFile->iPos) < iLen)
+       iBytesRead = pFile->iSize - pFile->iPos - 1; // <-- ugly work-around
+    if (iBytesRead <= 0)
+       return 0;
+    iBytesRead = (int32_t)f->read(pBuf, iBytesRead);
+    pFile->iPos = f->position();
+    return iBytesRead;
+} /* GIFReadFile() */
+
+int32_t GIFSeekFile(GIFFILE *pFile, int32_t iPosition)
+{ 
+  int i = micros();
+  File *f = static_cast<File *>(pFile->fHandle);
+  f->seek(iPosition);
+  pFile->iPos = (int32_t)f->position();
+  i = micros() - i;
+//  Serial.printf("Seek time = %d us\n", i);
+  return pFile->iPos;
+} /* GIFSeekFile() */
+
+unsigned long start_tick = 0;
+
+void ShowGIF(char *name)
+{
+  start_tick = millis();
+   
+  if (gif.open(name, GIFOpenFile, GIFCloseFile, GIFReadFile, GIFSeekFile, GIFDraw))
+  {
+    x_offset = (MATRIX_WIDTH - gif.getCanvasWidth())/2;
+    if (x_offset < 0) x_offset = 0;
+    y_offset = (MATRIX_HEIGHT - gif.getCanvasHeight())/2;
+    if (y_offset < 0) y_offset = 0;
+    Serial.printf("Successfully opened GIF; Canvas size = %d x %d\n", gif.getCanvasWidth(), gif.getCanvasHeight());
+    Serial.flush();
+    while (gif.playFrame(true, NULL))
+    {      
+      if ( (millis() - start_tick) > 8000) { // we'll get bored after about 8 seconds of the same looping gif
+        break;
+      }
+    }
+    gif.close();
+  }
+
+} /* ShowGIF() */
+
+
+
+/************************* Arduino Sketch Setup and Loop() *******************************/
+void setup() {
+  Serial.begin(115200);
+  delay(1000);
+
+  HUB75_I2S_CFG mxconfig(
+    PANEL_RES_X,   // module width
+    PANEL_RES_Y,   // module height
+    PANEL_CHAIN    // Chain length
+  );
+
+ // mxconfig.gpio.e = 18;
+ // mxconfig.clkphase = false;
+  //mxconfig.driver = HUB75_I2S_CFG::FM6126A;
+
+  // Display Setup
+  dma_display = new MatrixPanel_I2S_DMA(mxconfig);
+  dma_display->begin();
+  dma_display->setBrightness8(128); //0-255
+  dma_display->clearScreen();
+  dma_display->fillScreen(myWHITE);
+
+  Serial.println("Starting AnimatedGIFs Sketch");
+
+  // Start filesystem
+  Serial.println(" * Loading SPIFFS");
+  if(!SPIFFS.begin()){
+        Serial.println("SPIFFS Mount Failed");
+  }
+  
+  dma_display->begin();
+  
+  /* all other pixel drawing functions can only be called after .begin() */
+  dma_display->fillScreen(dma_display->color565(0, 0, 0));
+  gif.begin(LITTLE_ENDIAN_PIXELS);
+
+}
+
+String gifDir = "/gifs"; // play all GIFs in this directory on the SD card
+char filePath[256] = { 0 };
+File root, gifFile;
+
+void loop() 
+{
+   while (1) // run forever
+   {
+      
+      root = FILESYSTEM.open(gifDir);
+      if (root)
+      {
+           gifFile = root.openNextFile();
+            while (gifFile)
+            {
+              if (!gifFile.isDirectory()) // play it
+              {
+                
+                // C-strings... urghh...                
+                memset(filePath, 0x0, sizeof(filePath));                
+                strcpy(filePath, gifFile.path());
+                
+                // Show it.
+                ShowGIF(filePath);
+               
+              }
+              gifFile.close();
+              gifFile = root.openNextFile();
+            }
+         root.close();
+      } // root
+      
+      delay(1000); // pause before restarting
+      
+   } // while
+}

examples/ChainedPanels/ChainedPanels.ino

@@ -1,139 +1,29 @@
 /******************************************************************************
-    -----------
-    Steps to use
-    -----------
+    -------------------------------------------------------------------------
+    Steps to create a virtual display made up of a chain of panels in a grid
+    -------------------------------------------------------------------------
 
-    1) In the sketch (i.e. this example):
+    Read the documentation!
+    https://github.com/mrfaptastic/ESP32-HUB75-MatrixPanel-DMA/tree/master/examples/ChainedPanels
+
+    tl/dr:
+    
+    - Set values for NUM_ROWS, NUM_COLS, PANEL_RES_X, PANEL_RES_Y, PANEL_CHAIN_TYPE. 
 
-    - Set values for NUM_ROWS, NUM_COLS, PANEL_RES_X, PANEL_RES_Y, PANEL_CHAIN. 
-      There are comments beside them explaining what they are in more detail.
     - Other than where the matrix is defined and matrix.begin in the setup, you 
       should now be using the virtual display for everything (drawing pixels, writing text etc).
        You can do a find and replace of all calls if it's an existing sketch
       (just make sure you don't replace the definition and the matrix.begin)
+
     - If the sketch makes use of MATRIX_HEIGHT or MATRIX_WIDTH, these will need to be 
       replaced with the width and height of your virtual screen. 
       Either make new defines and use that, or you can use virtualDisp.width() or .height()
 
-    Thanks to:
-
-    * Brian Lough for the original example as raised in this issue:
-      https://github.com/mrfaptastic/ESP32-HUB75-MatrixPanel-I2S-DMA/issues/26
-
-      YouTube: https://www.youtube.com/brianlough
-      Tindie: https://www.tindie.com/stores/brianlough/
-      Twitter: https://twitter.com/witnessmenow
-
-    * Galaxy-Man for the kind donation of panels make/test that this is possible:
-      https://github.com/Galaxy-Man
-
 *****************************************************************************/
+// 1) Include key virtual display library
+    #include <ESP32-VirtualMatrixPanel-I2S-DMA.h>
 
-
- /******************************************************************************
-  * VIRTUAL DISPLAY / MATRIX PANEL CHAINING CONFIGURATION
-  * 
-  * Note 1: If chaining from the top right to the left, and then S curving down
-  *         then serpentine_chain = true and top_down_chain = true
-  *         (these being the last two parameters of the virtualDisp(...) constructor.
-  * 
-  * Note 2: If chaining starts from the bottom up, then top_down_chain = false.
-  * 
-  * Note 3: By default, this library has serpentine_chain = true, that is, every 
-  *         second row has the panels 'upside down' (rotated 180), so the output
-  *         pin of the row above is right above the input connector of the next 
-  *         row.
-  
-  Example 1 panel chaining:
-  +-----------------+-----------------+-------------------+
-  | 64x32px PANEL 3 | 64x32px PANEL 2 | 64x32px PANEL 1   |
-  |        ------------   <--------   | ------------xx    |
-  | [OUT]  |   [IN] | [OUT]      [IN] | [OUT]    [ESP IN] |
-  +--------|--------+-----------------+-------------------+
-  | 64x32px|PANEL 4 | 64x32px PANEL 5 | 64x32px PANEL 6   |
-  |       \|/   ---------->           |  ----->           |
-  | [IN]      [OUT] | [IN]      [OUT] | [IN]      [OUT]   |
-  +-----------------+-----------------+-------------------+
-
-  Example 1 configuration:
-    
-    #define PANEL_RES_X 64 // Number of pixels wide of each INDIVIDUAL panel module. 
-    #define PANEL_RES_Y 32 // Number of pixels tall of each INDIVIDUAL panel module.
-
-    #define NUM_ROWS 2 // Number of rows of chained INDIVIDUAL PANELS
-    #define NUM_COLS 3 // Number of INDIVIDUAL PANELS per ROW
-
-    virtualDisp(dma_display, NUM_ROWS, NUM_COLS, PANEL_RES_X, PANEL_RES_Y, true, true);
-
-    = 192x64 px virtual display, with the top left of panel 3 being pixel co-ord (0,0)
-
-  ==========================================================
-
-  Example 2 panel chaining:
-
-  +-------------------+
-  | 64x32px PANEL 1   |
-  | ----------------- |
-  | [OUT]    [ESP IN] |
-  +-------------------+
-  | 64x32px PANEL 2   |
-  |                   |
-  | [IN]      [OUT]   |
-  +-------------------+
-  | 64x32px PANEL 3   |
-  |                   |
-  | [OUT]      [IN]   |
-  +-------------------+
-  | 64x32px PANEL 4   |
-  |                   |
-  | [IN]      [OUT]   |
-  +-------------------+    
-
-  Example 2 configuration:
-    
-    #define PANEL_RES_X 64 // Number of pixels wide of each INDIVIDUAL panel module. 
-    #define PANEL_RES_Y 32 // Number of pixels tall of each INDIVIDUAL panel module.
-
-    #define NUM_ROWS 4 // Number of rows of chained INDIVIDUAL PANELS
-    #define NUM_COLS 1 // Number of INDIVIDUAL PANELS per ROW
-
-    virtualDisp(dma_display, NUM_ROWS, NUM_COLS, PANEL_RES_X, PANEL_RES_Y, true, true);
-
-    virtualDisp(dma_display, NUM_ROWS, NUM_COLS, PANEL_RES_X, PANEL_RES_Y, true, true);     
-
-    = 128x64 px virtual display, with the top left of panel 1 being pixel co-ord (0,0)
-
-  ==========================================================
-
-  Example 3 panel chaining (bottom up):
-
-  +-----------------+-----------------+
-  | 64x32px PANEL 4 | 64x32px PANEL 3 | 
-  |             <----------           | 
-  | [OUT]      [IN] | [OUT]      [in] | 
-  +-----------------+-----------------+
-  | 64x32px PANEL 1 | 64x32px PANEL 2 | 
-  |             ---------->           | 
-  | [ESP IN]  [OUT] | [IN]      [OUT] | 
-  +-----------------+-----------------+
-
-  Example 1 configuration:
-    
-    #define PANEL_RES_X 64 // Number of pixels wide of each INDIVIDUAL panel module. 
-    #define PANEL_RES_Y 32 // Number of pixels tall of each INDIVIDUAL panel module.
-
-    #define NUM_ROWS 2 // Number of rows of chained INDIVIDUAL PANELS
-    #define NUM_COLS 2 // Number of INDIVIDUAL PANELS per ROW
-
-    virtualDisp(dma_display, NUM_ROWS, NUM_COLS, PANEL_RES_X, PANEL_RES_Y, true, false);
-
-    = 128x64 px virtual display, with the top left of panel 4 being pixel co-ord (0,0)  
-
-*/
-
-
-
-
+// 2) Set configuration
     #define PANEL_RES_X 64 // Number of pixels wide of each INDIVIDUAL panel module. 
     #define PANEL_RES_Y 32 // Number of pixels tall of each INDIVIDUAL panel module.
 
@@ -141,12 +31,31 @@
     #define NUM_COLS 2 // Number of INDIVIDUAL PANELS per ROW
     #define PANEL_CHAIN NUM_ROWS*NUM_COLS    // total number of panels chained one to another
 
-// Change this to your needs, for details on VirtualPanel pls read the PDF!
-#define SERPENT true
-#define TOPDOWN false
+    /* Configure the serpetine chaining approach. Options are:
+        CHAIN_TOP_LEFT_DOWN
+        CHAIN_TOP_RIGHT_DOWN
+        CHAIN_BOTTOM_LEFT_UP
+        CHAIN_BOTTOM_RIGHT_UP
 
-// library includes
-#include <ESP32-VirtualMatrixPanel-I2S-DMA.h>
+        The location (i.e. 'TOP_LEFT', 'BOTTOM_RIGHT') etc. refers to the starting point where 
+        the ESP32 is located, and how the chain of panels will 'roll out' from there.
+
+        In this example we're using 'CHAIN_BOTTOM_LEFT_UP' which would look like this in the real world:
+
+        Chain of 4 x 64x32 panels with the ESP at the BOTTOM_LEFT:
+
+        +---------+---------+
+        |    4    |    3    |
+        |         |         |
+        +---------+---------+
+        |    1    |    2    |
+        |  (ESP)  |         |
+        +---------+---------+      
+
+    */
+    #define VIRTUAL_MATRIX_CHAIN_TYPE CHAIN_BOTTOM_LEFT_UP 
+
+// 3) Create the runtime objects to use
 
     // placeholder for the matrix object
     MatrixPanel_I2S_DMA *dma_display = nullptr;
@@ -203,37 +112,58 @@ void setup() {
       Serial.println("****** !KABOOM! I2S memory allocation failed ***********");
 
   // create VirtualDisplay object based on our newly created dma_display object
-  virtualDisp = new VirtualMatrixPanel((*dma_display), NUM_ROWS, NUM_COLS, PANEL_RES_X, PANEL_RES_Y, SERPENT, TOPDOWN);
+  virtualDisp = new VirtualMatrixPanel((*dma_display), NUM_ROWS, NUM_COLS, PANEL_RES_X, PANEL_RES_Y, VIRTUAL_MATRIX_CHAIN_TYPE);
 
   // So far so good, so continue
   virtualDisp->fillScreen(virtualDisp->color444(0, 0, 0));
   virtualDisp->drawDisplayTest(); // draw text numbering on each screen to check connectivity
 
-  delay(3000);
+ // delay(1000);
 
-  Serial.println("Chain of 64x32 panels for this example:");
-  Serial.println("+--------+---------+");
+  Serial.println("Chain of 4x 64x32 panels for this example:");
+  Serial.println("+---------+---------+");
   Serial.println("|    4    |    3    |");
   Serial.println("|         |         |");
-  Serial.println("+--------+---------+");
+  Serial.println("+---------+---------+");
   Serial.println("|    1    |    2    |");
-  Serial.println("| (ESP)  |         |");
-  Serial.println("+--------+---------+");
+  Serial.println("| (ESP32) |         |");
+  Serial.println("+---------+---------+");
 
+   // draw blue text
    virtualDisp->setFont(&FreeSansBold12pt7b);
    virtualDisp->setTextColor(virtualDisp->color565(0, 0, 255));
-   virtualDisp->setTextSize(2); 
-   virtualDisp->setCursor(10, virtualDisp->height()-20); 
+   virtualDisp->setTextSize(3); 
+   virtualDisp->setCursor(0, virtualDisp->height()- ((virtualDisp->height()-45)/2));    
+   virtualDisp->print("ABCD");
 
    // Red text inside red rect (2 pix in from edge)
-   virtualDisp->print("1234");
    virtualDisp->drawRect(1,1, virtualDisp->width()-2, virtualDisp->height()-2, virtualDisp->color565(255,0,0));
 
    // White line from top left to bottom right
    virtualDisp->drawLine(0,0, virtualDisp->width()-1, virtualDisp->height()-1, virtualDisp->color565(255,255,255));
+
+   virtualDisp->drawDisplayTest(); // re draw text numbering on each screen to check connectivity
+   
 }
 
 void loop() {
   
 
 } // end loop
+
+
+/*****************************************************************************
+
+    Thanks to:
+
+    * Brian Lough for the original example as raised in this issue:
+      https://github.com/mrfaptastic/ESP32-HUB75-MatrixPanel-I2S-DMA/issues/26
+
+      YouTube: https://www.youtube.com/brianlough
+      Tindie: https://www.tindie.com/stores/brianlough/
+      Twitter: https://twitter.com/witnessmenow
+
+    * Galaxy-Man for the kind donation of panels make/test that this is possible:
+      https://github.com/Galaxy-Man
+
+*****************************************************************************/

examples/ChainedPanels/README.md

@@ -2,6 +2,8 @@
 
 This is the PatternPlasma Demo adopted for use with multiple LED Matrix Panel displays arranged in a non standard order (i.e. a grid) to make a bigger display.
 
+![334894846_975082690567510_1362796919784291270_n](https://user-images.githubusercontent.com/89576620/224304944-94fe3483-d3cc-4aba-be0a-40b33ff901dc.jpg)
+
 ### What do we mean by 'non standard order'? ###
 
 When you link / chain multiple panels together, the ESP32-HUB75-MatrixPanel-I2S-DMA library treats as one wide horizontal panel. This would be a 'standard' (default) order.
@@ -10,12 +12,12 @@ Non-standard order is essentially the creation of a non-horizontal-only display
 
 For example: You bought four (4) 64x32px panels, and wanted to use them to create a 128x64pixel display. You would use the VirtualMatrixPanel class.
 
-[Refer to this document](VirtualMatrixPanel.pdf) for an explanation and refer to this example on how to use.
+[Refer to this document](https://github.com/mrfaptastic/ESP32-HUB75-MatrixPanel-DMA/blob/master/doc/VirtualMatrixPanel.pdf) for an explanation and refer to this example on how to use.
 
 
 ### Steps to Use ###
 
-1. [Refer to this document](VirtualMatrixPanel.pdf) for an explanation and refer to this example on how to use.
+1. [Refer to this document](https://github.com/mrfaptastic/ESP32-HUB75-MatrixPanel-DMA/blob/master/doc/VirtualMatrixPanel.pdf) for an explanation and refer to this example on how to use.
 
 2. In your Arduino sketch, configure these defines accordingly:
 ```
@@ -24,7 +26,15 @@ For example: You bought four (4) 64x32px panels, and wanted to use them to creat
 
 #define NUM_ROWS 2 // Number of rows of chained INDIVIDUAL PANELS
 #define NUM_COLS 2 // Number of INDIVIDUAL PANELS per ROW
+
+#define PANEL_CHAIN NUM_ROWS*NUM_COLS    // total number of panels chained one to another
+
+#define VIRTUAL_MATRIX_CHAIN_TYPE <INSERT CHAINING TYPE HERE - Refer to documentation or example>
+	
 ```
+VIRTUAL_MATRIX_CHAIN_TYPE's:
+![image](https://user-images.githubusercontent.com/12006953/224537356-e3c8e87b-0bc0-4185-8f5d-d2d3b328d176.png)
+
 
 3. In your Arduino sketch, use the 'VirtualMatrixPanel' class instance (virtualDisp) to draw to the display (i.e. drawPixel), instead of the underling MatrixPanel_I2S_DMA class instance (dma_display).
 

examples/ChainedPanelsAuroraDemo/ChainedPanelsAuroraDemo.ino

@@ -117,7 +117,7 @@ void setup()
   matrix->setBrightness8(96);    // range is 0-255, 0 - 0%, 255 - 100%
 
   // create VirtualDisplay object based on our newly created dma_display object
-  virtualDisp = new VirtualMatrixPanel((*matrix), NUM_ROWS, NUM_COLS, PANEL_RES_X, PANEL_RES_Y, SERPENT, TOPDOWN);
+  virtualDisp = new VirtualMatrixPanel((*matrix), NUM_ROWS, NUM_COLS, PANEL_RES_X, PANEL_RES_Y, CHAIN_TOP_LEFT_DOWN);
 
   Serial.println("**************** Starting Aurora Effects Demo ****************");
 

examples/Four_Scan_Panel/Four_Scan_Panel.ino

@@ -91,7 +91,7 @@
     delay(500);
     
     // create FourScanPanellay object based on our newly created dma_display object
-    FourScanPanel = new VirtualMatrixPanel((*dma_display), NUM_ROWS, NUM_COLS, PANEL_RES_X, PANEL_RES_Y, SERPENT, TOPDOWN);
+    FourScanPanel = new VirtualMatrixPanel((*dma_display), NUM_ROWS, NUM_COLS, PANEL_RES_X, PANEL_RES_Y);
     
 	// THE IMPORTANT BIT BELOW!
     FourScanPanel->setPhysicalPanelScanRate(FOUR_SCAN_32PX_HIGH);

examples/HueValueSpectrum/HueValueSpectrum.ino

@@ -7,6 +7,10 @@
 MatrixPanel_I2S_DMA *dma_display = nullptr;
 
 void setup() {
+
+  Serial.begin(112500);
+
+
   HUB75_I2S_CFG::i2s_pins _pins={
     25, //R1_PIN, 
     26, //G1_PIN, 
@@ -26,8 +30,8 @@ void setup() {
   HUB75_I2S_CFG mxconfig(
     PANEL_RES_X, // Module width
     PANEL_RES_Y, // Module height
-    PANEL_CHAIN, // chain length
-    _pins // pin mapping
+    PANEL_CHAIN //, // chain length
+    //_pins // pin mapping -- uncomment if providing own custom pin mapping as per above.
   );
   //mxconfig.clkphase = false;
   //mxconfig.driver = HUB75_I2S_CFG::FM6126A;
@@ -40,12 +44,13 @@ void setup() {
 
 void loop() {
   // Canvas loop
-  float t = (float)(millis()%4000)/4000.f;
-  float tt = (float)((millis()%16000)/16000.f;
+  float t = (float) ((millis()%4000)/4000.f);
+  float tt = (float) ((millis()%16000)/16000.f);
 
-  for(int x = 0; x < PANEL_RES_X*PANEL_CHAIN; x++){
+  for(int x = 0; x < (PANEL_RES_X*PANEL_CHAIN); x++)
+  {
     // calculate the overal shade
-    float f = ((sin(tt-(float)x/PANEL_RES_Y/32.)*2.f*PI)+1)/2)*255;
+    float f = (((sin(tt-(float)x/PANEL_RES_Y/32.)*2.f*PI)+1)/2)*255;
     // calculate hue spectrum into rgb
     float r = max(min(cosf(2.f*PI*(t+((float)x/PANEL_RES_Y+0.f)/3.f))+0.5f,1.f),0.f);
     float g = max(min(cosf(2.f*PI*(t+((float)x/PANEL_RES_Y+1.f)/3.f))+0.5f,1.f),0.f);

examples/PIO_TestPatterns/src/main.cpp

@@ -116,7 +116,7 @@ void setup(){
   chain->begin();
   chain->setBrightness8(255);
   // create VirtualDisplay object based on our newly created dma_display object
-  matrix = new VirtualMatrixPanel((*chain), NUM_ROWS, NUM_COLS, PANEL_WIDTH, PANEL_HEIGHT, SERPENT, TOPDOWN);
+  matrix = new VirtualMatrixPanel((*chain), NUM_ROWS, NUM_COLS, PANEL_WIDTH, PANEL_HEIGHT, CHAIN_TOP_LEFT_DOWN);
 #endif
 
   ledbuff = (CRGB *)malloc(NUM_LEDS * sizeof(CRGB));  // allocate buffer for some tests

examples/esp-idf/.gitignore

@@ -0,0 +1,12 @@
+# ESP-IDF default build directory
+build
+
+# Temporary files
+*.swp
+
+# lock files for examples and components
+dependencies.lock
+
+sdkconfig*
+# Unignore sdkconfig.defaults
+!sdkconfig.defaults

examples/esp-idf/with-gfx/CMakeLists.txt

@@ -0,0 +1,10 @@
+# This is a boilerplate top-level project CMakeLists.txt file.
+# This is the primary file which CMake uses to learn how to build the project.
+#
+# Most of the important stuff happens in the 'main' directory.
+#
+# See https://docs.espressif.com/projects/esp-idf/en/latest/esp32/api-guides/build-system.html#example-project for more details.
+cmake_minimum_required(VERSION 3.5)
+
+include($ENV{IDF_PATH}/tools/cmake/project.cmake)
+project(with-gfx)

examples/esp-idf/with-gfx/README.md

@@ -0,0 +1,17 @@
+# ESP-IDF Example With Adafruit GFX Library
+
+This folder contains example code for using this library with `esp-idf` and the [Adafruit GFX library](https://github.com/adafruit/Adafruit-GFX-Library).
+
+First, follow the [Getting Started Guide for ESP-IDF](https://docs.espressif.com/projects/esp-idf/en/latest/esp32/get-started/index.html) to install ESP-IDF onto your computer.
+
+When you are ready to start your first project with this library, follow folow these steps:
+
+  1. Copy the files in this folder (and sub folders) into a new directory for your project.
+  1. Clone the required repositories:
+     ```
+     git clone https://github.com/mrfaptastic/ESP32-HUB75-MatrixPanel-DMA.git components/ESP32-HUB75-MatrixPanel-I2S-DMA
+     git clone https://github.com/adafruit/Adafruit-GFX-Library.git components/Adafruit-GFX-Library
+     git clone https://github.com/adafruit/Adafruit_BusIO.git components/Adafruit_BusIO
+     git clone https://github.com/espressif/arduino-esp32.git components/arduino
+     ```
+  1. Build your project: `idf.py build`

examples/esp-idf/with-gfx/components/.gitignore

@@ -0,0 +1,4 @@
+# Ignore everything in this directory
+*
+# Except this file
+!.gitignore

examples/esp-idf/with-gfx/main/CMakeLists.txt

@@ -0,0 +1,5 @@
+idf_component_register(
+			SRC_DIRS "." ${SRCDIRS}
+			INCLUDE_DIRS ${INCLUDEDIRS}
+			REQUIRES ESP32-HUB75-MatrixPanel-I2S-DMA
+                       )

examples/esp-idf/with-gfx/main/main.cpp

@@ -0,0 +1,14 @@
+#include "ESP32-HUB75-MatrixPanel-I2S-DMA.h"
+
+MatrixPanel_I2S_DMA *dma_display = nullptr;
+
+extern "C" void app_main() {
+  HUB75_I2S_CFG mxconfig(/* width = */ 64, /* height = */ 64, /* chain = */ 1);
+
+  dma_display = new MatrixPanel_I2S_DMA(mxconfig);
+  dma_display->begin();
+  dma_display->setBrightness8(80);
+  dma_display->clearScreen();
+  // `println` is only available when the Adafruit GFX library is used.
+  dma_display->println("Test message");
+}

examples/esp-idf/with-gfx/sdkconfig.defaults

@@ -0,0 +1 @@
+CONFIG_FREERTOS_HZ=1000

examples/esp-idf/without-gfx/CMakeLists.txt

@@ -0,0 +1,10 @@
+# This is a boilerplate top-level project CMakeLists.txt file.
+# This is the primary file which CMake uses to learn how to build the project.
+#
+# Most of the important stuff happens in the 'main' directory.
+#
+# See https://docs.espressif.com/projects/esp-idf/en/latest/esp32/api-guides/build-system.html#example-project for more details.
+cmake_minimum_required(VERSION 3.5)
+
+include($ENV{IDF_PATH}/tools/cmake/project.cmake)
+project(without-gfx)

examples/esp-idf/without-gfx/README.md

@@ -0,0 +1,14 @@
+# ESP-IDF Example Without Adafruit GFX Library
+
+This folder contains example code for using this library with `esp-idf`.
+
+First, follow the [Getting Started Guide for ESP-IDF](https://docs.espressif.com/projects/esp-idf/en/latest/esp32/get-started/index.html) to install ESP-IDF onto your computer.
+
+When you are ready to start your first project with this library, follow folow these steps:
+
+  1. Copy the files in this folder (and sub folders) into a new directory for your project.
+  1. Clone the required repositories:
+     ```
+     git clone https://github.com/mrfaptastic/ESP32-HUB75-MatrixPanel-DMA.git components/ESP32-HUB75-MatrixPanel-I2S-DMA
+     ```
+  1. Build your project: `idf.py build`

examples/esp-idf/without-gfx/components/.gitignore

@@ -0,0 +1,4 @@
+# Ignore everything in this directory
+*
+# Except this file
+!.gitignore

examples/esp-idf/without-gfx/main/CMakeLists.txt

@@ -0,0 +1,5 @@
+idf_component_register(
+			SRC_DIRS "." ${SRCDIRS}
+			INCLUDE_DIRS ${INCLUDEDIRS}
+			REQUIRES ESP32-HUB75-MatrixPanel-I2S-DMA
+                       )

examples/esp-idf/without-gfx/main/main.cpp

@@ -0,0 +1,12 @@
+#include "ESP32-HUB75-MatrixPanel-I2S-DMA.h"
+
+MatrixPanel_I2S_DMA *dma_display = nullptr;
+
+extern "C" void app_main() {
+  HUB75_I2S_CFG mxconfig(/* width = */ 64, /* height = */ 64, /* chain = */ 1);
+
+  dma_display = new MatrixPanel_I2S_DMA(mxconfig);
+  dma_display->begin();
+  dma_display->setBrightness8(80);
+  dma_display->clearScreen();
+}

examples/esp-idf/without-gfx/sdkconfig.defaults

@@ -0,0 +1 @@
+CONFIG_ESP32_HUB75_USE_GFX=n

library.json

@@ -1,6 +1,6 @@
 {
     "name": "ESP32 HUB75 LED MATRIX PANEL DMA Display",
-    "version": "3.0.5",
+    "version": "3.0.9",
     "description": "An Adafruit GFX compatible library for LED matrix modules which uses DMA for ultra-fast refresh rates and therefore very low CPU usage.",
     "keywords": "hub75, esp32, esp32s2, esp32s3, display, dma, rgb matrix",
     "repository": {

library.properties

@@ -1,5 +1,5 @@
 name=ESP32 HUB75 LED MATRIX PANEL DMA Display
-version= 3.0.5
+version= 3.0.9
 author=Faptastic
 maintainer=Faptastic 
 sentence=HUB75 LED Matrix Library for ESP32, ESP32-S2 and ESP32-S3

src/ESP32-HUB75-MatrixPanel-I2S-DMA.cpp

@@ -10,7 +10,10 @@
  * when used in tight loops while method from struct could be flushed out of instruction cache between
  * loop cycles do NOT forget about buff_id param if using this.
  */
-#define getRowDataPtr(row, _dpth, buff_id) &(dma_buff.rowBits[row]->data[_dpth * dma_buff.rowBits[row]->width + buff_id*(dma_buff.rowBits[row]->width * dma_buff.rowBits[row]->colour_depth)])
+// #define getRowDataPtr(row, _dpth, buff_id) &(dma_buff.rowBits[row]->data[_dpth * dma_buff.rowBits[row]->width + buff_id*(dma_buff.rowBits[row]->width * dma_buff.rowBits[row]->colour_depth)])
+
+// BufferID is now ignored, seperate global pointer pointer!
+#define getRowDataPtr(row, _dpth, buff_id) &(fb->rowBits[row]->data[_dpth * fb->rowBits[row]->width])
 
 /* We need to update the correct uint16_t in the rowBitStruct array, that gets sent out in parallel
  * 16 bit parallel mode - Save the calculated value to the bitplane memory in reverse order to account for I2S Tx FIFO mode1 ordering
@@ -27,25 +30,7 @@
  * However, if the library is to be used with lower colour depth (i.e. 6 bit colour), then we need to ensure the 8-bit value passed to the colour masking
  * is adjusted accordingly to ensure the LSB's are shifted left to MSB, by the difference. Otherwise the colours will be all screwed up.
  */
-//#if PIXEL_COLOR_DEPTH_BITS > 12
-//    #error "Color depth bits cannot be greater than 12."
-//#elif PIXEL_COLOR_DEPTH_BITS < 2 
-//    #error "Color depth bits cannot be less than 2."
-//#endif
-
-  //#define MASK_OFFSET (16 - PIXEL_COLOR_DEPTH_BITS)
-  //#define PIXEL_COLOR_MASK_BIT(color_depth_index)   (1 << (color_depth_index + MASK_OFFSET))
 #define PIXEL_COLOR_MASK_BIT(color_depth_index, mask_offset) (1 << (color_depth_index + mask_offset))
-  //static constexpr uint8_t const MASK_OFFSET = 8-PIXEL_COLOUR_DEPTH_BITS;
-
-/*
-    #if PIXEL_COLOR_DEPTH_BITS < 8
-        uint8_t mask = (1 << (colour_depth_idx+MASK_OFFSET)); // expect 24 bit colour (8 bits per RGB subpixel)
-    #else
-        uint8_t mask = (1 << (colour_depth_idx)); // expect 24 bit colour (8 bits per RGB subpixel)
-    #endif 
-*/
-
 
 bool MatrixPanel_I2S_DMA::allocateDMAmemory()
 {
@@ -53,15 +38,18 @@ bool MatrixPanel_I2S_DMA::allocateDMAmemory()
   ESP_LOGI("I2S-DMA", "Free heap: %d", heap_caps_get_free_size(MALLOC_CAP_INTERNAL));
   ESP_LOGI("I2S-DMA", "Free SPIRAM: %d", heap_caps_get_free_size(MALLOC_CAP_SPIRAM));
 
-
   // Alright, theoretically we should be OK, so let us do this, so
   // lets allocate a chunk of memory for each row (a row could span multiple panels if chaining is in place)
-  dma_buff.rowBits.reserve(ROWS_PER_FRAME);
-
   ESP_LOGI("I2S-DMA", "allocating rowBitStructs with pixel_color_depth_bits of %d", m_cfg.getPixelColorDepthBits());
   // iterate through number of rows, allocate memory for each
   size_t allocated_fb_memory = 0;
-    for (int malloc_num =0; malloc_num < ROWS_PER_FRAME; ++malloc_num)
+
+  int fbs_required = (m_cfg.double_buff) ? 2 : 1;
+  for (int fb = 0; fb < (fbs_required); fb++)
+  {
+    frame_buffer[fb].rowBits.reserve(ROWS_PER_FRAME);
+
+    for (int malloc_num = 0; malloc_num < ROWS_PER_FRAME; malloc_num++)
     {
       auto ptr = std::make_shared<rowBitStruct>(PIXELS_PER_ROW, m_cfg.getPixelColorDepthBits(), m_cfg.double_buff);
 
@@ -74,18 +62,23 @@ bool MatrixPanel_I2S_DMA::allocateDMAmemory()
         // TODO: should we release all previous rowBitStructs here???
       }
 
-        allocated_fb_memory += ptr->size();
-        dma_buff.rowBits.emplace_back(ptr);     // save new rowBitStruct into rows vector
-        ++dma_buff.rows;
+      allocated_fb_memory += ptr->getColorDepthSize(); // byte required to display all colour depths for the rows shown at the same time
+      frame_buffer[fb].rowBits.emplace_back(ptr); // save new rowBitStruct pointer into rows vector
+      ++frame_buffer[fb].rows;
+    }
   }
   ESP_LOGI("I2S-DMA", "Allocating %d bytes memory for DMA BCM framebuffer(s).", allocated_fb_memory);
 
   // calculate the lowest LSBMSB_TRANSITION_BIT value that will fit in memory that will meet or exceed the configured refresh rate
+  
+//#define FORCE_COLOR_DEPTH 1
+  
 #if !defined(FORCE_COLOR_DEPTH)
 
   ESP_LOGI("I2S-DMA", "Minimum visual refresh rate (scan rate from panel top to bottom) requested: %d Hz", m_cfg.min_refresh_rate);
 
-    while(1) {           
+  while (1)
+  {
     int psPerClock = 1000000000000UL / m_cfg.i2sspeed;
     int nsPerLatch = ((PIXELS_PER_ROW + CLKS_DURING_LATCH) * psPerClock) / 1000;
 
@@ -120,13 +113,13 @@ bool MatrixPanel_I2S_DMA::allocateDMAmemory()
 
 #endif
 
-
   /***
    * Step 2a: lsbMsbTransition bit is now finalised - recalculate the DMA descriptor count required, which is used for
    *          memory allocation of the DMA linked list memory structure.
    */
   int numDMAdescriptorsPerRow = 1;
-    for(int i=lsbMsbTransitionBit + 1; i < m_cfg.getPixelColorDepthBits(); i++) {
+  for (int i = lsbMsbTransitionBit + 1; i < m_cfg.getPixelColorDepthBits(); i++)
+  {
     numDMAdescriptorsPerRow += (1 << (i - lsbMsbTransitionBit - 1));
   }
 
@@ -134,7 +127,7 @@ bool MatrixPanel_I2S_DMA::allocateDMAmemory()
 
   // Refer to 'DMA_LL_PAYLOAD_SPLIT' code in configureDMA() below to understand why this exists.
   // numDMAdescriptorsPerRow is also used to calculate descount which is super important in i2s_parallel_config_t SoC DMA setup.
-    if ( dma_buff.rowBits[0]->size() > DMA_MAX ) 
+  if (frame_buffer[0].rowBits[0]->getColorDepthSize() > DMA_MAX)
   {
 
     ESP_LOGW("I2S-DMA", "rowBits struct is too large to fit in one DMA transfer payload, splitting required. Adding %d DMA descriptors\n", m_cfg.getPixelColorDepthBits() - 1);
@@ -143,19 +136,23 @@ bool MatrixPanel_I2S_DMA::allocateDMAmemory()
     // Note: If numDMAdescriptorsPerRow is even just one descriptor too large, DMA linked list will not correctly loop.
   }
 
-
   /***
    * Step 3: Allocate memory for DMA linked list, linking up each framebuffer row in sequence for GPIO output.
    */
 
   // malloc the DMA linked list descriptors that i2s_parallel will need
-    desccount = numDMAdescriptorsPerRow * ROWS_PER_FRAME;
+  int desccount = numDMAdescriptorsPerRow * ROWS_PER_FRAME;
 
   if (m_cfg.double_buff)
+  {
     dma_bus.enable_double_dma_desc();
+  }
 
   dma_bus.allocate_dma_desc_memory(desccount);
 
+  // point FB we can write to, to 0 / dmadesc_a
+  fb = &frame_buffer[0];
+
   // Just os we know
   initialized = true;
 
@@ -165,6 +162,31 @@ bool MatrixPanel_I2S_DMA::allocateDMAmemory()
 
 
 
+/*
+// Version 2.0 March 2023 
+int MatrixPanel_I2S_DMA::create_descriptor_links(void *data, size_t size, bool dmadesc_b, bool countonly)
+{
+    int len = size;
+    uint8_t *data2 = (uint8_t *)data;
+
+    int n = 0;    
+    while (len)
+    {
+        int dmalen = len;
+        if (dmalen > DMA_MAX)
+            dmalen = DMA_MAX;
+
+          if (!countonly)
+            dma_bus.create_dma_desc_link(data2, dmalen, dmadesc_b);                
+
+        len -= dmalen;
+        data2 += dmalen;
+        n++;
+    }
+
+    return n;
+}
+*/
 void MatrixPanel_I2S_DMA::configureDMA(const HUB75_I2S_CFG &_cfg)
 {
 
@@ -174,11 +196,13 @@ void MatrixPanel_I2S_DMA::configureDMA(const HUB75_I2S_CFG& _cfg)
 
   // HACK: If we need to split the payload in 1/2 so that it doesn't breach DMA_MAX, lets do it by the colour_depth.
   int num_dma_payload_colour_depths = m_cfg.getPixelColorDepthBits();
-    if ( dma_buff.rowBits[0]->size() > DMA_MAX ) {
+  if (frame_buffer[0].rowBits[0]->getColorDepthSize() > DMA_MAX)
+  {
     num_dma_payload_colour_depths = 1;
   }
 
-    // Fill DMA linked lists for both frames (as in, halves of the HUB75 panel) and if double buffering is enabled, link it up for both buffers.
+
+ // Fill DMA linked lists for both frames (as in, halves of the HUB75 panel) in sequence (top to bottom) 
   for (int row = 0; row < ROWS_PER_FRAME; row++)
   {
     // first set of data is LSB through MSB, single pass (IF TOTAL SIZE < DMA_MAX) - all colour bits are displayed once, which takes care of everything below and including LSBMSB_TRANSITION_BIT
@@ -186,25 +210,26 @@ void MatrixPanel_I2S_DMA::configureDMA(const HUB75_I2S_CFG& _cfg)
     // link_dma_desc(&dmadesc_a[current_dmadescriptor_offset], previous_dmadesc_a, dma_buff.rowBits[row]->getDataPtr(), dma_buff.rowBits[row]->size(num_dma_payload_colour_depths));
     //   previous_dmadesc_a = &dmadesc_a[current_dmadescriptor_offset];
 
-        dma_bus.create_dma_desc_link(dma_buff.rowBits[row]->getDataPtr(0, 0), dma_buff.rowBits[row]->size(num_dma_payload_colour_depths), false);
+    dma_bus.create_dma_desc_link(frame_buffer[0].rowBits[row]->getDataPtr(0, 0), frame_buffer[0].rowBits[row]->getColorDepthSize(), false);
 
     if (m_cfg.double_buff)
     {
-          dma_bus.create_dma_desc_link(dma_buff.rowBits[row]->getDataPtr(0, 1), dma_buff.rowBits[row]->size(num_dma_payload_colour_depths), true);          
+      dma_bus.create_dma_desc_link(frame_buffer[1].rowBits[row]->getDataPtr(0, 1), frame_buffer[1].rowBits[row]->getColorDepthSize(), true);
     }
 
     current_dmadescriptor_offset++;
 
     // If the number of pixels per row is too great for the size of a DMA payload, so we need to split what we were going to send above.
-        if ( dma_buff.rowBits[0]->size() > DMA_MAX )
+    if (frame_buffer[0].rowBits[0]->getColorDepthSize() > DMA_MAX)
     {
 
       for (int cd = 1; cd < m_cfg.getPixelColorDepthBits(); cd++)
       {
-            dma_bus.create_dma_desc_link(dma_buff.rowBits[row]->getDataPtr(cd, 0), dma_buff.rowBits[row]->size(num_dma_payload_colour_depths), false);            
+        dma_bus.create_dma_desc_link(frame_buffer[0].rowBits[row]->getDataPtr(cd, 0), frame_buffer[0].rowBits[row]->getColorDepthSize(1), false);
 
-            if (m_cfg.double_buff) {
-              dma_bus.create_dma_desc_link(dma_buff.rowBits[row]->getDataPtr(cd, 1), dma_buff.rowBits[row]->size(num_dma_payload_colour_depths), true);            
+        if (m_cfg.double_buff)
+        {
+          dma_bus.create_dma_desc_link(frame_buffer[1].rowBits[row]->getDataPtr(cd, 1), frame_buffer[1].rowBits[row]->getColorDepthSize(1), true);
         }
 
         current_dmadescriptor_offset++;
@@ -212,7 +237,6 @@ void MatrixPanel_I2S_DMA::configureDMA(const HUB75_I2S_CFG& _cfg)
       } // additional linked list items
     }   // row depth struct
 
-
     for (int i = lsbMsbTransitionBit + 1; i < m_cfg.getPixelColorDepthBits(); i++)
     {
       // binary time division setup: we need 2 of bit (LSBMSB_TRANSITION_BIT + 1) four of (LSBMSB_TRANSITION_BIT + 2), etc
@@ -221,10 +245,11 @@ void MatrixPanel_I2S_DMA::configureDMA(const HUB75_I2S_CFG& _cfg)
 
       for (int k = 0; k < (1 << (i - lsbMsbTransitionBit - 1)); k++)
       {
-                dma_bus.create_dma_desc_link(dma_buff.rowBits[row]->getDataPtr(i, 0),  dma_buff.rowBits[row]->size(m_cfg.getPixelColorDepthBits() - i), false);
+        dma_bus.create_dma_desc_link(frame_buffer[0].rowBits[row]->getDataPtr(i, 0), frame_buffer[0].rowBits[row]->getColorDepthSize(1), false);
 
-                if (m_cfg.double_buff) {
-                  dma_bus.create_dma_desc_link(dma_buff.rowBits[row]->getDataPtr(i, 1),  dma_buff.rowBits[row]->size(m_cfg.getPixelColorDepthBits() - i), true );
+        if (m_cfg.double_buff)
+        {
+          dma_bus.create_dma_desc_link(frame_buffer[1].rowBits[row]->getDataPtr(i, 1), frame_buffer[1].rowBits[row]->getColorDepthSize(1), true);
         }
 
         current_dmadescriptor_offset++;
@@ -242,7 +267,8 @@ void MatrixPanel_I2S_DMA::configureDMA(const HUB75_I2S_CFG& _cfg)
   auto bus_cfg = dma_bus.config(); // バス設定用の構造体を取得します。
 
   bus_cfg.bus_freq    = m_cfg.i2sspeed;
-      bus_cfg.pin_wr   = m_cfg.gpio.clk;      // WR を接続しているピン番号
+  bus_cfg.pin_wr      = m_cfg.gpio.clk;
+  bus_cfg.invert_pclk = m_cfg.clkphase;
 
   bus_cfg.pin_d0 = m_cfg.gpio.r1;
   bus_cfg.pin_d1 = m_cfg.gpio.g1;
@@ -278,7 +304,6 @@ void MatrixPanel_I2S_DMA::configureDMA(const HUB75_I2S_CFG& _cfg)
 
 } // end initMatrixDMABuff
 
-
 /* There are 'bits' set in the frameStruct that we simply don't need to set every single time we change a pixel / DMA buffer co-ordinate.
  *  For example, the bits that determine the address lines, we don't need to set these every time. Once they're in place, and assuming we
  *  don't accidentally clear them, then we don't need to set them again.
@@ -300,12 +325,14 @@ void MatrixPanel_I2S_DMA::configureDMA(const HUB75_I2S_CFG& _cfg)
  */
 void IRAM_ATTR MatrixPanel_I2S_DMA::updateMatrixDMABuffer(uint16_t x_coord, uint16_t y_coord, uint8_t red, uint8_t green, uint8_t blue)
 {
-    if ( !initialized ) return;
+  if (!initialized)
+    return;
 
   /* 1) Check that the co-ordinates are within range, or it'll break everything big time.
    * Valid co-ordinates are from 0 to (MATRIX_XXXX-1)
    */
-  if ( x_coord >= PIXELS_PER_ROW || y_coord >= m_cfg.mx_height) {
+  if (x_coord >= PIXELS_PER_ROW || y_coord >= m_cfg.mx_height)
+  {
     return;
   }
 
@@ -320,9 +347,9 @@ uint16_t red16, green16, blue16;
   green16 = lumConvTab[green];
   blue16 = lumConvTab[blue];
 #else
-    red16   = red << 8;
-    green16 = green << 8;
-    blue16  = blue << 8;
+  red16 = red << 8 | red;
+  green16 = green << 8 | green;
+  blue16 = blue << 8 | blue;
 #endif
 
   /* When using the drawPixel, we are obviously only changing the value of one x,y position,
@@ -336,20 +363,12 @@ uint16_t red16, green16, blue16;
    * so we have to check for this and check the correct position of the MATRIX_DATA_STORAGE_TYPE
    * data.
    */
-/*
-#if defined (ESP32_THE_ORIG)
-    // We need to update the correct uint16_t in the rowBitStruct array, that gets sent out in parallel
-    // 16 bit parallel mode - Save the calculated value to the bitplane memory in reverse order to account for I2S Tx FIFO mode1 ordering
-    // Irrelevant for ESP32-S2 the way the FIFO ordering works is different - refer to page 679 of S2 technical reference manual
-    x_coord & 1U ? --x_coord : ++x_coord;
-#endif 
-*/
   x_coord = ESP32_TX_FIFO_POSITION_ADJUST(x_coord);
 
-    
   uint16_t _colourbitclear = BITMASK_RGB1_CLEAR, _colourbitoffset = 0;
 
-    if (y_coord >= ROWS_PER_FRAME){    // if we are drawing to the bottom part of the panel
+  if (y_coord >= ROWS_PER_FRAME)
+  { // if we are drawing to the bottom part of the panel
     _colourbitoffset = BITS_RGB2_OFFSET;
     _colourbitclear = BITMASK_RGB2_CLEAR;
     y_coord -= ROWS_PER_FRAME;
@@ -357,16 +376,10 @@ uint16_t red16, green16, blue16;
 
   // Iterating through colour depth bits, which we assume are 8 bits per RGB subpixel (24bpp)
   uint8_t colour_depth_idx = m_cfg.getPixelColorDepthBits();
-    do {
+  do
+  {
     --colour_depth_idx;
-/*        
-//        uint8_t mask = (1 << (colour_depth_idx COLOR_DEPTH_LESS_THAN_8BIT_ADJUST)); // expect 24 bit colour (8 bits per RGB subpixel)
-    #if PIXEL_COLOUR_DEPTH_BITS < 8
-        uint8_t mask = (1 << (colour_depth_idx+MASK_OFFSET)); // expect 24 bit colour (8 bits per RGB subpixel)
-    #else
-        uint8_t mask = (1 << (colour_depth_idx)); // expect 24 bit color (8 bits per RGB subpixel)
-    #endif      
-*/
+
     uint16_t mask = PIXEL_COLOR_MASK_BIT(colour_depth_idx, MASK_OFFSET);
     uint16_t RGB_output_bits = 0;
 
@@ -379,12 +392,10 @@ uint16_t red16, green16, blue16;
     RGB_output_bits |= (bool)(red16 & mask); // BGR
     RGB_output_bits <<= _colourbitoffset;    // shift colour bits to the required position
 
-
     // Get the contents at this address,
     // it would represent a vector pointing to the full row of pixels for the specified colour depth bit at Y coordinate
     ESP32_I2S_DMA_STORAGE_TYPE *p = getRowDataPtr(y_coord, colour_depth_idx, back_buffer_id);
 
-
     // We need to update the correct uint16_t word in the rowBitStruct array pointing to a specific pixel at X - coordinate
     p[x_coord] &= _colourbitclear; // reset RGB bits
     p[x_coord] |= RGB_output_bits; // set new RGB bits
@@ -396,11 +407,11 @@ uint16_t red16, green16, blue16;
   } while (colour_depth_idx); // end of colour depth loop (8)
 } // updateMatrixDMABuffer (specific co-ords change)
 
-
 /* Update the entire buffer with a single specific colour - quicker */
 void MatrixPanel_I2S_DMA::updateMatrixDMABuffer(uint8_t red, uint8_t green, uint8_t blue)
 {
-  if ( !initialized ) return;
+  if (!initialized)
+    return;
 
   /* https://ledshield.wordpress.com/2012/11/13/led-brightness-to-your-eye-gamma-correction-no/ */
   uint16_t red16, green16, blue16;
@@ -418,12 +429,6 @@ uint16_t red16, green16, blue16;
   {
     // let's precalculate RGB1 and RGB2 bits than flood it over the entire DMA buffer
     uint16_t RGB_output_bits = 0;
-//    uint8_t mask = (1 << colour_depth_idx COLOR_DEPTH_LESS_THAN_8BIT_ADJUST); // 24 bit colour
-    // #if PIXEL_COLOR_DEPTH_BITS < 8
-    //     uint8_t mask = (1 << (colour_depth_idx+MASK_OFFSET)); // expect 24 bit colour (8 bits per RGB subpixel)
-    // #else
-    //     uint8_t mask = (1 << (colour_depth_idx)); // expect 24 bit colour (8 bits per RGB subpixel)
-    // #endif      
 
     uint16_t mask = PIXEL_COLOR_MASK_BIT(colour_depth_idx, MASK_OFFSET);
 
@@ -441,21 +446,22 @@ uint16_t red16, green16, blue16;
     // Serial.printf("Fill with: 0x%#06x\n", RGB_output_bits);
 
     // iterate rows
-    int matrix_frame_parallel_row = dma_buff.rowBits.size();
-    do {
+    int matrix_frame_parallel_row = fb->rowBits.size();
+    do
+    {
       --matrix_frame_parallel_row;
 
       // The destination for the pixel row bitstream
       ESP32_I2S_DMA_STORAGE_TYPE *p = getRowDataPtr(matrix_frame_parallel_row, colour_depth_idx, back_buffer_id);
 
       // iterate pixels in a row
-      int x_coord=dma_buff.rowBits[matrix_frame_parallel_row]->width;
-      do { 
+      int x_coord = fb->rowBits[matrix_frame_parallel_row]->width;
+      do
+      {
         --x_coord;
         p[x_coord] &= BITMASK_RGB12_CLEAR; // reset colour bits
         p[x_coord] |= RGB_output_bits;     // set new colour bits
 
-
 #if defined(SPIRAM_DMA_BUFFER)
         Cache_WriteBack_Addr((uint32_t)&p[x_coord], sizeof(ESP32_I2S_DMA_STORAGE_TYPE));
 #endif
@@ -474,64 +480,84 @@ uint16_t red16, green16, blue16;
  * This effectively clears buffers to blank BLACK and makes it ready to display output.
  * (Brightness control via OE bit manipulation is another case) - this must be done as well seperately!
  */
-void MatrixPanel_I2S_DMA::clearFrameBuffer(bool _buff_id){
+void MatrixPanel_I2S_DMA::clearFrameBuffer(bool _buff_id)
+{
   if (!initialized)
     return;
 
+  frameStruct *fb = &frame_buffer[_buff_id];
+
   // we start with iterating all rows in dma_buff structure
-  int row_idx = dma_buff.rowBits.size();
-  do {
+  int row_idx = fb->rowBits.size();
+  do
+  {
     --row_idx;
 
-    ESP32_I2S_DMA_STORAGE_TYPE* row = dma_buff.rowBits[row_idx]->getDataPtr(0, _buff_id);   // set pointer to the HEAD of a buffer holding data for the entire matrix row
+    ESP32_I2S_DMA_STORAGE_TYPE *row = fb->rowBits[row_idx]->getDataPtr(0, -1); // set pointer to the HEAD of a buffer holding data for the entire matrix row
 
     ESP32_I2S_DMA_STORAGE_TYPE abcde = (ESP32_I2S_DMA_STORAGE_TYPE)row_idx;
     abcde <<= BITS_ADDR_OFFSET; // shift row y-coord to match ABCDE bits in vector from 8 to 12
 
     // get last pixel index in a row of all colourdepths
-    int x_pixel = dma_buff.rowBits[row_idx]->width * dma_buff.rowBits[row_idx]->colour_depth;
+    int x_pixel = fb->rowBits[row_idx]->width * fb->rowBits[row_idx]->colour_depth;
     // Serial.printf(" from pixel %d, ", x_pixel);
 
     // fill all x_pixels except colour_index[0] (LSB) ones, this also clears all colour data to 0's black
-    do {
+    do
+    {
       --x_pixel;
 
-      if ( m_cfg.driver == HUB75_I2S_CFG::SM5266P) {
+      if (m_cfg.driver == HUB75_I2S_CFG::SM5266P)
+      {
         // modifications here for row shift register type SM5266P
         // https://github.com/mrfaptastic/ESP32-HUB75-MatrixPanel-I2S-DMA/issues/164
         row[x_pixel] = abcde & (0x18 << BITS_ADDR_OFFSET); // mask out the bottom 3 bits which are the clk di bk inputs
-      } else {        
+      }
+      else if (m_cfg.driver == HUB75_I2S_CFG::DP3246_SM5368) 
+      {
+        row[ESP32_TX_FIFO_POSITION_ADJUST(x_pixel)] = 0x0000;
+      }
+      else
+      {
         row[ESP32_TX_FIFO_POSITION_ADJUST(x_pixel)] = abcde;
       }
-   //   ESP_LOGI("", "x pixel 1: %d", x_pixel);
-    } while(x_pixel!=dma_buff.rowBits[row_idx]->width && x_pixel);
+
+    } while (x_pixel != fb->rowBits[row_idx]->width && x_pixel);
 
     // colour_index[0] (LSB) x_pixels must be "marked" with a previous's row address, 'cause  it is used to display
     //  previous row while we pump in LSB's for a new row
     abcde = ((ESP32_I2S_DMA_STORAGE_TYPE)row_idx - 1) << BITS_ADDR_OFFSET;
-    do {
+    do
+    {
       --x_pixel;
 
-      if ( m_cfg.driver == HUB75_I2S_CFG::SM5266P) {
+      if (m_cfg.driver == HUB75_I2S_CFG::SM5266P)
+      {
         // modifications here for row shift register type SM5266P
         // https://github.com/mrfaptastic/ESP32-HUB75-MatrixPanel-I2S-DMA/issues/164
         row[x_pixel] = abcde & (0x18 << BITS_ADDR_OFFSET); // mask out the bottom 3 bits which are the clk di bk inputs
-      } else {        
+      }
+      else if (m_cfg.driver == HUB75_I2S_CFG::DP3246_SM5368) 
+      {
+        row[ESP32_TX_FIFO_POSITION_ADJUST(x_pixel)] = 0x0000;
+      }
+      else
+      {
         row[ESP32_TX_FIFO_POSITION_ADJUST(x_pixel)] = abcde;
       }
-      //row[x_pixel] = abcde;
-  //    ESP_LOGI("", "x pixel 2: %d", x_pixel);
-    } while(x_pixel);
 
+    } while (x_pixel);
 
     // modifications here for row shift register type SM5266P
     // https://github.com/mrfaptastic/ESP32-HUB75-MatrixPanel-I2S-DMA/issues/164
-    if ( m_cfg.driver == HUB75_I2S_CFG::SM5266P) {  
+    if (m_cfg.driver == HUB75_I2S_CFG::SM5266P)
+    {
       uint16_t serialCount;
       uint16_t latch;
-        x_pixel = dma_buff.rowBits[row_idx]->width - 16; // come back 8*2 pixels to allow for 8 writes
+      x_pixel = fb->rowBits[row_idx]->width - 16; // come back 8*2 pixels to allow for 8 writes
       serialCount = 8;
-        do{
+      do
+      {
         serialCount--;
         latch = row[x_pixel] | (((((ESP32_I2S_DMA_STORAGE_TYPE)row_idx) % 8) == serialCount) << 1) << BITS_ADDR_OFFSET; // data on 'B'
         row[x_pixel++] = latch | (0x05 << BITS_ADDR_OFFSET);                                                            // clock high on 'A'and BK high for update
@@ -539,179 +565,85 @@ void MatrixPanel_I2S_DMA::clearFrameBuffer(bool _buff_id){
       } while (serialCount);
     } // end SM5266P
 
+    // row selection for SM5368 shift regs with ABC-only addressing. A is row clk, B is BK and C is row data
+    if (m_cfg.driver == HUB75_I2S_CFG::DP3246_SM5368) 
+    {
+      x_pixel = fb->rowBits[row_idx]->width - 1;                                                                        // last pixel in first block)
+      uint16_t c = (row_idx == 0) ? BIT_C : 0x0000;                                                                     // set row data (C) when row==0, then push through shift regs for all other rows
+      row[ESP32_TX_FIFO_POSITION_ADJUST(x_pixel - 1)] |= c;                                                             // set row data
+      row[ESP32_TX_FIFO_POSITION_ADJUST(x_pixel + 0)] |= c | BIT_A | BIT_B;                                             // set row clk and bk, carry row data
+    } // end DP3246_SM5368
 
     // let's set LAT/OE control bits for specific pixels in each colour_index subrows
     // Need to consider the original ESP32's (WROOM) DMA TX FIFO reordering of bytes...
-    uint8_t colouridx = dma_buff.rowBits[row_idx]->colour_depth;
-    do {
+    uint8_t colouridx = fb->rowBits[row_idx]->colour_depth;
+    do
+    {
       --colouridx;
 
       // switch pointer to a row for a specific colour index
-      row = dma_buff.rowBits[row_idx]->getDataPtr(colouridx, _buff_id);
+      row = fb->rowBits[row_idx]->getDataPtr(colouridx, -1);
 
-      /*
-      #if defined(ESP32_THE_ORIG)
-        // We need to update the correct uint16_t in the rowBitStruct array, that gets sent out in parallel
-        // 16 bit parallel mode - Save the calculated value to the bitplane memory in reverse order to account for I2S Tx FIFO mode1 ordering
-        // Irrelevant for ESP32-S2 the way the FIFO ordering works is different - refer to page 679 of S2 technical reference manual
-        row[dma_buff.rowBits[row_idx]->width - 2] |= BIT_LAT;   // -2 in the DMA array is actually -1 when it's reordered by TX FIFO                  
-      #else
-        // -1 works better on ESP32-S2 ? Because bytes get sent out in order...
-        row[dma_buff.rowBits[row_idx]->width - 1] |= BIT_LAT;   // -1 pixel to compensate array index starting at 0                 
-      #endif
-      */
-      row[ESP32_TX_FIFO_POSITION_ADJUST(dma_buff.rowBits[row_idx]->width - 1)] |= BIT_LAT;   // -1 pixel to compensate array index starting at 0     
+      // DP3246 needs the latch high for 3 clock cycles, so start 2 cycles earlier
+      if (m_cfg.driver == HUB75_I2S_CFG::DP3246_SM5368) 
+      {
+        row[ESP32_TX_FIFO_POSITION_ADJUST(fb->rowBits[row_idx]->width - 3)] |= BIT_LAT;   // DP3246 needs 3 clock cycle latch 
+        row[ESP32_TX_FIFO_POSITION_ADJUST(fb->rowBits[row_idx]->width - 2)] |= BIT_LAT;   // DP3246 needs 3 clock cycle latch 
+      } // DP3246_SM5368
+      
+      row[ESP32_TX_FIFO_POSITION_ADJUST(fb->rowBits[row_idx]->width - 1)] |= BIT_LAT; // -1 pixel to compensate array index starting at 0
 
       // ESP32_TX_FIFO_POSITION_ADJUST(dma_buff.rowBits[row_idx]->width - 1)
 
       // need to disable OE before/after latch to hide row transition
       // Should be one clock or more before latch, otherwise can get ghosting
       uint8_t _blank = m_cfg.latch_blanking;
-      do {
+      do
+      {
         --_blank;
-      /*
-      #if defined(ESP32_THE_ORIG)  
-            // Original ESP32 WROOM FIFO Ordering Sucks
-            uint8_t _blank_row_tx_fifo_tmp = 0 + _blank;
-            (_blank_row_tx_fifo_tmp & 1U) ? --_blank_row_tx_fifo_tmp : ++_blank_row_tx_fifo_tmp; 
-            row[_blank_row_tx_fifo_tmp] |= BIT_OE;
-            
-            _blank_row_tx_fifo_tmp = dma_buff.rowBits[row_idx]->width - _blank - 1; // (LAT pulse is (width-2) -1 pixel to compensate array index starting at 0
-            (_blank_row_tx_fifo_tmp & 1U) ? --_blank_row_tx_fifo_tmp : ++_blank_row_tx_fifo_tmp; 
-            row[_blank_row_tx_fifo_tmp] |= BIT_OE;
-      #else      
-            row[0 + _blank] |= BIT_OE;
-            row[dma_buff.rowBits[row_idx]->width - _blank - 1 ] |= BIT_OE;    // (LAT pulse is (width-2) -1 pixel to compensate array index starting at 0
-      #endif
-      */
 
         row[ESP32_TX_FIFO_POSITION_ADJUST(0 + _blank)] |= BIT_OE;                               // disable output
-	  row[ESP32_TX_FIFO_POSITION_ADJUST(dma_buff.rowBits[row_idx]->width - 1)] |= BIT_OE; // disable output
-      row[ESP32_TX_FIFO_POSITION_ADJUST(dma_buff.rowBits[row_idx]->width - _blank - 1)] |= BIT_OE;    // (LAT pulse is (width-2) -1 pixel to compensate array index starting at 0
-
+        row[ESP32_TX_FIFO_POSITION_ADJUST(fb->rowBits[row_idx]->width - 1)] |= BIT_OE;          // disable output
+        row[ESP32_TX_FIFO_POSITION_ADJUST(fb->rowBits[row_idx]->width - _blank - 1)] |= BIT_OE; // (LAT pulse is (width-2) -1 pixel to compensate array index starting at 0
 
       } while (_blank);
 
     } while (colouridx);
 
-
-
 #if defined(SPIRAM_DMA_BUFFER)
-        Cache_WriteBack_Addr((uint32_t)row, sizeof(ESP32_I2S_DMA_STORAGE_TYPE) * ((dma_buff.rowBits[row_idx]->width * dma_buff.rowBits[row_idx]->colour_depth)-1)) ;
+    Cache_WriteBack_Addr((uint32_t)row, fb->rowBits[row_idx]->getColorDepthSize());
 #endif
 
-
   } while (row_idx);
 }
 
-/**
- * @brief - reset OE bits in DMA buffer in a way to control brightness
- * @param brt - brightness level from 0 to row_width
- * @param _buff_id - buffer id to control
- */
-/* 
-// Depreciated
-void MatrixPanel_I2S_DMA::brtCtrlOE(int brt, const bool _buff_id){
-
-  if (!initialized)
-    return;
-
-  if (brt > PIXELS_PER_ROW - (MAX_LAT_BLANKING + 2))   // can't control values larger than (row_width - latch_blanking) to avoid ongoing issues being raised about brightness and ghosting.
-    brt = PIXELS_PER_ROW   - (MAX_LAT_BLANKING + 2);   // +2 for a bit of buffer...
-
-  if (brt < 0)
-    brt = 0;
-
-  // start with iterating all rows in dma_buff structure
-  int row_idx = dma_buff.rowBits.size();
-  do {
-    --row_idx;
-
-    // let's set OE control bits for specific pixels in each colour_index subrows
-    uint8_t colouridx = dma_buff.rowBits[row_idx]->colour_depth;
-    do {
-      --colouridx;
-
-      // switch pointer to a row for a specific colour index
-      ESP32_I2S_DMA_STORAGE_TYPE* row = dma_buff.rowBits[row_idx]->getDataPtr(colouridx, _buff_id);
-
-      int x_coord = dma_buff.rowBits[row_idx]->width;
-      do {
-        --x_coord;
-        
-       // clear OE bit for all other pixels
-        row[ESP32_TX_FIFO_POSITION_ADJUST(x_coord)] &= BITMASK_OE_CLEAR;       
-
-        // Brightness control via OE toggle - disable matrix output at specified x_coord
-        if((colouridx > lsbMsbTransitionBit || !colouridx) && ((x_coord) >= brt)){
-          row[ESP32_TX_FIFO_POSITION_ADJUST(x_coord)] |= BIT_OE; // Disable output after this point.
-          continue;  
-        }
-        // special case for the bits *after* LSB through (lsbMsbTransitionBit) - OE is output after data is shifted, so need to set OE to fractional brightness
-        if(colouridx && colouridx <= lsbMsbTransitionBit) {
-            // divide brightness in half for each bit below lsbMsbTransitionBit
-            int lsbBrightness = brt >> (lsbMsbTransitionBit - colouridx + 1);
-            if((x_coord) >= lsbBrightness) {
-                row[ESP32_TX_FIFO_POSITION_ADJUST(x_coord)] |= BIT_OE;  // Disable output after this point.
-                continue;
-            }
-        }
-
- 
-      } while(x_coord);
-
-      // need to disable OE before/after latch to hide row transition
-      // Should be one clock or more before latch, otherwise can get ghosting
-      uint8_t _blank = m_cfg.latch_blanking;
-      do {
-        --_blank;
-
-
-      row[ESP32_TX_FIFO_POSITION_ADJUST(0 + _blank)] |= BIT_OE;    
-      
-
-
-        //row[0 + _blank] |= BIT_OE;
-        // no need, has been done already
-        //row[dma_buff.rowBits[row_idx]->width - _blank - 3 ] |= BIT_OE;    // (LAT pulse is (width-2) -1 pixel to compensate array index starting at 0
-      } while (_blank);
-
-    } while(colouridx);
-
-    // switch pointer to a row for a specific colour index
-    #if defined(SPIRAM_DMA_BUFFER)          
-        ESP32_I2S_DMA_STORAGE_TYPE* row_hack = dma_buff.rowBits[row_idx]->getDataPtr(colouridx, _buff_id);    
-        Cache_WriteBack_Addr((uint32_t)row_hack, sizeof(ESP32_I2S_DMA_STORAGE_TYPE) * ((dma_buff.rowBits[row_idx]->width * dma_buff.rowBits[row_idx]->colour_depth)-1)) ;
-    #endif 
-
-
-  } while(row_idx);
-}
-  */
-
-
 /**
  * @brief - reset OE bits in DMA buffer in a way to control brightness
  * @param brt - brightness level from 0 to 255 - NOT MATRIX_WIDTH
  * @param _buff_id - buffer id to control
  */
-void MatrixPanel_I2S_DMA::brtCtrlOEv2(uint8_t brt, const int _buff_id) {
+void MatrixPanel_I2S_DMA::brtCtrlOEv2(uint8_t brt, const int _buff_id)
+{
 
   if (!initialized)
     return;
 
+  frameStruct *fb = &frame_buffer[_buff_id];
+
   uint8_t _blank = m_cfg.latch_blanking; // don't want to inadvertantly blast over this
-  uint8_t _depth = dma_buff.rowBits[0]->colour_depth;
-  uint16_t _width = dma_buff.rowBits[0]->width;
+  uint8_t _depth = fb->rowBits[0]->colour_depth;
+  uint16_t _width = fb->rowBits[0]->width;
 
   // start with iterating all rows in dma_buff structure
-  int row_idx = dma_buff.rowBits.size();
-  do {
+  int row_idx = fb->rowBits.size();
+  do
+  {
     --row_idx;
 
     // let's set OE control bits for specific pixels in each color_index subrows
     uint8_t colouridx = _depth;
-    do {
+    do
+    {
       --colouridx;
 
       char bitplane = (2 * _depth - colouridx) % _depth;
@@ -723,13 +655,14 @@ void MatrixPanel_I2S_DMA::brtCtrlOEv2(uint8_t brt, const int _buff_id) {
       brightness_in_x_pixels = (brightness_in_x_pixels >> 1) | (brightness_in_x_pixels & 1);
 
       // switch pointer to a row for a specific color index
-      ESP32_I2S_DMA_STORAGE_TYPE* row = dma_buff.rowBits[row_idx]->getDataPtr(colouridx, _buff_id);
+      ESP32_I2S_DMA_STORAGE_TYPE *row = fb->rowBits[row_idx]->getDataPtr(colouridx, _buff_id);
 
       // define range of Output Enable on the center of the row
       int x_coord_max = (_width + brightness_in_x_pixels + 1) >> 1;
       int x_coord_min = (_width - brightness_in_x_pixels + 0) >> 1;
       int x_coord = _width;
-      do {
+      do
+      {
         --x_coord;
 
         // (the check is already including "blanking" )
@@ -742,74 +675,61 @@ void MatrixPanel_I2S_DMA::brtCtrlOEv2(uint8_t brt, const int _buff_id) {
           row[ESP32_TX_FIFO_POSITION_ADJUST(x_coord)] |= BIT_OE; // Disable output after this point.
         }
 
-
-		// Note: Old code below from 'brtCtrlOE'
-		
-		/*		
-        // clear OE bit for all other pixels (that is, turn on output)
-        row[ESP32_TX_FIFO_POSITION_ADJUST(x_coord)] &= BITMASK_OE_CLEAR;       
-		
-
-        // Brightness control via OE toggle - disable matrix output at specified x_coord
-        if((colouridx > lsbMsbTransitionBit || !colouridx) && ((x_coord) >= brt)){
-          row[ESP32_TX_FIFO_POSITION_ADJUST(x_coord)] |= BIT_OE; // Disable output after this point.
-          continue;  
-        }
-        // special case for the bits *after* LSB through (lsbMsbTransitionBit) - OE is output after data is shifted, so need to set OE to fractional brightness
-        if(colouridx && colouridx <= lsbMsbTransitionBit) {
-            // divide brightness in half for each bit below lsbMsbTransitionBit
-            int lsbBrightness = brt >> (lsbMsbTransitionBit - colouridx + 1);
-            if((x_coord) >= lsbBrightness) {
-                row[ESP32_TX_FIFO_POSITION_ADJUST(x_coord)] |= BIT_OE;  // Disable output after this point.
-                continue;
-            }
-        }
-		*/
- 
       } while (x_coord);
 
     } while (colouridx);
 
 // switch pointer to a row for a specific colour index
 #if defined(SPIRAM_DMA_BUFFER)
-        ESP32_I2S_DMA_STORAGE_TYPE* row_hack = dma_buff.rowBits[row_idx]->getDataPtr(colouridx, _buff_id);    
-        Cache_WriteBack_Addr((uint32_t)row_hack, sizeof(ESP32_I2S_DMA_STORAGE_TYPE) * ((dma_buff.rowBits[row_idx]->width * dma_buff.rowBits[row_idx]->colour_depth)-1)) ;
+    ESP32_I2S_DMA_STORAGE_TYPE *row_hack = fb->rowBits[row_idx]->getDataPtr(0, _buff_id);
+    //Cache_WriteBack_Addr((uint32_t)row_hack, sizeof(ESP32_I2S_DMA_STORAGE_TYPE) * ((fb->rowBits[row_idx]->width * fb->rowBits[row_idx]->colour_depth) - 1));
+    Cache_WriteBack_Addr((uint32_t)row_hack, fb->rowBits[row_idx]->getColorDepthSize());
 #endif
   } while (row_idx);
-  
 }
 
-
 /*
  *  overload for compatibility
  */
 
-bool MatrixPanel_I2S_DMA::begin(int r1, int g1, int b1, int r2, int g2, int b2, int a, int b, int c, int d, int e, int lat, int oe, int clk) {
-  if(initialized) return true;
+bool MatrixPanel_I2S_DMA::begin(int r1, int g1, int b1, int r2, int g2, int b2, int a, int b, int c, int d, int e, int lat, int oe, int clk)
+{
+  if (initialized)
+    return true;
   // RGB
-  m_cfg.gpio.r1 = r1; m_cfg.gpio.g1 = g1; m_cfg.gpio.b1 = b1;
-  m_cfg.gpio.r2 = r2; m_cfg.gpio.g2 = g2; m_cfg.gpio.b2 = b2;
+  m_cfg.gpio.r1 = r1;
+  m_cfg.gpio.g1 = g1;
+  m_cfg.gpio.b1 = b1;
+  m_cfg.gpio.r2 = r2;
+  m_cfg.gpio.g2 = g2;
+  m_cfg.gpio.b2 = b2;
 
   // Line Select
-  m_cfg.gpio.a = a; m_cfg.gpio.b = b; m_cfg.gpio.c = c;
-  m_cfg.gpio.d = d; m_cfg.gpio.e = e; 
+  m_cfg.gpio.a = a;
+  m_cfg.gpio.b = b;
+  m_cfg.gpio.c = c;
+  m_cfg.gpio.d = d;
+  m_cfg.gpio.e = e;
 
   // Clock & Control
-  m_cfg.gpio.lat = lat; m_cfg.gpio.oe = oe; m_cfg.gpio.clk = clk;
+  m_cfg.gpio.lat = lat;
+  m_cfg.gpio.oe = oe;
+  m_cfg.gpio.clk = clk;
 
   return begin();
 }
 
-bool MatrixPanel_I2S_DMA::begin(const HUB75_I2S_CFG& cfg){
-  if(initialized) return true;
+bool MatrixPanel_I2S_DMA::begin(const HUB75_I2S_CFG &cfg)
+{
+  if (initialized)
+    return true;
 
-  if(!setCfg(cfg)) return false;
+  if (!setCfg(cfg))
+    return false;
 
   return begin();
 }
 
-
-
 /**
  * @brief - Sets how many clock cycles to blank OE before/after LAT signal change
  * @param uint8_t pulses - clocks before/after OE
@@ -817,7 +737,8 @@ bool MatrixPanel_I2S_DMA::begin(const HUB75_I2S_CFG& cfg){
  * Max is MAX_LAT_BLANKING
  * @returns - new value for m_cfg.latch_blanking
  */
-uint8_t MatrixPanel_I2S_DMA::setLatBlanking(uint8_t pulses){
+uint8_t MatrixPanel_I2S_DMA::setLatBlanking(uint8_t pulses)
+{
   if (pulses > MAX_LAT_BLANKING)
     pulses = MAX_LAT_BLANKING;
 
@@ -831,7 +752,6 @@ uint8_t MatrixPanel_I2S_DMA::setLatBlanking(uint8_t pulses){
   return m_cfg.latch_blanking;
 }
 
-
 #ifndef NO_FAST_FUNCTIONS
 /**
  * @brief - update DMA buff drawing horizontal line at specified coordinates
@@ -840,7 +760,8 @@ uint8_t MatrixPanel_I2S_DMA::setLatBlanking(uint8_t pulses){
  * @param l - line length
  * @param r,g,b, - RGB888 colour
  */
-void MatrixPanel_I2S_DMA::hlineDMA(int16_t x_coord, int16_t y_coord, int16_t l, uint8_t red, uint8_t green, uint8_t blue){
+void MatrixPanel_I2S_DMA::hlineDMA(int16_t x_coord, int16_t y_coord, int16_t l, uint8_t red, uint8_t green, uint8_t blue)
+{
   if (!initialized)
     return;
 
@@ -850,7 +771,6 @@ void MatrixPanel_I2S_DMA::hlineDMA(int16_t x_coord, int16_t y_coord, int16_t l,
   l = x_coord < 0 ? l + x_coord : l;
   x_coord = x_coord < 0 ? 0 : x_coord;
 
-
   l = ((x_coord + l) >= PIXELS_PER_ROW) ? (PIXELS_PER_ROW - x_coord) : l;
 
   // if (x_coord+l > PIXELS_PER_ROW)
@@ -870,7 +790,8 @@ uint16_t red16, green16, blue16;
 
   uint16_t _colourbitclear = BITMASK_RGB1_CLEAR, _colourbitoffset = 0;
 
-  if (y_coord >= ROWS_PER_FRAME){    // if we are drawing to the bottom part of the panel
+  if (y_coord >= ROWS_PER_FRAME)
+  { // if we are drawing to the bottom part of the panel
     _colourbitoffset = BITS_RGB2_OFFSET;
     _colourbitclear = BITMASK_RGB2_CLEAR;
     y_coord -= ROWS_PER_FRAME;
@@ -878,7 +799,8 @@ uint16_t red16, green16, blue16;
 
   // Iterating through colour depth bits (8 iterations)
   uint8_t colour_depth_idx = m_cfg.getPixelColorDepthBits();
-  do {
+  do
+  {
     --colour_depth_idx;
 
     // let's precalculate RGB1 and RGB2 bits than flood it over the entire DMA buffer
@@ -902,12 +824,13 @@ uint16_t red16, green16, blue16;
 
     // Get the contents at this address,
     // it would represent a vector pointing to the full row of pixels for the specified colour depth bit at Y coordinate
-    ESP32_I2S_DMA_STORAGE_TYPE *p = dma_buff.rowBits[y_coord]->getDataPtr(colour_depth_idx, back_buffer_id);
+    ESP32_I2S_DMA_STORAGE_TYPE *p = fb->rowBits[y_coord]->getDataPtr(colour_depth_idx, back_buffer_id);
     // inlined version works slower here, dunno why :(
     // ESP32_I2S_DMA_STORAGE_TYPE *p = getRowDataPtr(y_coord, colour_depth_idx, back_buffer_id);
 
     int16_t _l = l;
-    do {                 // iterate pixels in a row
+    do
+    { // iterate pixels in a row
       int16_t _x = x_coord + --_l;
 
       /*
@@ -927,7 +850,6 @@ uint16_t red16, green16, blue16;
   } while (colour_depth_idx); // end of colour depth loop (8)
 } // hlineDMA()
 
-
 /**
  * @brief - update DMA buff drawing vertical line at specified coordinates
  * @param x_coord - line start coordinate x
@@ -935,7 +857,8 @@ uint16_t red16, green16, blue16;
  * @param l - line length
  * @param r,g,b, - RGB888 colour
  */
-void MatrixPanel_I2S_DMA::vlineDMA(int16_t x_coord, int16_t y_coord, int16_t l, uint8_t red, uint8_t green, uint8_t blue){
+void MatrixPanel_I2S_DMA::vlineDMA(int16_t x_coord, int16_t y_coord, int16_t l, uint8_t red, uint8_t green, uint8_t blue)
+{
   if (!initialized)
     return;
 
@@ -971,7 +894,8 @@ uint16_t red16, green16, blue16;
   x_coord = ESP32_TX_FIFO_POSITION_ADJUST(x_coord);
 
   uint8_t colour_depth_idx = m_cfg.getPixelColorDepthBits();
-  do {    // Iterating through colour depth bits (8 iterations)
+  do
+  { // Iterating through colour depth bits (8 iterations)
     --colour_depth_idx;
 
     // let's precalculate RGB1 and RGB2 bits than flood it over the entire DMA buffer
@@ -995,9 +919,11 @@ uint16_t red16, green16, blue16;
 
     int16_t _l = 0, _y = y_coord;
     uint16_t _colourbitclear = BITMASK_RGB1_CLEAR;
-    do {    // iterate pixels in a column
+    do
+    { // iterate pixels in a column
 
-      if (_y >= ROWS_PER_FRAME){    // if y-coord overlapped bottom-half panel
+      if (_y >= ROWS_PER_FRAME)
+      { // if y-coord overlapped bottom-half panel
         _y -= ROWS_PER_FRAME;
         _colourbitclear = BITMASK_RGB2_CLEAR;
         RGB_output_bits <<= BITS_RGB2_OFFSET;
@@ -1006,7 +932,7 @@ uint16_t red16, green16, blue16;
       // Get the contents at this address,
       // it would represent a vector pointing to the full row of pixels for the specified colour depth bit at Y coordinate
       // ESP32_I2S_DMA_STORAGE_TYPE *p = getRowDataPtr(_y, colour_depth_idx, back_buffer_id);
-      ESP32_I2S_DMA_STORAGE_TYPE *p = dma_buff.rowBits[_y]->getDataPtr(colour_depth_idx, back_buffer_id);      
+      ESP32_I2S_DMA_STORAGE_TYPE *p = fb->rowBits[_y]->getDataPtr(colour_depth_idx, back_buffer_id);
 
       p[x_coord] &= _colourbitclear; // reset RGB bits
       p[x_coord] |= RGB_output_bits; // set new RGB bits
@@ -1015,7 +941,6 @@ uint16_t red16, green16, blue16;
   } while (colour_depth_idx); // end of colour depth loop (8)
 } // vlineDMA()
 
-
 /**
  * @brief - update DMA buff drawing a rectangular at specified coordinates
  * this works much faster than multiple consecutive per-pixel calls to updateMatrixDMABuffer()
@@ -1025,19 +950,25 @@ uint16_t red16, green16, blue16;
  * @param uint8_t g - RGB888 colour
  * @param uint8_t b - RGB888 colour
  */
-void MatrixPanel_I2S_DMA::fillRectDMA(int16_t x, int16_t y, int16_t w, int16_t h, uint8_t r, uint8_t g, uint8_t b){
+void MatrixPanel_I2S_DMA::fillRectDMA(int16_t x, int16_t y, int16_t w, int16_t h, uint8_t r, uint8_t g, uint8_t b)
+{
 
   // h-lines are >2 times faster than v-lines
   // so will use it only for tall rects with h >2w
-  if (h>2*w){
+  if (h > 2 * w)
+  {
     // draw using v-lines
-    do {
+    do
+    {
       --w;
       vlineDMA(x + w, y, h, r, g, b);
     } while (w);
-  } else {
+  }
+  else
+  {
     // draw using h-lines
-    do {
+    do
+    {
       --h;
       hlineDMA(x, y + h, w, r, g, b);
     } while (h);

src/ESP32-HUB75-MatrixPanel-I2S-DMA.h

@@ -52,7 +52,6 @@
 #define CHAIN_LENGTH 1 // Number of modules chained together, i.e. 4 panels chained result in virtualmatrix 64x4=256 px long
 #endif
 
-
 // Interesting Fact: We end up using a uint16_t to send data in parallel to the HUB75... but
 //                   given we only map to 14 physical output wires/bits, we waste 2 bits.
 
@@ -129,54 +128,59 @@
 /** @brief - Structure holds raw DMA data to drive TWO full rows of pixels spanning through all chained modules
  * Note: sizeof(data) must be multiple of 32 bits, as ESP32 DMA linked list buffer address pointer must be word-aligned
  */
-struct rowBitStruct {
+struct rowBitStruct
+{
   const size_t width;
   const uint8_t colour_depth;
   const bool double_buff;
   ESP32_I2S_DMA_STORAGE_TYPE *data;
 
-    /** @brief - returns size of row of data vectorfor a SINGLE buff
-     * size (in bytes) of a vector holding full DMA data for a row of pixels with _dpth colour bits
-     * a SINGLE buffer only size is accounted, when using double buffers it actually takes twice as much space
-     * but returned size is for a half of double-buffer
+  /** @brief 
+   * Returns size (in bytes) of row of data vectorfor a SINGLE buff for the number of colour depths requested
    * 
-     * default - returns full data vector size for a SINGLE buff
+   * default - Returns full data vector size for a SINGLE buff. 
+   *           You should only pass either PIXEL_COLOR_DEPTH_BITS or '1' to this
    *
    */
-    size_t size(uint8_t _dpth=0 ) { if (!_dpth) _dpth = colour_depth; return width * _dpth * sizeof(ESP32_I2S_DMA_STORAGE_TYPE); };
+  size_t getColorDepthSize(uint8_t _dpth = 0)
+  {
+    if (!_dpth)
+      _dpth = colour_depth;
+    return width * _dpth * sizeof(ESP32_I2S_DMA_STORAGE_TYPE);
+  };
 
-    /** @brief - returns pointer to the row's data vector beginning at pixel[0] for _dpth colour bit
-     * default - returns pointer to the data vector's head
+  /** @brief
+   * Returns pointer to the row's data vector beginning at pixel[0] for _dpth colour bit
+   * 
    * NOTE: this call might be very slow in loops. Due to poor instruction caching in esp32 it might be required a reread from flash
    * every loop cycle, better use inlined #define instead in such cases
    */
-    inline ESP32_I2S_DMA_STORAGE_TYPE* getDataPtr(const uint8_t _dpth=0, const bool buff_id=0) { return &(data[_dpth*width + buff_id*(width*colour_depth)]); };
+  // inline ESP32_I2S_DMA_STORAGE_TYPE* getDataPtr(const uint8_t _dpth=0, const bool buff_id=0) { return &(data[_dpth*width + buff_id*(width*colour_depth)]); };
+
+  // BUFFER ID VALUE IS NOW IGNORED!!!!
+  inline ESP32_I2S_DMA_STORAGE_TYPE *getDataPtr(const uint8_t _dpth = 0, const bool buff_id = 0) { return &(data[_dpth * width]); };
 
   // constructor - allocates DMA-capable memory to hold the struct data
-    rowBitStruct(const size_t _width, const uint8_t _depth, const bool _dbuff) : width(_width), colour_depth(_depth), double_buff(_dbuff) {
+  rowBitStruct(const size_t _width, const uint8_t _depth, const bool _dbuff) : width(_width), colour_depth(_depth), double_buff(_dbuff)
+  {
 
     // #if defined(SPIRAM_FRAMEBUFFER) && defined (CONFIG_IDF_TARGET_ESP32S3)
 #if defined(SPIRAM_DMA_BUFFER)
-    //  #pragma message "Enabling PSRAM / SPIRAM for frame buffer."
-    //  ESP_LOGI("rowBitStruct", "Allocated DMA BitBuffer from PSRAM (SPIRAM)");
-      //data = (ESP32_I2S_DMA_STORAGE_TYPE *)heap_caps_malloc( size()+size()*double_buff, MALLOC_CAP_SPIRAM);
-      data = (ESP32_I2S_DMA_STORAGE_TYPE *)heap_caps_aligned_alloc(64, size()+size()*double_buff, MALLOC_CAP_SPIRAM | MALLOC_CAP_8BIT);
-/*
-      if (!psramFound())      
-      {
-        ESP_LOGE("rowBitStruct", "Requested to use PSRAM / SPIRAM for framebuffer, but it was not detected.");
-      }
-*/
-#else
-      data = (ESP32_I2S_DMA_STORAGE_TYPE *)heap_caps_malloc( size()+size()*double_buff, MALLOC_CAP_INTERNAL | MALLOC_CAP_DMA);
-   //   ESP_LOGI("rowBitStruct", "Allocated DMA BitBuffer from regular (and limited) SRAM");      
-#endif
 
+    // data = (ESP32_I2S_DMA_STORAGE_TYPE *)heap_caps_aligned_alloc(64, size()+size()*double_buff, MALLOC_CAP_SPIRAM | MALLOC_CAP_8BIT);
+    // No longer have double buffer in the same struct - have a different struct
+    data = (ESP32_I2S_DMA_STORAGE_TYPE *)heap_caps_aligned_alloc(64, getColorDepthSize(), MALLOC_CAP_SPIRAM | MALLOC_CAP_8BIT);
+#else
+    // data = (ESP32_I2S_DMA_STORAGE_TYPE *)heap_caps_malloc( size()+size()*double_buff, MALLOC_CAP_INTERNAL | MALLOC_CAP_DMA);
+
+    // No longer have double buffer in the same struct - have a different struct
+    data = (ESP32_I2S_DMA_STORAGE_TYPE *)heap_caps_malloc(getColorDepthSize(), MALLOC_CAP_INTERNAL | MALLOC_CAP_DMA);
+
+#endif
   }
   ~rowBitStruct() { delete data; }
 };
 
-
 /* frameStruct
  * Note: A 'frameStruct' contains ALL the data for a full-frame (i.e. BOTH 2x16-row frames are
  *       are contained in parallel within the one uint16_t that is sent in parallel to the HUB75).
@@ -184,7 +188,8 @@ struct rowBitStruct {
  *       This structure isn't actually allocated in one memory block anymore, as the library now allocates
  *       memory per row (per rowBits) instead.
  */
-struct frameStruct {
+struct frameStruct
+{
   uint8_t rows = 0; // number of rows held in current frame, not used actually, just to keep the idea of struct
   std::vector<std::shared_ptr<rowBitStruct>> rowBits;
 };
@@ -216,8 +221,7 @@ static const uint16_t DRAM_ATTR lumConvTab[]={
     31946, 32360, 32777, 33197, 33622, 34049, 34481, 34916, 35354, 35797, 36243, 36692, 37146, 37603, 38064, 38528,
     38996, 39469, 39945, 40424, 40908, 41395, 41886, 42382, 42881, 43383, 43890, 44401, 44916, 45434, 45957, 46484,
     47014, 47549, 48088, 48630, 49177, 49728, 50283, 50842, 51406, 51973, 52545, 53120, 53700, 54284, 54873, 55465,
-    56062, 56663, 57269, 57878, 58492, 59111, 59733, 60360, 60992, 61627, 62268, 62912, 63561, 64215, 64873, 65535
-};
+    56062, 56663, 57269, 57878, 58492, 59111, 59733, 60360, 60992, 61627, 62268, 62912, 63561, 64215, 64873, 65535};
 #endif
 
 /** @brief - configuration values for HUB75_I2S driver
@@ -225,49 +229,65 @@ static const uint16_t DRAM_ATTR lumConvTab[]={
  *  an initialization values when creating an instance of MatrixPanel_I2S_DMA object.
  *  All params have it's default values.
  */
-struct  HUB75_I2S_CFG {
+struct HUB75_I2S_CFG
+{
 
   /**
    * Enumeration of hardware-specific chips
    * used to drive matrix modules
    */
-  enum shift_driver {SHIFTREG=0, FM6124, FM6126A, ICN2038S, MBI5124, SM5266P};
+  enum shift_driver
+  {
+    SHIFTREG = 0,
+    FM6124,
+    FM6126A,
+    ICN2038S,
+    MBI5124,
+    SM5266P,
+    DP3246_SM5368
+  };
 
   /**
    * I2S clock speed selector
    */
-  enum clk_speed {HZ_8M=8000000, HZ_10M=10000000, HZ_15M=15000000, HZ_20M=20000000};
+  enum clk_speed
+  {
+    HZ_8M = 8000000,
+    HZ_10M = 10000000,
+    HZ_15M = 15000000,
+    HZ_20M = 20000000
+  };
 
-  // Structure Variables
+  //
+  // Members must be in order of declaration or it breaks Arduino compiling due to strict checking.
+  //
 
-  /**
-   * GPIO pins mapping
-   */
-  struct i2s_pins{
+  // physical width of a single matrix panel module (in pixels, usually it is 64 ;) )
+  uint16_t mx_width;
+
+  // physical height of a single matrix panel module (in pixels, usually almost always it is either 32 or 64)
+  uint16_t mx_height;
+
+  // number of chained panels regardless of the topology, default 1 - a single matrix module
+  uint16_t chain_length;
+
+  // GPIO Mapping
+  struct i2s_pins
+  {
     int8_t r1, g1, b1, r2, g2, b2, a, b, c, d, e, lat, oe, clk;
   } gpio;
 
   // Matrix driver chip type - default is a plain shift register
   shift_driver driver;
-  // I2S clock speed
-  clk_speed i2sspeed;
-
-  // physical width of a single matrix panel module (in pixels, usually it is 64 ;) )
-  uint16_t mx_width;
-  // physical height of a single matrix panel module (in pixels, usually almost always it is either 32 or 64)
-  uint16_t mx_height;
-  // number of chained panels regardless of the topology, default 1 - a single matrix module
-  uint16_t chain_length;
-
-  // Minimum refresh / scan rate needs to be configured on start due to LSBMSB_TRANSITION_BIT calculation in allocateDMAmemory()
-  uint16_t min_refresh_rate;
-
-  // How many clock cycles to blank OE before/after LAT signal change, default is 1 clock
-  uint8_t latch_blanking;
 
   // use DMA double buffer (twice as much RAM required)
   bool double_buff;
 
+  // I2S clock speed
+  clk_speed i2sspeed;
+
+  // How many clock cycles to blank OE before/after LAT signal change, default is 1 clock
+  uint8_t latch_blanking;
 
   /**
    *  I2S clock phase
@@ -285,6 +305,9 @@ struct  HUB75_I2S_CFG {
    */
   bool clkphase;
 
+  // Minimum refresh / scan rate needs to be configured on start due to LSBMSB_TRANSITION_BIT calculation in allocateDMAmemory()
+  uint8_t min_refresh_rate;
+
   // struct constructor
   HUB75_I2S_CFG(
       uint16_t _w = MATRIX_WIDTH,
@@ -294,44 +317,38 @@ struct  HUB75_I2S_CFG {
           R1_PIN_DEFAULT, G1_PIN_DEFAULT, B1_PIN_DEFAULT, R2_PIN_DEFAULT, G2_PIN_DEFAULT, B2_PIN_DEFAULT,
           A_PIN_DEFAULT, B_PIN_DEFAULT, C_PIN_DEFAULT, D_PIN_DEFAULT, E_PIN_DEFAULT,
           LAT_PIN_DEFAULT, OE_PIN_DEFAULT, CLK_PIN_DEFAULT},
-    shift_driver _drv = SHIFTREG,
-    bool _dbuff = false,
-    clk_speed _i2sspeed = HZ_15M,
+      shift_driver _drv = SHIFTREG, bool _dbuff = false, clk_speed _i2sspeed = HZ_15M,
       uint8_t _latblk = DEFAULT_LAT_BLANKING, // Anything > 1 seems to cause artefacts on ICS panels
-    bool _clockphase = true,
-    uint16_t _min_refresh_rate = 60,
-    uint8_t _pixel_color_depth_bits = PIXEL_COLOR_DEPTH_BITS_DEFAULT
-  ) : mx_width(_w),
-      mx_height(_h),
-      chain_length(_chain),
-      gpio(_pinmap),
-      driver(_drv), 
-	    i2sspeed(_i2sspeed),
-      double_buff(_dbuff),
-      latch_blanking(_latblk),
-      clkphase(_clockphase),
-      min_refresh_rate(_min_refresh_rate)
+      bool _clockphase = true, uint16_t _min_refresh_rate = 60, uint8_t _pixel_color_depth_bits = PIXEL_COLOR_DEPTH_BITS_DEFAULT) : mx_width(_w), mx_height(_h), chain_length(_chain), gpio(_pinmap), driver(_drv), double_buff(_dbuff), i2sspeed(_i2sspeed), latch_blanking(_latblk), clkphase(_clockphase), min_refresh_rate(_min_refresh_rate)
   {
     setPixelColorDepthBits(_pixel_color_depth_bits);
   }
 
   // pixel_color_depth_bits must be between 12 and 2, and mask_offset needs to be calculated accordently
   // so they have to be private with getter (and setter)
-  void setPixelColorDepthBits(uint8_t _pixel_color_depth_bits){
-    if(_pixel_color_depth_bits > PIXEL_COLOR_DEPTH_BITS_MAX || _pixel_color_depth_bits < 2){
+  void setPixelColorDepthBits(uint8_t _pixel_color_depth_bits)
+  {
+    if (_pixel_color_depth_bits > PIXEL_COLOR_DEPTH_BITS_MAX || _pixel_color_depth_bits < 2)
+    {
 
-      if(_pixel_color_depth_bits > PIXEL_COLOR_DEPTH_BITS_MAX){
+      if (_pixel_color_depth_bits > PIXEL_COLOR_DEPTH_BITS_MAX)
+      {
         pixel_color_depth_bits = PIXEL_COLOR_DEPTH_BITS_MAX;
-      }else{
+      }
+      else
+      {
         pixel_color_depth_bits = 2;
       }
       ESP_LOGW("HUB75_I2S_CFG", "Invalid pixel_color_depth_bits (%d): 2 <= pixel_color_depth_bits <= %d, choosing nearest valid %d", _pixel_color_depth_bits, PIXEL_COLOR_DEPTH_BITS_MAX, pixel_color_depth_bits);
-    }else{
+    }
+    else
+    {
       pixel_color_depth_bits = _pixel_color_depth_bits;
     }
   }
 
-  uint8_t getPixelColorDepthBits(){
+  uint8_t getPixelColorDepthBits()
+  {
     return pixel_color_depth_bits;
   }
 
@@ -341,20 +358,20 @@ struct  HUB75_I2S_CFG {
   uint8_t pixel_color_depth_bits;
 }; // end of structure HUB75_I2S_CFG
 
-
-
 /***************************************************************************************/
 #ifdef USE_GFX_ROOT
-class MatrixPanel_I2S_DMA : public GFX {
+class MatrixPanel_I2S_DMA : public GFX
+{
 #elif !defined NO_GFX
-class MatrixPanel_I2S_DMA : public Adafruit_GFX {
+class MatrixPanel_I2S_DMA : public Adafruit_GFX
+{
 #else
-class MatrixPanel_I2S_DMA {
+class MatrixPanel_I2S_DMA
+{
 #endif
 
   // ------- PUBLIC -------
 public:
-
   /**
    * MatrixPanel_I2S_DMA
    *
@@ -367,7 +384,8 @@ class MatrixPanel_I2S_DMA {
 #elif !defined NO_GFX
       : Adafruit_GFX(MATRIX_WIDTH, MATRIX_HEIGHT)
 #endif
-    {}
+  {
+  }
 
   /**
    * MatrixPanel_I2S_DMA
@@ -375,21 +393,24 @@ class MatrixPanel_I2S_DMA {
    * @param  {HUB75_I2S_CFG} opts : structure with matrix configuration
    *
    */
-    MatrixPanel_I2S_DMA(const HUB75_I2S_CFG& opts) :
+  MatrixPanel_I2S_DMA(const HUB75_I2S_CFG &opts)
 #ifdef USE_GFX_ROOT
-      GFX(opts.mx_width*opts.chain_length, opts.mx_height)
+      : GFX(opts.mx_width * opts.chain_length, opts.mx_height)
 #elif !defined NO_GFX
-      Adafruit_GFX(opts.mx_width*opts.chain_length, opts.mx_height)
+      : Adafruit_GFX(opts.mx_width * opts.chain_length, opts.mx_height)
 #endif
   {
     setCfg(opts);
   }
 
   /* Propagate the DMA pin configuration, allocate DMA buffs and start data output, initially blank */
-    bool begin(){
+  bool begin()
+  {
 
-      if (initialized) return true; // we don't do this twice or more!
-      if(!config_set) return false;
+    if (initialized)
+      return true; // we don't do this twice or more!
+    if (!config_set)
+      return false;
 
     ESP_LOGI("begin()", "Using GPIO %d for R1_PIN", m_cfg.gpio.r1);
     ESP_LOGI("begin()", "Using GPIO %d for G1_PIN", m_cfg.gpio.g1);
@@ -406,7 +427,6 @@ class MatrixPanel_I2S_DMA {
     ESP_LOGI("begin()", "Using GPIO %d for OE_PIN", m_cfg.gpio.oe);
     ESP_LOGI("begin()", "Using GPIO %d for CLK_PIN", m_cfg.gpio.clk);
 
-
     // initialize some specific panel drivers
     if (m_cfg.driver)
       shiftDriver(m_cfg);
@@ -420,8 +440,10 @@ class MatrixPanel_I2S_DMA {
     /* As DMA buffers are dynamically allocated, we must allocated in begin()
      * Ref: https://github.com/espressif/arduino-esp32/issues/831
      */
-      if ( !allocateDMAmemory() ) {  return false; } // couldn't even get the basic ram required.
-        
+    if (!allocateDMAmemory())
+    {
+      return false;
+    } // couldn't even get the basic ram required.
 
     // Flush the DMA buffers prior to configuring DMA - Avoid visual artefacts on boot.
     resetbuffers(); // Must fill the DMA buffer with the initial output bit sequence or the panel will display garbage
@@ -431,22 +453,21 @@ class MatrixPanel_I2S_DMA {
 
     // showDMABuffer(); // show backbuf_id of 0
 
-      if (!initialized) {
+    if (!initialized)
+    {
       ESP_LOGE("being()", "MatrixPanel_I2S_DMA::begin() failed!");
     }
 
     return initialized;
-
   }
 
   // Obj destructor
-    ~MatrixPanel_I2S_DMA(){
+  ~MatrixPanel_I2S_DMA()
+  {
 
     dma_bus.release();
-     
   }
 
-
   /*
    *  overload for compatibility
    */
@@ -467,10 +488,10 @@ class MatrixPanel_I2S_DMA {
    * @brief - override Adafruit's FastVLine
    * this works faster than multiple consecutive pixel by pixel drawPixel() call
    */
-    virtual void drawFastVLine(int16_t x, int16_t y, int16_t h, uint16_t color){
+  virtual void drawFastVLine(int16_t x, int16_t y, int16_t h, uint16_t color)
+  {
     uint8_t r, g, b;
     color565to888(color, r, g, b);
-      startWrite();
     
     int16_t w = 1;
     transform(x, y, w, h);
@@ -479,10 +500,10 @@ class MatrixPanel_I2S_DMA {
     else
       hlineDMA(x, y, w, r, g, b);
 
-      endWrite();
   }
   // rgb888 overload
-    virtual inline void drawFastVLine(int16_t x, int16_t y, int16_t h, uint8_t r, uint8_t g, uint8_t b){ 
+  virtual inline void drawFastVLine(int16_t x, int16_t y, int16_t h, uint8_t r, uint8_t g, uint8_t b)
+  {
     int16_t w = 1;
     transform(x, y, w, h);
     if (h > w)
@@ -495,10 +516,10 @@ class MatrixPanel_I2S_DMA {
    * @brief - override Adafruit's FastHLine
    * this works faster than multiple consecutive pixel by pixel drawPixel() call
    */
-    virtual void drawFastHLine(int16_t x, int16_t y, int16_t w, uint16_t color){
+  virtual void drawFastHLine(int16_t x, int16_t y, int16_t w, uint16_t color)
+  {
     uint8_t r, g, b;
     color565to888(color, r, g, b);
-      startWrite();
 
     int16_t h = 1;
     transform(x, y, w, h);
@@ -507,10 +528,10 @@ class MatrixPanel_I2S_DMA {
     else
       hlineDMA(x, y, w, r, g, b);
 
-      endWrite();
   }
   // rgb888 overload
-    virtual inline void drawFastHLine(int16_t x, int16_t y, int16_t w, uint8_t r, uint8_t g, uint8_t b){  
+  virtual inline void drawFastHLine(int16_t x, int16_t y, int16_t w, uint8_t r, uint8_t g, uint8_t b)
+  {
     int16_t h = 1;
     transform(x, y, w, h);
     if (h > w)
@@ -523,20 +544,22 @@ class MatrixPanel_I2S_DMA {
    * @brief - override Adafruit's fillRect
    * this works much faster than multiple consecutive per-pixel drawPixel() calls
    */
-    virtual void fillRect(int16_t x, int16_t y, int16_t w, int16_t h, uint16_t color){
+  virtual void fillRect(int16_t x, int16_t y, int16_t w, int16_t h, uint16_t color)
+  {
     uint8_t r, g, b;
     color565to888(color, r, g, b);
-      startWrite();
+    
     transform(x, y, w, h);
     fillRectDMA(x, y, w, h, r, g, b);
-      endWrite();
+    
   }
   // rgb888 overload
-    virtual inline void fillRect(int16_t x, int16_t y, int16_t w, int16_t h, uint8_t r, uint8_t g, uint8_t b){
-      startWrite();    
+  virtual inline void fillRect(int16_t x, int16_t y, int16_t w, int16_t h, uint8_t r, uint8_t g, uint8_t b)
+  {
+    
     transform(x, y, w, h);
     fillRectDMA(x, y, w, h, r, g, b);
-      endWrite();
+    
   }
 #endif
 
@@ -567,30 +590,19 @@ class MatrixPanel_I2S_DMA {
    */
   static void color565to888(const uint16_t color, uint8_t &r, uint8_t &g, uint8_t &b);
 
-
   inline void flipDMABuffer()
   {
-        if ( !m_cfg.double_buff) { return; }
+    if (!m_cfg.double_buff)
+    {
+      return;
+    }
 	
-        // while (active_gfx_writes) { } // wait a bit ?
-      //  initialized = false;
     dma_bus.flip_dma_output_buffer(back_buffer_id);
-    //    initialized = true;
 	
-        /*
-        i2s_parallel_set_previous_buffer_not_free();       
-        // Wait before we allow any writing to the buffer. Stop flicker.
-        while(i2s_parallel_is_previous_buffer_free() == false) { }       
-        
-        i2s_parallel_flip_to_buffer(ESP32_I2S_DEVICE, back_buffer_id);        
-        // Flip to other buffer as the backbuffer. 
-        // i.e. Graphic changes happen to this buffer, but aren't displayed until flipDMABuffer() is called again.
 	back_buffer_id ^= 1;
+    fb = &frame_buffer[back_buffer_id];	
+	
 
-        i2s_parallel_set_previous_buffer_not_free();       
-        // Wait before we allow any writing to the buffer. Stop flicker.
-        while(i2s_parallel_is_previous_buffer_free() == false) { }          
-        */
 	
   }
 
@@ -608,32 +620,12 @@ class MatrixPanel_I2S_DMA {
     brightness = b;
     brtCtrlOEv2(b, 0);
 
-        if (m_cfg.double_buff) {
+    if (m_cfg.double_buff)
+    {
       brtCtrlOEv2(b, 1);
     }
-		
-		
   }
 
-	// Takes a value that is between 0 and MATRIX_WIDTH-1
-	/*
-    void setPanelBrightness(int b)
-    {
-        if (!initialized)
-		{
-		  ESP_LOGI("setPanelBrightness()", "Tried to set output brightness before begin()");
-          return;
-		}
-		
-      // Change to set the brightness of the display, range of 1 to matrixWidth (i.e. 1 - 64)
-       // brightness = b * PIXELS_PER_ROW / 256;
-
-        brtCtrlOE(b);
-        if (m_cfg.double_buff)
-                brtCtrlOE(b, 1);
-    }
-	*/
-	
   /**
    * @param uint8_t b - 8-bit brightness value
    */
@@ -653,7 +645,6 @@ class MatrixPanel_I2S_DMA {
     // setPanelBrightness(b * PIXELS_PER_ROW / 256);
   }
 
-
   /**
    * @brief - Sets how many clock cycles to blank OE before/after LAT signal change
    * @param uint8_t pulses - clocks before/after OE
@@ -669,8 +660,10 @@ class MatrixPanel_I2S_DMA {
    */
   const HUB75_I2S_CFG &getCfg() const { return m_cfg; };
 
-    inline bool setCfg(const HUB75_I2S_CFG& cfg){
-      if(initialized) return false;
+  inline bool setCfg(const HUB75_I2S_CFG &cfg)
+  {
+    if (initialized)
+      return false;
 
     m_cfg = cfg;
     PIXELS_PER_ROW = m_cfg.mx_width * m_cfg.chain_length;
@@ -684,26 +677,16 @@ class MatrixPanel_I2S_DMA {
   /**
    * Stop the ESP32 DMA Engine. Screen will forever be black until next ESP reboot.
    */
-    void stopDMAoutput() {  
+  void stopDMAoutput()
+  {
     resetbuffers();
     // i2s_parallel_stop_dma(ESP32_I2S_DEVICE);
     dma_bus.dma_transfer_stop();
   }
 
-    void startWrite() {
-      //ESP_LOGI("TAG", "startWrite() called");
-      active_gfx_writes++;
-    }
-    
-
-    void endWrite() {
-      active_gfx_writes--;
-    }    
-
   // ------- PROTECTED -------
   // those might be useful for child classes, like VirtualMatrixPanel
 protected:
-
   /**
    * @brief - clears and reinitializes colour/control data in DMA buffs
    * When allocated, DMA buffs might be dirty, so we need to blank it and initialize ABCDE,LAT,OE control bits.
@@ -712,7 +695,7 @@ class MatrixPanel_I2S_DMA {
    * This effectively clears buffers to blank BLACK and makes it ready to display output.
    * (Brightness control via OE bit manipulation is another case)
    */
-    void clearFrameBuffer(bool _buff_id = 0);
+  void clearFrameBuffer(bool _buff_id);
 
   /* Update a specific pixel in the DMA buffer to a colour */
   void updateMatrixDMABuffer(uint16_t x, uint16_t y, uint8_t red, uint8_t green, uint8_t blue);
@@ -723,18 +706,18 @@ class MatrixPanel_I2S_DMA {
   /**
    * wipes DMA buffer(s) and reset all colour/service bits
    */
-    inline void resetbuffers(){
-		
-      clearFrameBuffer();
+  inline void resetbuffers()
+  {
+    clearFrameBuffer(0);        
     brtCtrlOEv2(brightness, 0); 
 
     if (m_cfg.double_buff) {
+		
       clearFrameBuffer(1);        
       brtCtrlOEv2(brightness, 1);
-      }
 
     }
-
+  }
 
 #ifndef NO_FAST_FUNCTIONS
   /**
@@ -769,7 +752,6 @@ class MatrixPanel_I2S_DMA {
 
   // ------- PRIVATE -------
 private:
-
   /* Calculate the memory available for DMA use, do some other stuff, and allocate accordingly */
   bool allocateDMAmemory();
 
@@ -787,6 +769,11 @@ class MatrixPanel_I2S_DMA {
    */
   void fm6124init(const HUB75_I2S_CFG &_cfg);
 
+  /**
+   * @brief - DP3246-family chips initialization routine
+   */
+  void dp3246init(const HUB75_I2S_CFG& _cfg);
+
   /**
    * @brief - reset OE bits in DMA buffer in a way to control brightness
    * @param brt - brightness level from 0 to row_width
@@ -808,26 +795,46 @@ class MatrixPanel_I2S_DMA {
    * @param w - rectangular width
    * @param h - rectangular height
    */
-    void transform(int16_t &x, int16_t &y, int16_t &w, int16_t &h){
+  void transform(int16_t &x, int16_t &y, int16_t &w, int16_t &h)
+  {
 #ifndef NO_GFX
     int16_t t;
-      switch (rotation) {
-        case 1: t = _height - 1 - y - ( h - 1 ); y = x; x = t; t = h; h = w; w = t; return;
-        case 2: x = _width  - 1 - x - ( w - 1 ); y = _height - 1 - y - ( h - 1 ); return;
-        case 3: t = y; y = _width - 1 - x - ( w - 1 ); x = t; t = h; h = w; w = t; return;
+    switch (rotation)
+    {
+    case 1:
+      t = _height - 1 - y - (h - 1);
+      y = x;
+      x = t;
+      t = h;
+      h = w;
+      w = t;
+      return;
+    case 2:
+      x = _width - 1 - x - (w - 1);
+      y = _height - 1 - y - (h - 1);
+      return;
+    case 3:
+      t = y;
+      y = _width - 1 - x - (w - 1);
+      x = t;
+      t = h;
+      h = w;
+      w = t;
+      return;
     }
 #endif
   };
 
-
 public:
   /**
    * Contains the resulting refresh rate (scan rate) that will be achieved
    * based on the i2sspeed, colour depth and min_refresh_rate requested.
    */
   int calculated_refresh_rate = 0;
+
 protected:
   Bus_Parallel16 dma_bus;
+
 private:
 
   // Matrix i2s settings
@@ -840,15 +847,10 @@ class MatrixPanel_I2S_DMA {
    * Since it's dimensions is unknown prior to class initialization, we just declare it here as empty struct and will do all allocations later.
    * Refer to rowBitStruct to get the idea of it's internal structure
    */
-    frameStruct dma_buff;
+  frameStruct frame_buffer[2];
+  frameStruct *fb; // What framebuffer we are writing pixel changes to? (pointer to either frame_buffer[0] or frame_buffer[1] basically ) used within updateMatrixDMABuffer(...)
 
-    // ESP 32 DMA Linked List descriptor
-    int desccount        = 0;
-    // lldesc_t * dmadesc_a = {0}; 
-    // lldesc_t * dmadesc_b = {0};
-
-    int  active_gfx_writes    = 0;                  // How many async routines are 'drawing' (writing) to the DMA bit buffer. Function called from Adafruit_GFX draw routines like drawCircle etc.
-    int  back_buffer_id       = 0;                       // If using double buffer, which one is NOT active (ie. being displayed) to write too?
+  volatile int back_buffer_id = 0;      // If using double buffer, which one is NOT active (ie. being displayed) to write too?
   int brightness = 128;        // If you get ghosting... reduce brightness level. ((60/64)*255) seems to be the limit before ghosting on a 64 pixel wide physical panel for some panels.
   int lsbMsbTransitionBit = 0; // For colour depth calculations
 
@@ -860,6 +862,7 @@ class MatrixPanel_I2S_DMA {
   uint16_t PIXELS_PER_ROW = m_cfg.mx_width * m_cfg.chain_length;      // number of pixels in a single row of all chained matrix modules (WIDTH of a combined matrix chain)
   uint8_t ROWS_PER_FRAME = m_cfg.mx_height / MATRIX_ROWS_IN_PARALLEL; // RPF - rows per frame, either 16 or 32 depending on matrix module
   uint8_t MASK_OFFSET = 16 - m_cfg.getPixelColorDepthBits();
+
   // Other private variables
   bool initialized = false;
   bool config_set = false;
@@ -875,10 +878,14 @@ class MatrixPanel_I2S_DMA {
  * @param uint16_t colour - RGB565 input colour
  * @param uint8_t &r, &g, &b - refs to variables where converted colours would be emplaced
  */
-inline void MatrixPanel_I2S_DMA::color565to888(const uint16_t color, uint8_t &r, uint8_t &g, uint8_t &b){
-  r = ((((color >> 11) & 0x1F) * 527) + 23) >> 6;
-  g = ((((color >> 5) & 0x3F) * 259) + 33) >> 6;
-  b = (((color & 0x1F) * 527) + 23) >> 6;
+inline void MatrixPanel_I2S_DMA::color565to888(const uint16_t color, uint8_t &r, uint8_t &g, uint8_t &b)
+{
+  r = (color >> 8) & 0xf8;
+  g = (color >> 3) & 0xfc;
+  b = (color << 3);
+  r |= r >> 5;
+  g |= g >> 6;
+  b |= b >> 5;
 }
 
 inline void MatrixPanel_I2S_DMA::drawPixel(int16_t x, int16_t y, uint16_t color) // adafruit virtual void override
@@ -926,19 +933,21 @@ inline void MatrixPanel_I2S_DMA::fillScreen(CRGB color)
 }
 #endif
 
-
 // Pass 8-bit (each) R,G,B, get back 16-bit packed colour
 // https://github.com/squix78/ILI9341Buffer/blob/master/ILI9341_SPI.cpp
-inline uint16_t MatrixPanel_I2S_DMA::color565(uint8_t r, uint8_t g, uint8_t b) {
+inline uint16_t MatrixPanel_I2S_DMA::color565(uint8_t r, uint8_t g, uint8_t b)
+{
   return ((r & 0xF8) << 8) | ((g & 0xFC) << 3) | (b >> 3);
 }
 
 // Promote 3/3/3 RGB to Adafruit_GFX 5/6/5 RRRrrGGGgggBBBbb
-inline uint16_t MatrixPanel_I2S_DMA::color333(uint8_t r, uint8_t g, uint8_t b) { 
+inline uint16_t MatrixPanel_I2S_DMA::color333(uint8_t r, uint8_t g, uint8_t b)
+{
   return ((r & 0x7) << 13) | ((r & 0x6) << 10) | ((g & 0x7) << 8) | ((g & 0x7) << 5) | ((b & 0x7) << 2) | ((b & 0x6) >> 1);
 }
 
-inline void MatrixPanel_I2S_DMA::drawIcon (int *ico, int16_t x, int16_t y, int16_t cols, int16_t rows) {
+inline void MatrixPanel_I2S_DMA::drawIcon(int *ico, int16_t x, int16_t y, int16_t cols, int16_t rows)
+{
   /*  drawIcon draws a C style bitmap.
   //  Example 10x5px bitmap of a yellow sun
   //
@@ -956,18 +965,17 @@ inline void MatrixPanel_I2S_DMA::drawIcon (int *ico, int16_t x, int16_t y, int16
   */
 
   int i, j;
-  for (i = 0; i < rows; i++) {
-    for (j = 0; j < cols; j++) {
+  for (i = 0; i < rows; i++)
+  {
+    for (j = 0; j < cols; j++)
+    {
       drawPixel(x + j, y + i, (uint16_t)ico[i * cols + j]);
     }
   }
 }
 
-
 #endif
 
-
-
 // Credits: Louis Beaudoin <https://github.com/pixelmatix/SmartMatrix/tree/teensylc>
 // and Sprite_TM:           https://www.esp32.com/viewtopic.php?f=17&t=3188 and https://www.esp32.com/viewtopic.php?f=13&t=3256
 

src/ESP32-HUB75-MatrixPanel-leddrivers.cpp

@@ -27,6 +27,9 @@ void MatrixPanel_I2S_DMA::shiftDriver(const HUB75_I2S_CFG& _cfg){
     case HUB75_I2S_CFG::FM6126A:
         fm6124init(_cfg);
         break;
+    case HUB75_I2S_CFG::DP3246_SM5368:
+        dp3246init(_cfg);
+        break;
     case HUB75_I2S_CFG::MBI5124:
         /* MBI5124 chips must be clocked with positive-edge, since it's LAT signal
         * resets on clock's rising edge while high
@@ -49,6 +52,7 @@ void MatrixPanel_I2S_DMA::fm6124init(const HUB75_I2S_CFG& _cfg) {
     bool REG2[16] = {0,0,0,0,0, 0,0,0,0,1,0, 0,0,0,0,0};    // a single bit enables the matrix output
 
     for (uint8_t _pin:{_cfg.gpio.r1, _cfg.gpio.r2, _cfg.gpio.g1, _cfg.gpio.g2, _cfg.gpio.b1, _cfg.gpio.b2, _cfg.gpio.clk, _cfg.gpio.lat, _cfg.gpio.oe}){
+        gpio_reset_pin((gpio_num_t)_pin);                        // some pins are not in gpio mode after reset => https://docs.espressif.com/projects/esp-idf/en/latest/esp32/api-reference/peripherals/gpio.html#gpio-summary
         gpio_set_direction((gpio_num_t) _pin, GPIO_MODE_OUTPUT);
         gpio_set_level((gpio_num_t) _pin, LOW);
     }
@@ -98,3 +102,89 @@ void MatrixPanel_I2S_DMA::fm6124init(const HUB75_I2S_CFG& _cfg) {
     gpio_set_level((gpio_num_t) _cfg.gpio.oe, LOW); // Enable Display
     CLK_PULSE
 }
+
+void MatrixPanel_I2S_DMA::dp3246init(const HUB75_I2S_CFG& _cfg) {
+
+    ESP_LOGI("LEDdrivers", "MatrixPanel_I2S_DMA - initializing DP3246 driver...");
+
+    // DP3246 needs positive clock edge
+    m_cfg.clkphase = true;
+
+    // 15:13   3   000        reserved
+    // 12:9    4   0000       OE widening (= OE_ADD * 6ns)
+    // 8       1   0          reserved
+    // 7:0     8   11111111   Iout = (Igain+1)/256 * 17.6 / Rext
+    bool REG1[16] = { 0,0,0, 0,0,0,0, 0, 1,1,1,1,1,1,1,1 };  // MSB first
+
+    // 15:11   5   11111      Blanking potential selection, step 77mV, 00000: VDD-0.8V
+    // 10:8    3   111        Constant current source output inflection point selection
+    // 7       1   0          Disable dead pixel removel, 1: Enable
+    // 6       1   0          0->1: (OPEN_DET rising edge) start detection, 0: reset to ready-to-detect state
+    // 5       1   0          0: Enable black screen power saving, 1: Turn off the black screen to save energy
+    // 4       1   0          0: Do not enable the fading function, 1: Enable the fade function
+    // 3       1   0          Reserved
+    // 2:0     3   000        000: single edge pass, others: double edge transfer
+    bool REG2[16] = { 1,1,1,1,1, 1,1,1, 0, 0, 0, 0, 0, 0,0,0 };  // MSB first
+
+    for (uint8_t _pin : {_cfg.gpio.r1, _cfg.gpio.r2, _cfg.gpio.g1, _cfg.gpio.g2, _cfg.gpio.b1, _cfg.gpio.b2, _cfg.gpio.clk, _cfg.gpio.lat, _cfg.gpio.oe}) {
+        gpio_reset_pin((gpio_num_t)_pin);                        // some pins are not in gpio mode after reset => https://docs.espressif.com/projects/esp-idf/en/latest/esp32/api-reference/peripherals/gpio.html#gpio-summary
+        gpio_set_direction((gpio_num_t)_pin, GPIO_MODE_OUTPUT);
+        gpio_set_level((gpio_num_t)_pin, LOW);
+    }
+
+    gpio_set_level((gpio_num_t)_cfg.gpio.oe, HIGH); // disable Display
+
+    // clear registers - this seems to help with reliability
+    for (int l = 0; l < PIXELS_PER_ROW; ++l) {
+        if (l == PIXELS_PER_ROW - 3) {       // DP3246 wants the latch dropped for 3 clk cycles
+            gpio_set_level((gpio_num_t)_cfg.gpio.lat, HIGH);
+        }
+        CLK_PULSE
+    }
+
+    gpio_set_level((gpio_num_t)_cfg.gpio.lat, LOW);
+
+    // Send Data to control register REG1
+    for (int l = 0; l < PIXELS_PER_ROW; l++) {
+        for (uint8_t _pin : {_cfg.gpio.r1, _cfg.gpio.r2, _cfg.gpio.g1, _cfg.gpio.g2, _cfg.gpio.b1, _cfg.gpio.b2})
+            gpio_set_level((gpio_num_t)_pin, REG1[l % 16]);   // we have 16 bits shifters and write the same value all over the matrix array
+
+        if (l == PIXELS_PER_ROW - 11) {         // pull the latch 11 clocks before the end of matrix so that REG1 starts counting to save the value
+            gpio_set_level((gpio_num_t)_cfg.gpio.lat, HIGH);
+        }
+        CLK_PULSE
+    }
+
+    // drop the latch and save data to the REG1 all over the DP3246 chips
+    gpio_set_level((gpio_num_t)_cfg.gpio.lat, LOW);
+
+    // Send Data to control register REG2
+    for (int l = 0; l < PIXELS_PER_ROW; l++) {
+        for (uint8_t _pin : {_cfg.gpio.r1, _cfg.gpio.r2, _cfg.gpio.g1, _cfg.gpio.g2, _cfg.gpio.b1, _cfg.gpio.b2})
+            gpio_set_level((gpio_num_t)_pin, REG2[l % 16]);   // we have 16 bits shifters and we write the same value all over the matrix array
+
+        if (l == PIXELS_PER_ROW - 12) {       // pull the latch 12 clocks before the end of matrix so that REG2 starts counting to save the value
+            gpio_set_level((gpio_num_t)_cfg.gpio.lat, HIGH);
+        }
+        CLK_PULSE
+    }
+
+    // drop the latch and save data to the REG2 all over the DP3246 chips
+    gpio_set_level((gpio_num_t)_cfg.gpio.lat, LOW);
+    CLK_PULSE
+
+    // blank data regs to keep matrix clear after manipulations
+    for (uint8_t _pin : {_cfg.gpio.r1, _cfg.gpio.r2, _cfg.gpio.g1, _cfg.gpio.g2, _cfg.gpio.b1, _cfg.gpio.b2})
+        gpio_set_level((gpio_num_t)_pin, LOW);
+
+    for (int l = 0; l < PIXELS_PER_ROW; ++l) {
+        if (l == PIXELS_PER_ROW - 3) {       // DP3246 wants the latch dropped for 3 clk cycles
+            gpio_set_level((gpio_num_t)_cfg.gpio.lat, HIGH);
+        }
+        CLK_PULSE
+    }
+
+    gpio_set_level((gpio_num_t)_cfg.gpio.lat, LOW);
+    gpio_set_level((gpio_num_t)_cfg.gpio.oe, LOW); // enable Display
+    CLK_PULSE
+}

src/ESP32-VirtualMatrixPanel-I2S-DMA.h

@@ -30,6 +30,8 @@
 #include <Fonts/FreeSansBold12pt7b.h>
 #endif
 
+// #include <iostream>
+
 struct VirtualCoords
 {
     int16_t x;
@@ -44,9 +46,25 @@ struct VirtualCoords
 
 enum PANEL_SCAN_RATE
 {
-  NORMAL_TWO_SCAN, NORMAL_ONE_SIXTEEN, // treated as the same
+    NORMAL_TWO_SCAN,
+    NORMAL_ONE_SIXTEEN, // treated as the same
     FOUR_SCAN_32PX_HIGH,
-  FOUR_SCAN_16PX_HIGH
+    FOUR_SCAN_16PX_HIGH,
+    FOUR_SCAN_64PX_HIGH
+};
+
+// Chaining approach... From the perspective of the DISPLAY / LED side of the chain of panels.
+enum PANEL_CHAIN_TYPE
+{
+    CHAIN_NONE,
+    CHAIN_TOP_LEFT_DOWN,
+    CHAIN_TOP_RIGHT_DOWN,
+    CHAIN_BOTTOM_LEFT_UP,
+    CHAIN_BOTTOM_RIGHT_UP,
+    CHAIN_TOP_LEFT_DOWN_ZZ, /// ZigZag chaining. Might need a big ass cable to do this, all panels right way up.
+    CHAIN_TOP_RIGHT_DOWN_ZZ,
+    CHAIN_BOTTOM_RIGHT_UP_ZZ,
+    CHAIN_BOTTOM_LEFT_UP_ZZ
 };
 
 #ifdef USE_GFX_ROOT
@@ -59,20 +77,7 @@ class VirtualMatrixPanel
 {
 
 public:
-  int16_t virtualResX;
-  int16_t virtualResY;
-
-  int16_t vmodule_rows;
-  int16_t vmodule_cols;
-
-  int16_t panelResX;
-  int16_t panelResY;
-
-  int16_t dmaResX; // The width of the chain in pixels (as the DMA engine sees it)
-
-  MatrixPanel_I2S_DMA *display;
-
-  VirtualMatrixPanel(MatrixPanel_I2S_DMA &disp, int _vmodule_rows, int _vmodule_cols, int _panelResX, int _panelResY, bool serpentine_chain = true, bool top_down_chain = false)
+    VirtualMatrixPanel(MatrixPanel_I2S_DMA &disp, int _vmodule_rows, int _vmodule_cols, int _panelResX, int _panelResY, PANEL_CHAIN_TYPE _panel_chain_type = CHAIN_NONE)
 #ifdef USE_GFX_ROOT
         : GFX(_vmodule_cols * _panelResX, _vmodule_rows * _panelResY)
 #elif !defined NO_GFX
@@ -81,6 +86,8 @@ public:
     {
         this->display = &disp;
 
+        panel_chain_type = _panel_chain_type;
+
         panelResX = _panelResX;
         panelResY = _panelResY;
 
@@ -90,7 +97,7 @@ public:
         virtualResX = vmodule_cols * _panelResX;
         virtualResY = vmodule_rows * _panelResY;
 
-    dmaResX = panelResX * vmodule_rows * vmodule_cols;
+        dmaResX = panelResX * vmodule_rows * vmodule_cols - 1;
 
         /* Virtual Display width() and height() will return a real-world value. For example:
          * Virtual Display width: 128
@@ -99,17 +106,15 @@ public:
          * So, not values that at 0 to X-1
          */
 
-    _s_chain_party = serpentine_chain; // serpentine, or 'S' chain?
-    _chain_top_down = top_down_chain;
-
         coords.x = coords.y = -1; // By default use an invalid co-ordinates that will be rejected by updateMatrixDMABuffer
     }
 
     // equivalent methods of the matrix library so it can be just swapped out.
-  virtual void drawPixel(int16_t x, int16_t y, uint16_t color);
-  virtual void fillScreen(uint16_t color); // overwrite adafruit implementation
-  virtual void fillScreenRGB888(uint8_t r, uint8_t g, uint8_t b);
+    void drawPixel(int16_t x, int16_t y, uint16_t color);   // overwrite adafruit implementation
+    void fillScreen(uint16_t color); 			// overwrite adafruit implementation
+    void setRotation(int rotate); 				// overwrite adafruit implementation
     
+	void fillScreenRGB888(uint8_t r, uint8_t g, uint8_t b);
     void clearScreen() { display->clearScreen(); }
     void drawPixelRGB888(int16_t x, int16_t y, uint8_t r, uint8_t g, uint8_t b);
 
@@ -119,25 +124,45 @@ public:
     void drawPixel(int16_t x, int16_t y, CRGB color);
 #endif
 
-  uint16_t color444(uint8_t r, uint8_t g, uint8_t b) { return display->color444(r, g, b); }
+    uint16_t color444(uint8_t r, uint8_t g, uint8_t b)
+    {
+        return display->color444(r, g, b);
+    }
     uint16_t color565(uint8_t r, uint8_t g, uint8_t b) { return display->color565(r, g, b); }
     uint16_t color333(uint8_t r, uint8_t g, uint8_t b) { return display->color333(r, g, b); }
 
     void flipDMABuffer() { display->flipDMABuffer(); }
     void drawDisplayTest();
-  void setRotate(bool rotate);
 
     void setPhysicalPanelScanRate(PANEL_SCAN_RATE rate);
+	void setZoomFactor(int scale);
 
-protected:
-  virtual VirtualCoords getCoords(int16_t &x, int16_t &y);
+private:
+    MatrixPanel_I2S_DMA *display;
+
+    PANEL_CHAIN_TYPE panel_chain_type;
+    PANEL_SCAN_RATE panel_scan_rate = NORMAL_TWO_SCAN;
+
+    virtual VirtualCoords getCoords(int16_t x, int16_t y);
     VirtualCoords coords;
 
-  bool _s_chain_party = true;   // Are we chained? Ain't no party like a...
-  bool _chain_top_down = false; // is the ESP at the top or bottom of the matrix of devices?
-  bool _rotate = false;
+    int16_t virtualResX;
+    int16_t virtualResY;
 	
-  PANEL_SCAN_RATE _panelScanRate = NORMAL_TWO_SCAN;
+	int16_t _virtualResX;       ///< Display width as modified by current rotation
+	int16_t _virtualResY;       ///< Display height as modified by current rotation	
+
+    int16_t vmodule_rows;
+    int16_t vmodule_cols;
+
+    int16_t panelResX;
+    int16_t panelResY;
+
+    int16_t dmaResX; // The width of the chain in pixels (as the DMA engine sees it)
+
+    int _rotate = 0;
+	
+	int _scale_factor = 0;
 
 }; // end Class header
 
@@ -146,72 +171,207 @@ protected:
  * Updates the private class member variable 'coords', so no need to use the return value.
  * Not thread safe, but not a concern for ESP32 sketch anyway... I think.
  */
-inline VirtualCoords VirtualMatrixPanel::getCoords(int16_t &x, int16_t &y)
+inline VirtualCoords VirtualMatrixPanel::getCoords(int16_t virt_x, int16_t virt_y)
 {
-  // Serial.println("Called Base.");
-  coords.x = coords.y = -1; // By defalt use an invalid co-ordinates that will be rejected by updateMatrixDMABuffer
 	
-  // Do we want to rotate?
-  if (_rotate)
-  {
-    int16_t temp_x = x;
-    x = y;
-    y = virtualResY - 1 - temp_x;
-  }
+#if !defined NO_GFX
+	// I don't give any support if Adafruit GFX isn't being used.
 	
-  if (x < 0 || x >= virtualResX || y < 0 || y >= virtualResY)
+    if (virt_x < 0 || virt_x >= _width || virt_y < 0 || virt_y >= _height) // _width and _height are defined in the adafruit constructor
     {                             // Co-ordinates go from 0 to X-1 remember! otherwise they are out of range!
-    // Serial.printf("VirtualMatrixPanel::getCoords(): Invalid virtual display coordinate. x,y: %d, %d\r\n", x, y);
+        coords.x = coords.y = -1; // By defalt use an invalid co-ordinates that will be rejected by updateMatrixDMABuffer
+        return coords;
+    }
+#else
+	
+    if (virt_x < 0 || virt_x >= _virtualResX || virt_y < 0 || virt_y >= _virtualResY) // _width and _height are defined in the adafruit constructor
+    {                             // Co-ordinates go from 0 to X-1 remember! otherwise they are out of range!
+        coords.x = coords.y = -1; // By defalt use an invalid co-ordinates that will be rejected by updateMatrixDMABuffer
         return coords;
     }
 	
-  // Stupidity check
-  if ((vmodule_rows == 1) && (vmodule_cols == 1)) // single panel...
-  {
-    coords.x = x;
-    coords.y = y;
-  }
-  else
-  {
-    uint8_t row = (y / panelResY) + 1;                         // a non indexed 0 row number
-    if ((_s_chain_party && !_chain_top_down && (row % 2 == 0)) // serpentine vertically stacked chain starting from bottom row (i.e. ESP closest to ground), upwards
-        ||
-        (_s_chain_party && _chain_top_down && (row % 2 != 0)) // serpentine vertically stacked chain starting from the sky downwards
-    )
-    {
-      // First portion gets you to the correct offset for the row you need
-      // Second portion inverts the x on the row
-      coords.x = ((y / panelResY) * (virtualResX)) + (virtualResX - x) - 1;
+#endif
     
-      // inverts the y the row
-      coords.y = panelResY - 1 - (y % panelResY);
-    }
-    else
+    // Do we want to rotate?
+    switch (_rotate) {
+      case 0: //no rotation, do nothing
+      break;
+      
+      case (1): //90 degree rotation
       {
-      // Normal chain pixel co-ordinate
-      coords.x = x + ((y / panelResY) * (virtualResX));
-      coords.y = y % panelResY;
+        int16_t temp_x = virt_x;
+        virt_x = virt_y;
+        virt_y = virtualResY - 1 - temp_x;
+        break;
+      }
+
+      case (2): //180 rotation
+      {
+        virt_x = virtualResX - 1 - virt_x;
+        virt_y = virtualResY - 1 - virt_y;
+        break;
+      }
+
+      case (3): //270 rotation
+      {
+        int16_t temp_x = virt_x;
+        virt_x = virtualResX - 1 - virt_y;
+        virt_y = temp_x;
+        break;
       }
     }
 
-  // Reverse co-ordinates if panel chain from ESP starts from the TOP RIGHT
-  if (_chain_top_down)
+    int row = (virt_y / panelResY); // 0 indexed
+    switch (panel_chain_type)
     {
-    /*
-    const HUB75_I2S_CFG _cfg = this->display->getCfg();
-    coords.x = (_cfg.mx_width * _cfg.chain_length - 1) - coords.x;
-    coords.y = (_cfg.mx_height-1) - coords.y;
-    */
-    coords.x = (dmaResX - 1) - coords.x;
-    coords.y = (panelResY - 1) - coords.y;
+        case (CHAIN_TOP_RIGHT_DOWN):
+        {
+            if ((row % 2) == 1)
+            { // upside down panel
+
+                // Serial.printf("Condition 1, row %d ", row);
+
+                // reversed for the row
+                coords.x = dmaResX - virt_x - (row * virtualResX);
+
+                // y co-ord inverted within the panel
+                coords.y = panelResY - 1 - (virt_y % panelResY);
             }
+            else
+            {
+                // Serial.printf("Condition 2, row %d ", row);
+                coords.x = ((vmodule_rows - (row + 1)) * virtualResX) + virt_x;
+                coords.y = (virt_y % panelResY);
+            }
+        }
+        break;
+
+        case (CHAIN_TOP_RIGHT_DOWN_ZZ):
+        {
+            //	Right side up. Starting from top right all the way down.
+            //  Connected in a Zig Zag manner = some long ass cables being used potentially
+
+            // Serial.printf("Condition 2, row %d ", row);
+            coords.x = ((vmodule_rows - (row + 1)) * virtualResX) + virt_x;
+            coords.y = (virt_y % panelResY);
+        }
+        break;
+
+        case (CHAIN_TOP_LEFT_DOWN): // OK -> modulus opposite of CHAIN_TOP_RIGHT_DOWN
+        {
+            if ((row % 2) == 0)
+            { // reversed panel
+
+                // Serial.printf("Condition 1, row %d ", row);
+                coords.x = dmaResX - virt_x - (row * virtualResX);
+
+                // y co-ord inverted within the panel
+                coords.y = panelResY - 1 - (virt_y % panelResY);
+            }
+            else
+            {
+                // Serial.printf("Condition 2, row %d ", row);
+                coords.x = ((vmodule_rows - (row + 1)) * virtualResX) + virt_x;
+                coords.y = (virt_y % panelResY);
+            }
+        }
+        break;
+
+        case (CHAIN_TOP_LEFT_DOWN_ZZ):
+        {
+            // Serial.printf("Condition 2, row %d ", row);
+            coords.x = ((vmodule_rows - (row + 1)) * virtualResX) + virt_x;
+            coords.y = (virt_y % panelResY);
+        }
+        break;
+
+        case (CHAIN_BOTTOM_LEFT_UP): //
+        {
+            row = vmodule_rows - row - 1;
+
+            if ((row % 2) == 1)
+            {
+                // Serial.printf("Condition 1, row %d ", row);
+                coords.x = ((vmodule_rows - (row + 1)) * virtualResX) + virt_x;
+                coords.y = (virt_y % panelResY);
+            }
+            else
+            { // inverted panel
+
+                // Serial.printf("Condition 2, row %d ", row);
+                coords.x = dmaResX - (row * virtualResX) - virt_x;
+                coords.y = panelResY - 1 - (virt_y % panelResY);
+            }
+        }
+        break;
+
+        case (CHAIN_BOTTOM_LEFT_UP_ZZ): //
+        {
+            row = vmodule_rows - row - 1;
+            // Serial.printf("Condition 1, row %d ", row);
+            coords.x = ((vmodule_rows - (row + 1)) * virtualResX) + virt_x;
+            coords.y = (virt_y % panelResY);
+        }
+        break;
+
+        case (CHAIN_BOTTOM_RIGHT_UP): // OK -> modulus opposite of CHAIN_BOTTOM_LEFT_UP
+        {
+            row = vmodule_rows - row - 1;
+
+            if ((row % 2) == 0)
+            { // right side up
+
+                // Serial.printf("Condition 1, row %d ", row);
+                // refersed for the row
+                coords.x = ((vmodule_rows - (row + 1)) * virtualResX) + virt_x;
+                coords.y = (virt_y % panelResY);
+            }
+            else
+            { // inverted panel
+
+                // Serial.printf("Condition 2, row %d ", row);
+                coords.x = dmaResX - (row * virtualResX) - virt_x;
+                coords.y = panelResY - 1 - (virt_y % panelResY);
+            }
+        }
+        break;
+
+        case (CHAIN_BOTTOM_RIGHT_UP_ZZ):
+        {
+            //	Right side up. Starting bottom right all the way up.
+            //  Connected in a Zig Zag manner = some long ass cables being used potentially
+
+            row = vmodule_rows - row - 1;
+            // Serial.printf("Condition 2, row %d ", row);
+            coords.x = ((vmodule_rows - (row + 1)) * virtualResX) + virt_x;
+            coords.y = (virt_y % panelResY);
+        }
+        break;
+
+	    // Q: 1 row!? Why?
+        // A: In cases people are only using virtual matrix panel for panels of non-standard scan rates.
+        default: 
+            coords.x = virt_x; coords.y = virt_y; 
+            break;
+            
+    } // end switch
+	
 
     /* START: Pixel remapping AGAIN to convert TWO parallel scanline output that the
      *        the underlying hardware library is designed for (because
      *        there's only 2 x RGB pins... and convert this to 1/4 or something
      */	
-  if (_panelScanRate == FOUR_SCAN_32PX_HIGH)
+	
+    if ((panel_scan_rate == FOUR_SCAN_32PX_HIGH) || (panel_scan_rate == FOUR_SCAN_64PX_HIGH))
     {
+
+	if (panel_scan_rate == FOUR_SCAN_64PX_HIGH)
+	{
+	    // https://github.com/mrfaptastic/ESP32-HUB75-MatrixPanel-DMA/issues/345#issuecomment-1510401192
+	    if ((virt_y & 8) != ((virt_y & 16) >> 1)) { virt_y = (virt_y & 0b11000) ^ 0b11000 + (virt_y & 0b11100111); }
+	}
+
+
         /* Convert Real World 'VirtualMatrixPanel' co-ordinates (i.e. Real World pixel you're looking at
            on the panel or chain of panels, per the chaining configuration) to a 1/8 panels
            double 'stretched' and 'squished' coordinates which is what needs to be sent from the
@@ -221,12 +381,7 @@ inline VirtualCoords VirtualMatrixPanel::getCoords(int16_t &x, int16_t &y)
            as if the panel is 2 * W and 0.5 * H !
         */
 
-    /*
-      Serial.print("VirtualMatrixPanel Mapping ("); Serial.print(x, DEC); Serial.print(","); Serial.print(y, DEC); Serial.print(") ");
-      // to
-      Serial.print("to ("); Serial.print(coords.x, DEC);  Serial.print(",");  Serial.print(coords.y, DEC);   Serial.println(") ");
-     */
-    if ((y & 8) == 0)
+        if ((virt_y & 8) == 0)
         {
             coords.x += ((coords.x / panelResX) + 1) * panelResX; // 1st, 3rd 'block' of 8 rows of pixels, offset by panel width in DMA buffer
         }
@@ -238,17 +393,11 @@ inline VirtualCoords VirtualMatrixPanel::getCoords(int16_t &x, int16_t &y)
         // http://cpp.sh/4ak5u
         // Real number of DMA y rows is half reality
         // coords.y = (y / 16)*8 + (y & 0b00000111);
-    coords.y = (y >> 4) * 8 + (y & 0b00000111);
-
-    /*
-     Serial.print("OneEightScanPanel Mapping ("); Serial.print(x, DEC); Serial.print(","); Serial.print(y, DEC); Serial.print(") ");
-     // to
-     Serial.print("to ("); Serial.print(coords.x, DEC);  Serial.print(",");  Serial.print(coords.y, DEC);   Serial.println(") ");
-    */
+        coords.y = (virt_y >> 4) * 8 + (virt_y & 0b00000111);
     }
-  else if (_panelScanRate == FOUR_SCAN_16PX_HIGH)
+    else if (panel_scan_rate == FOUR_SCAN_16PX_HIGH)
     {
-    if ((y & 8) == 0)
+        if ((virt_y & 8) == 0)
         {
             coords.x += (panelResX >> 2) * (((coords.x & 0xFFF0) >> 4) + 1); // 1st, 3rd 'block' of 8 rows of pixels, offset by panel width in DMA buffer
         }
@@ -257,24 +406,41 @@ inline VirtualCoords VirtualMatrixPanel::getCoords(int16_t &x, int16_t &y)
             coords.x += (panelResX >> 2) * (((coords.x & 0xFFF0) >> 4)); // 2nd, 4th 'block' of 8 rows of pixels, offset by panel width in DMA buffer
         }
 
-    if (y < 32)
-      coords.y = (y >> 4) * 8 + (y & 0b00000111);
+        if (virt_y < 32)
+            coords.y = (virt_y >> 4) * 8 + (virt_y & 0b00000111);
         else
         {
-      coords.y = ((y - 32) >> 4) * 8 + (y & 0b00000111);
+            coords.y = ((virt_y - 32) >> 4) * 8 + (virt_y & 0b00000111);
             coords.x += 256;
         }
     }
 
-  // Serial.print("Mapping to x: "); Serial.print(coords.x, DEC);  Serial.print(", y: "); Serial.println(coords.y, DEC);
     return coords;
 }
 
 inline void VirtualMatrixPanel::drawPixel(int16_t x, int16_t y, uint16_t color)
 { // adafruit virtual void override
-  getCoords(x, y);
+
+	if (_scale_factor > 1) // only from 2 and beyond
+	{
+		int16_t scaled_x_start_pos = x * _scale_factor;
+		int16_t scaled_y_start_pos = y * _scale_factor;
+		
+		for (int16_t x = 0; x < _scale_factor; x++) {
+			for (int16_t y = 0; y < _scale_factor; y++) {	
+				VirtualCoords result = this->getCoords(scaled_x_start_pos+x, scaled_y_start_pos+y);
+				// Serial.printf("Requested virtual x,y coord (%d, %d), got phyical chain coord of (%d,%d)\n", x,y, coords.x, coords.y);
+				this->display->drawPixel(result.x, result.y, color);
+			}
+		}
+	}
+	else
+	{
+		this->getCoords(x, y);
+		// Serial.printf("Requested virtual x,y coord (%d, %d), got phyical chain coord of (%d,%d)\n", x,y, coords.x, coords.y);
 		this->display->drawPixel(coords.x, coords.y, color);	
 	}
+}
 
 inline void VirtualMatrixPanel::fillScreen(uint16_t color)
 { // adafruit virtual void override
@@ -288,7 +454,7 @@ inline void VirtualMatrixPanel::fillScreenRGB888(uint8_t r, uint8_t g, uint8_t b
 
 inline void VirtualMatrixPanel::drawPixelRGB888(int16_t x, int16_t y, uint8_t r, uint8_t g, uint8_t b)
 {
-  getCoords(x, y);
+    this->getCoords(x, y);
     this->display->drawPixelRGB888(coords.x, coords.y, r, g, b);
 }
 
@@ -296,7 +462,7 @@ inline void VirtualMatrixPanel::drawPixelRGB888(int16_t x, int16_t y, uint8_t r,
 // Support for CRGB values provided via FastLED
 inline void VirtualMatrixPanel::drawPixel(int16_t x, int16_t y, CRGB color)
 {
-  getCoords(x, y);
+    this->getCoords(x, y);
     this->display->drawPixel(coords.x, coords.y, color);
 }
 
@@ -306,31 +472,56 @@ inline void VirtualMatrixPanel::fillScreen(CRGB color)
 }
 #endif
 
-inline void VirtualMatrixPanel::setRotate(bool rotate)
+inline void VirtualMatrixPanel::setRotation(int rotate)
 {
+  if(rotate < 4 && rotate >= 0)
     _rotate = rotate;
 
-#ifndef NO_GFX
-  // We don't support rotation by degrees.
-  if (rotate)
-  {
-    setRotation(1);
-  }
-  else
-  {
-    setRotation(0);
-  }
+  // Change the _width and _height variables used by the underlying adafruit gfx library.
+  // Actual pixel rotation / mapping is done in the getCoords function.
+  rotation = (rotate & 3);
+  switch (rotation) {
+  case 0: // nothing
+  case 2: // 180
+	_virtualResX = virtualResX;
+	_virtualResY = virtualResY;
+
+#if !defined NO_GFX	
+    _width = virtualResX; // adafruit base class 
+    _height = virtualResY; // adafruit base class 
 #endif 
+    break;
+  case 1:
+  case 3:
+	_virtualResX = virtualResY;
+	_virtualResY = virtualResX;
+	
+#if !defined NO_GFX		
+    _width = virtualResY; // adafruit base class 
+    _height = virtualResX; // adafruit base class 
+#endif 	
+    break;
+  }
+
+  
 }
 
 inline void VirtualMatrixPanel::setPhysicalPanelScanRate(PANEL_SCAN_RATE rate)
 {
-  _panelScanRate = rate;
+    panel_scan_rate = rate;
+}
+
+inline void VirtualMatrixPanel::setZoomFactor(int scale)
+{
+  if(scale < 5 && scale > 0)
+	_scale_factor = scale;
+
 }
 
 #ifndef NO_GFX
 inline void VirtualMatrixPanel::drawDisplayTest()
 {
+	// Write to the underlying panels only via the dma_display instance.
     this->display->setFont(&FreeSansBold12pt7b);
     this->display->setTextColor(this->display->color565(255, 255, 0));
     this->display->setTextSize(1);
@@ -339,7 +530,7 @@ inline void VirtualMatrixPanel::drawDisplayTest()
     {
         int top_left_x = (panel == 0) ? 0 : (panel * panelResX);
         this->display->drawRect(top_left_x, 0, panelResX, panelResY, this->display->color565(0, 255, 0));
-    this->display->setCursor(panel * panelResX, panelResY - 3);
+        this->display->setCursor((panel * panelResX) + 2, panelResY - 4);
         this->display->print((vmodule_cols * vmodule_rows) - panel);
     }
 }

src/platforms/esp32/esp32_i2s_parallel_dma.cpp

@@ -28,54 +28,35 @@ Modified heavily for the ESP32 HUB75 DMA library by:
 #include <driver/periph_ctrl.h>
 #include <soc/gpio_sig_map.h>
 
-#include <Arduino.h> // Need to make sure thi is uncommented to get ESP_LOG output on (Arduino) Serial output!!!!
+#if defined (ARDUINO_ARCH_ESP32)
+#include <Arduino.h>
+#endif
+
 #include <esp_err.h>
 #include <esp_log.h>
 
 // Get CPU freq function.
 #include <soc/rtc.h>
 
-/*
 
-callback shiftCompleteCallback;
-void setShiftCompleteCallback(callback f) {
-    shiftCompleteCallback = f;
-}
-
-volatile int  previousBufferOutputLoopCount = 0;
 	volatile bool previousBufferFree = true;
 
-static void IRAM_ATTR irq_hndlr(void* arg) { // if we use I2S1 (default)
+	static void IRAM_ATTR i2s_isr(void* arg) {
 
-        SET_PERI_REG_BITS(I2S_INT_CLR_REG(ESP32_I2S_DEVICE), I2S_OUT_EOF_INT_CLR_V, 1, I2S_OUT_EOF_INT_CLR_S);
-
-	previousBufferFree 		= true;
-
-
-        
-} // end irq_hndlr
-*/
-
-	volatile int DRAM_ATTR active_dma_buffer_output_count = 0;
-
-	void IRAM_ATTR irq_hndlr(void* arg) { 
+		// From original Sprite_TM Code
+		//REG_WRITE(I2S_INT_CLR_REG(1), (REG_READ(I2S_INT_RAW_REG(1)) & 0xffffffc0) | 0x3f);
 		
 		// Clear flag so we can get retriggered
 		SET_PERI_REG_BITS(I2S_INT_CLR_REG(ESP32_I2S_DEVICE), I2S_OUT_EOF_INT_CLR_V, 1, I2S_OUT_EOF_INT_CLR_S);                      
 		
-		active_dma_buffer_output_count++;
-
-	/*        
-		  if ( active_dma_buffer_output_count++ ) 
-		  {
-			  // Disable DMA chain EOF interrupt until next requested flipbuffer.
-			  // Otherwise we're needlessly generating interrupts we don't care about.
-			  //SET_PERI_REG_BITS(I2S_INT_ENA_REG(ESP32_I2S_DEVICE), I2S_OUT_EOF_INT_ENA_V, 0, I2S_OUT_EOF_INT_ENA_S);  
-			  active_dma_buffer_output_count = 0;
+		// at this point, the previously active buffer is free, go ahead and write to it
+		previousBufferFree = true;
+	}
+
+	bool DRAM_ATTR i2s_parallel_is_previous_buffer_free() {
+		return previousBufferFree;
 	}
-	*/
 
-	} // end irq_hndlr
 
 	// Static
 	i2s_dev_t* getDev()
@@ -221,22 +202,6 @@ static void IRAM_ATTR irq_hndlr(void* arg) { // if we use I2S1 (default)
     ESP_LOGD("ESP32/S2", "Requested output clock frequency: %d Mhz",  (freq/1000000));   		
 	
 	// What is the current CPU frequency?
-/*	
-    rtc_cpu_freq_config_t conf;
-    rtc_clk_cpu_freq_get_config(&conf);
-	auto source_freq = conf.source_freq_mhz;		
-	
-	
-    ESP_LOGD("ESP32/S2", "PLL (source) frequency: %d",  source_freq);    
-    ESP_LOGD("ESP32/S2", "CPU frequency: %d",  conf.freq_mhz);    
-*/	
-
-	/*
-    if(_div_num < 2 || _div_num > 16) {
-	
-      return false;
-    }
-	*/	
 
     // Calculate clock divider for ESP32-S2
     #if defined (CONFIG_IDF_TARGET_ESP32S2)      
@@ -412,24 +377,14 @@ static void IRAM_ATTR irq_hndlr(void* arg) { // if we use I2S1 (default)
     dev->timing.val = 0;
 
 
-    /* If we have double buffering, then allocate an interrupt service routine function
-     * that can be used for I2S0/I2S1 created interrupts.
-     */
-    if (_double_dma_buffer) {
+    // If we have double buffering, then allocate an interrupt service routine function
+    // that can be used for I2S0/I2S1 created interrupts.
 
-        // Get ISR setup 
-        esp_err_t err =  esp_intr_alloc(irq_source, 
-                                      (int)(ESP_INTR_FLAG_IRAM | ESP_INTR_FLAG_LEVEL1),
-                                      irq_hndlr, NULL, NULL);
+    // Setup I2S Interrupt
+    SET_PERI_REG_BITS(I2S_INT_ENA_REG(ESP32_I2S_DEVICE), I2S_OUT_EOF_INT_ENA_V, 1, I2S_OUT_EOF_INT_ENA_S);
 
-        if(err) {
-            ESP_LOGE("ESP32/S2", "init() Failed to setup interrupt request handeler.");    
-            return false;
-        }
-
-        // Don't do this here. Don't enable just yet.        
-        // dev->int_ena.out_eof = 1;
-    }
+    // Allocate a level 1 intterupt: lowest priority, as ISR isn't urgent and may take a long time to complete
+    esp_intr_alloc(irq_source, (int)(ESP_INTR_FLAG_IRAM | ESP_INTR_FLAG_LEVEL1), i2s_isr, NULL, NULL);
 
  
   #if defined (CONFIG_IDF_TARGET_ESP32S2)
@@ -438,7 +393,6 @@ static void IRAM_ATTR irq_hndlr(void* arg) { // if we use I2S1 (default)
       ESP_LOGD("ESP32-ORIG", "init() GPIO and clock configuration set for ESP32");    
   #endif
 
-
       return true;
   }
 
@@ -611,21 +565,16 @@ static void IRAM_ATTR irq_hndlr(void* arg) { // if we use I2S1 (default)
   } // end   
 
 
-  void Bus_Parallel16::flip_dma_output_buffer(int &current_back_buffer_id) // pass by reference so we can change in main matrixpanel class
+  void Bus_Parallel16::flip_dma_output_buffer(int buffer_id) // pass by reference so we can change in main matrixpanel class
   {
 	  
       // Setup interrupt handler which is focussed only on the (page 322 of Tech. Ref. Manual)
       // "I2S_OUT_EOF_INT: Triggered when rxlink has finished sending a packet" (when dma linked list with eof = 1 is hit)
-      //_dev->int_ena.out_eof = 1;      
-      _dev->int_ena.out_eof = 1; // enable interrupt
   	  
-      if ( current_back_buffer_id == 1) { 
+      if ( buffer_id == 1) { 
 
 	      _dmadesc_a[_dmadesc_last].qe.stqe_next = &_dmadesc_b[0]; // Start sending out _dmadesc_b (or buffer 1)
 
-        active_dma_buffer_output_count = 0;  
-        while (!active_dma_buffer_output_count) {}      		
-
         //fix _dmadesc_ loop issue #407
         //need to connect the up comming _dmadesc_ not the old one
         _dmadesc_b[_dmadesc_last].qe.stqe_next = &_dmadesc_b[0];
@@ -633,17 +582,16 @@ static void IRAM_ATTR irq_hndlr(void* arg) { // if we use I2S1 (default)
       } else { 
 	      
         _dmadesc_b[_dmadesc_last].qe.stqe_next = &_dmadesc_a[0]; 
-
-        active_dma_buffer_output_count = 0;  
-        while (!active_dma_buffer_output_count) {}    
-  
         _dmadesc_a[_dmadesc_last].qe.stqe_next = &_dmadesc_a[0];
 		
       }
-      current_back_buffer_id ^= 1;            
 
-      // Disable intterupt  
-      _dev->int_ena.out_eof = 0;      
+      previousBufferFree = false;  
+      //while (i2s_parallel_is_previous_buffer_free() == false) {}      
+      while (!previousBufferFree);
+
+           
+
 
   } // end flip
 

src/platforms/esp32/esp32_i2s_parallel_dma.hpp

@@ -49,13 +49,16 @@ Contributors:
 
 #define DMA_MAX (4096-4)
 
-#ifndef ESP32_I2S_DEVICE 
-  #define ESP32_I2S_DEVICE I2S_NUM_0	
-#endif 
-
 // The type used for this SoC
 #define HUB75_DMA_DESCRIPTOR_T lldesc_t
 
+
+#if defined (CONFIG_IDF_TARGET_ESP32S2)   
+#define ESP32_I2S_DEVICE I2S_NUM_0	
+#else
+#define ESP32_I2S_DEVICE I2S_NUM_1	
+#endif	
+
 //----------------------------------------------------------------------------
 
 void IRAM_ATTR irq_hndlr(void* arg);
@@ -119,7 +122,7 @@ i2s_dev_t* getDev();
     void dma_transfer_start();
     void dma_transfer_stop();
 
-    void flip_dma_output_buffer(int &current_back_buffer_id);
+    void flip_dma_output_buffer(int buffer_id);
   
   private:
 

src/platforms/esp32s3/gdma_lcd_parallel16.cpp

@@ -1,4 +1,4 @@
-/*
+/*********************************************************************************************
   Simple example of using the ESP32-S3's LCD peripheral for general-purpose
   (non-LCD) parallel data output with DMA. Connect 8 LEDs (or logic analyzer),
   cycles through a pattern among them at about 1 Hz.
@@ -15,7 +15,7 @@
 
  PLEASE SUPPORT THEM!
 
- */
+ ********************************************************************************************/
 #if __has_include (<hal/lcd_ll.h>)
 // Stop compile errors: /src/platforms/esp32s3/gdma_lcd_parallel16.hpp:64:10: fatal error: hal/lcd_ll.h: No such file or directory
 
@@ -26,22 +26,19 @@
   #include "gdma_lcd_parallel16.hpp"
   #include "esp_attr.h"
 
-//#if (CORE_DEBUG_LEVEL > ARDUHAL_LOG_LEVEL_NONE) || (ARDUHAL_LOG_LEVEL > ARDUHAL_LOG_LEVEL_NONE)  
-//  static const char* TAG = "gdma_lcd_parallel16";
-//#endif  
-
-  //static int _dmadesc_a_idx = 0;
-  //static int _dmadesc_b_idx = 0;  
-
-
-  dma_descriptor_t desc;          // DMA descriptor for testing
 /*
+  dma_descriptor_t desc;          // DMA descriptor for testing
+
   uint8_t data[8][312];           // Transmit buffer (2496 bytes total)  
   uint16_t* dmabuff2;
 */
+
+  DRAM_ATTR volatile bool previousBufferFree = true;
+ 
   // End-of-DMA-transfer callback
-  IRAM_ATTR bool dma_callback(gdma_channel_handle_t dma_chan,
+  IRAM_ATTR bool gdma_on_trans_eof_callback(gdma_channel_handle_t dma_chan,
                                     gdma_event_data_t *event_data, void *user_data) {
+                                        
   // This DMA callback seems to trigger a moment before the last data has
   // issued (buffering between DMA & LCD peripheral?), so pause a moment
   // before stopping LCD data out. The ideal delay may depend on the LCD
@@ -53,7 +50,10 @@
   // the transfer has finished, and the same flag is set later to trigger
   // the next transfer.
 
-    LCD_CAM.lcd_user.lcd_start = 0;
+    //LCD_CAM.lcd_user.lcd_start = 0;
+    
+    previousBufferFree = true;
+    
     return true;
   }  
 
@@ -83,7 +83,7 @@
 
     // Reset LCD bus
     LCD_CAM.lcd_user.lcd_reset = 1;
-    esp_rom_delay_us(100);
+    esp_rom_delay_us(1000);
 
 //    uint32_t lcd_clkm_div_num = ((160000000 + 1) / _cfg.bus_freq);
 //    ESP_LOGI("", "Clock divider is %d", lcd_clkm_div_num);     
@@ -109,10 +109,24 @@
     LCD_CAM.lcd_clock.lcd_clk_equ_sysclk = 1; // PCLK = CLK / 1 (... so 160Mhz still)
 
 
-    if (_cfg.psram_clk_override) // fastest speed I can get PSRAM to work before nothing shows
+    // https://esp32.com/viewtopic.php?f=5&t=24459&start=80#p94487
+    /* Re: ESP32-S3 LCD and I2S FULL documentation 
+     *  by ESP_Sprite » Fri Mar 25, 2022 2:06 am
+     *
+     *  Are you sure you are staying within the limits of the psram throughput? If GDMA can't fetch data fast 
+     *  enough it leads to corruption. Also keep in mind that worst case scenario, the gdma can only use half of 
+     *  the bandwidth of the psram peripheral (as it's round-robin shared with the CPUs).
+     */ 
+     
+    // Fastest speed I can get with Octoal PSRAM to work before nothing shows. Based on manual testing.
+    // If using an ESP32-S3 with slower (half the bandwidth) Q-SPI (Quad), then the divisor will need to be '20' (8Mhz) which wil be flickery! 
+    if (_cfg.psram_clk_override) 
     {
         ESP_LOGI("S3", "DMA buffer is on PSRAM. Limiting clockspeed....");   
-        LCD_CAM.lcd_clock.lcd_clkm_div_num = 10; //16mhz is the fasted the Octal PSRAM can support it seems 
+        //LCD_CAM.lcd_clock.lcd_clkm_div_num = 10; //16mhz is the fasted the Octal PSRAM can support it seems from faptastic's testing using an N8R8 variant (Octal SPI PSRAM).
+        
+        // https://github.com/mrfaptastic/ESP32-HUB75-MatrixPanel-DMA/issues/441#issuecomment-1513631890
+        LCD_CAM.lcd_clock.lcd_clkm_div_num = 12; // 13Mhz is the fastest when the DMA memory is needed to service other peripherals as well.
     }
     else
     {
@@ -120,12 +134,10 @@
       auto  freq     = (_cfg.bus_freq);
 
       auto  _div_num = 8; // 20Mhz 
-	  if (freq < 20000000L)
-	  {
+      if (freq < 20000000L) {
             _div_num = 12; // 13Mhz
       }
-	  else if (freq > 20000000L)
-	  {
+      else if (freq > 20000000L) {
             _div_num = 6; // 26Mhz --- likely to have noise without a good connection         
       }
 
@@ -133,8 +145,8 @@
       LCD_CAM.lcd_clock.lcd_clkm_div_num = _div_num; //3;      
 
     }
-     ESP_LOGI("S3", "Clock divider is %d", LCD_CAM.lcd_clock.lcd_clkm_div_num);   
 
+    ESP_LOGI("S3", "Clock divider is %d", LCD_CAM.lcd_clock.lcd_clkm_div_num);
     ESP_LOGD("S3", "Resulting output clock frequency: %ld Mhz",  (160000000L/LCD_CAM.lcd_clock.lcd_clkm_div_num)); 
 
 
@@ -150,13 +162,16 @@
     LCD_CAM.lcd_ctrl.lcd_rgb_mode_en = 0;    // i8080 mode (not RGB)
     LCD_CAM.lcd_rgb_yuv.lcd_conv_bypass = 0; // Disable RGB/YUV converter
     LCD_CAM.lcd_misc.lcd_next_frame_en = 0;  // Do NOT auto-frame
+
+    LCD_CAM.lcd_misc.lcd_bk_en = 1;          // https://esp32.com/viewtopic.php?t=24459&start=60#p91835
+    
     LCD_CAM.lcd_data_dout_mode.val = 0;      // No data delays
     LCD_CAM.lcd_user.lcd_always_out_en = 1;  // Enable 'always out' mode
     LCD_CAM.lcd_user.lcd_8bits_order = 0;    // Do not swap bytes
     LCD_CAM.lcd_user.lcd_bit_order = 0;      // Do not reverse bit order
     LCD_CAM.lcd_user.lcd_2byte_en = 1;       // 8-bit data mode
-    LCD_CAM.lcd_user.lcd_dummy = 0;          // Dummy phase(s) @ LCD start
-    LCD_CAM.lcd_user.lcd_dummy_cyclelen = 0; // 1 dummy phase
+    LCD_CAM.lcd_user.lcd_dummy = 1;          // Dummy phase(s) @ LCD start
+    LCD_CAM.lcd_user.lcd_dummy_cyclelen = 1; // 1+1 dummy phase
     LCD_CAM.lcd_user.lcd_cmd = 0;            // No command at LCD start
     // "Dummy phases" are initial LCD peripheral clock cycles before data
     // begins transmitting when requested. After much testing, determined
@@ -212,10 +227,11 @@
     // in a single DMA descriptor (max 4095 bytes). Large transfers would
     // require a linked list of descriptors, but here it's just one...
 
+/*
     desc.dw0.owner = DMA_DESCRIPTOR_BUFFER_OWNER_DMA;
     desc.dw0.suc_eof = 0; // Last descriptor
     desc.next = &desc;     // No linked list
-
+*/
    
     // Remaining descriptor elements are initialized before each DMA transfer.
 
@@ -236,37 +252,17 @@
     gdma_apply_strategy(dma_chan, &strategy_config);
 
     gdma_transfer_ability_t ability = {
-        .sram_trans_align = 4,
+        .sram_trans_align = 32,
         .psram_trans_align = 64,
     };
     gdma_set_transfer_ability(dma_chan, &ability);    
 
     // Enable DMA transfer callback
-    /*
     static gdma_tx_event_callbacks_t tx_cbs = {
-      .on_trans_eof = dma_callback
+       // .on_trans_eof is literally the only gdma tx event type available
+      .on_trans_eof = gdma_on_trans_eof_callback 
     };
     gdma_register_tx_event_callbacks(dma_chan, &tx_cbs, NULL);
-    */
-
-    // As mentioned earlier, the slowest clock we can get to the LCD
-    // peripheral is 40 MHz / 250 / 64 = 2500 Hz. To make an even slower
-    // bit pattern that's perceptible, we just repeat each value many
-    // times over. The pattern here just counts through each of 8 bits
-    // (each LED lights in sequence)...so to get this to repeat at about
-    // 1 Hz, each LED is lit for 2500/8 or 312 cycles, hence the
-    // data[8][312] declaration at the start of this code (it's not
-    // precisely 1 Hz because reality is messy, but sufficient for demo).
-    // In actual use, say controlling an LED matrix or NeoPixels, such
-    // shenanigans aren't necessary, as these operate at multiple MHz
-    // with much smaller clock dividers and can use 1 byte per datum.
-    /*
-    for (int i = 0; i < (sizeof(data) / sizeof(data[0])); i++) { // 0 to 7
-      for (int j = 0; j < sizeof(data[0]); j++) {            // 0 to 311
-        data[i][j] = 1 << i;
-      }
-    }
-    */
 
 
     // This uses a busy loop to wait for each DMA transfer to complete...
@@ -277,36 +273,14 @@
     // After much experimentation, each of these steps is required to get
     // a clean start on the next LCD transfer:
     gdma_reset(dma_chan);                 // Reset DMA to known state
+    esp_rom_delay_us(1000);
+     
     LCD_CAM.lcd_user.lcd_dout        = 1; // Enable data out
     LCD_CAM.lcd_user.lcd_update      = 1; // Update registers
     LCD_CAM.lcd_misc.lcd_afifo_reset = 1; // Reset LCD TX FIFO
 
-    // This program happens to send the same data over and over...but,
-    // if desired, one could fill the data buffer with a new bit pattern
-    // here, or point to a completely different buffer each time through.
-    // With two buffers, one can make best use of time by filling each
-    // with new data before the busy loop above, alternating between them.
-
-    // Reset elements of DMA descriptor. Just one in this code, long
-    // transfers would loop through a linked list.
-
-    /*
-    desc.dw0.size = desc.dw0.length = sizeof(data);
-    desc.buffer = dmabuff2; //data;
-    desc.next = &desc;
-*/
-
-
-/*
-    //gdma_start(dma_chan, (intptr_t)&desc); // Start DMA w/updated descriptor(s)
-    gdma_start(dma_chan, (intptr_t)&_dmadesc_a[0]); // Start DMA w/updated descriptor(s)
-    esp_rom_delay_us(100);              // Must 'bake' a moment before...
-    LCD_CAM.lcd_user.lcd_start = 1;        // Trigger LCD DMA transfer
-*/
-    
 
     return true; // no return val = illegal instruction
-
  }
 
 
@@ -379,7 +353,8 @@
     {
 
       _dmadesc_b[_dmadesc_b_idx].dw0.owner = DMA_DESCRIPTOR_BUFFER_OWNER_DMA;
-      _dmadesc_b[_dmadesc_b_idx].dw0.suc_eof = 0;
+      //_dmadesc_b[_dmadesc_b_idx].dw0.suc_eof = 0;   
+      _dmadesc_b[_dmadesc_b_idx].dw0.suc_eof = (_dmadesc_b_idx == (_dmadesc_count-1));
       _dmadesc_b[_dmadesc_b_idx].dw0.size = _dmadesc_b[_dmadesc_b_idx].dw0.length = size; //sizeof(data);
       _dmadesc_b[_dmadesc_b_idx].buffer = data; //data;
 
@@ -404,7 +379,8 @@
       }
 
       _dmadesc_a[_dmadesc_a_idx].dw0.owner = DMA_DESCRIPTOR_BUFFER_OWNER_DMA;
-      _dmadesc_a[_dmadesc_a_idx].dw0.suc_eof = 0;
+      //_dmadesc_a[_dmadesc_a_idx].dw0.suc_eof = 0;
+      _dmadesc_a[_dmadesc_a_idx].dw0.suc_eof = (_dmadesc_a_idx == (_dmadesc_count-1));    
       _dmadesc_a[_dmadesc_a_idx].dw0.size = _dmadesc_a[_dmadesc_a_idx].dw0.length = size; //sizeof(data);
       _dmadesc_a[_dmadesc_a_idx].buffer = data; //data;
 
@@ -441,12 +417,12 @@
   } // end   
 
 
-  void Bus_Parallel16::flip_dma_output_buffer(int &current_back_buffer_id)
+  void Bus_Parallel16::flip_dma_output_buffer(int back_buffer_id)
   {
 
    // if ( _double_dma_buffer == false) return;
 
-    if ( current_back_buffer_id == 1) // change across to everything 'b''
+    if ( back_buffer_id == 1) // change across to everything 'b''
     {
        _dmadesc_a[_dmadesc_count-1].next =  (dma_descriptor_t *) &_dmadesc_b[0];       
        _dmadesc_b[_dmadesc_count-1].next =  (dma_descriptor_t *) &_dmadesc_b[0];       
@@ -457,7 +433,14 @@
        _dmadesc_a[_dmadesc_count-1].next =  (dma_descriptor_t *) &_dmadesc_a[0];   
     }
 
-    current_back_buffer_id ^= 1;
+    //current_back_buffer_id ^= 1;
+    
+    previousBufferFree = false;  
+    
+    //while (i2s_parallel_is_previous_buffer_free() == false) {}      
+    while (!previousBufferFree);
+
+        
 
     
   } // end flip

src/platforms/esp32s3/gdma_lcd_parallel16.hpp

@@ -147,7 +147,7 @@
     void dma_transfer_start();
     void dma_transfer_stop();
 
-     void flip_dma_output_buffer(int &current_back_buffer_id);
+     void flip_dma_output_buffer(int back_buffer_id);
 
   private:
 

src/platforms/platform_detect.hpp

@@ -55,7 +55,8 @@ Modified heavily for the ESP32 HUB75 DMA library by:
 
   // Assume an ESP32 (the original 2015 version)
   // Same include as ESP32S3  
-  #pragma message "Compiling for original ESP32 (released 2016)"  
+  //#pragma message "Compiling for original ESP32 (released 2016)"  
+  
   #define ESP32_THE_ORIG 1	
   //#include "esp32/esp32_i2s_parallel_dma.hpp"
   //#include "esp32/esp32_i2s_parallel_dma.h"

testing/README.md

@@ -0,0 +1,5 @@
+Sample app to simulate the VirtualMatrixPanel class for testing / optimisation, without having to test with physical panels.
+
+```
+g++ -o myapp.exe virtual.cpp
+```

testing/baseline.hpp

@@ -0,0 +1,189 @@
+
+/**
+ * Calculate virtual->real co-ordinate mapping to underlying single chain of panels connected to ESP32.
+ * Updates the private class member variable 'coords', so no need to use the return value.
+ * Not thread safe, but not a concern for ESP32 sketch anyway... I think.
+ */
+// DO NOT CHANGE
+inline VirtualCoords VirtualMatrixPanelTest::getCoords_WorkingBaslineMarch2023(int16_t virt_x, int16_t virt_y)
+{
+    coords.x = coords.y = -1; // By defalt use an invalid co-ordinates that will be rejected by updateMatrixDMABuffer
+
+	if (virt_x < 0 || virt_x >= virtualResX || virt_y < 0 || virt_y >= virtualResY)
+	{ // Co-ordinates go from 0 to X-1 remember! otherwise they are out of range!
+		return coords;
+	}
+
+    // Do we want to rotate?
+    if (_rotate)
+    {
+        int16_t temp_x = virt_x;
+        virt_x = virt_y;
+        virt_y = virtualResY - 1 - temp_x;
+    }
+
+	int row  = (virt_y / panelResY); // 0 indexed
+	switch(panel_chain_type)
+	{
+			
+		case (CHAIN_TOP_RIGHT_DOWN): 
+		{
+            if ( (row % 2) == 1 ) 
+            { 	// upside down panel
+
+                //Serial.printf("Condition 1, row %d ", row);
+
+                // refersed for the row
+                coords.x = dmaResX - virt_x - (row*virtualResX);			
+
+                // y co-ord inverted within the panel
+                coords.y = panelResY - 1 - (virt_y % panelResY);	
+            
+
+            }
+            else
+            { 
+                //Serial.printf("Condition 2, row %d ", row);
+
+                coords.x =  ((vmodule_rows - (row+1))*virtualResX)+virt_x;
+                coords.y =  virt_y % panelResY;	
+                        
+            }
+
+		}
+			break;	
+
+
+		case (CHAIN_TOP_LEFT_DOWN): // OK -> modulus opposite of CHAIN_TOP_RIGHT_DOWN
+		{
+			if ( (row % 2) == 0 ) 
+			{ 	// refersed panel 
+
+                //Serial.printf("Condition 1, row %d ", row);
+				coords.x = dmaResX - virt_x - (row*virtualResX);			
+
+				// y co-ord inverted within the panel
+				coords.y = panelResY - 1 - (virt_y % panelResY);	
+
+			}
+			else
+			{ 
+                //Serial.printf("Condition 2, row %d ", row);
+				coords.x =  ((vmodule_rows - (row+1))*virtualResX)+virt_x;
+			    coords.y =  virt_y % panelResY;	
+						
+			}
+
+		}
+			break;	            
+			
+			
+
+
+		case (CHAIN_BOTTOM_LEFT_UP): 	// 
+		{
+            row = vmodule_rows - row - 1;
+		
+			if ( (row % 2) == 1 ) 
+			{ 	
+                // Serial.printf("Condition 1, row %d ", row);
+				coords.x =  ((vmodule_rows - (row+1))*virtualResX)+virt_x;
+				coords.y = virt_y % panelResY;	
+ 
+			}
+			else
+			{  // inverted panel                     
+
+                // Serial.printf("Condition 2, row %d ", row);
+				coords.x =  dmaResX - (row*virtualResX) - virt_x;         
+				coords.y = panelResY - 1 - (virt_y % panelResY);
+			}
+			
+		}
+			break;
+	
+		case (CHAIN_BOTTOM_RIGHT_UP): 	// OK -> modulus opposite of CHAIN_BOTTOM_LEFT_UP
+		{
+            row = vmodule_rows - row - 1;
+		
+			if ( (row % 2) == 0 ) 
+			{ 	// right side up
+
+                // Serial.printf("Condition 1, row %d ", row);
+				// refersed for the row
+				coords.x =  ((vmodule_rows - (row+1))*virtualResX)+virt_x;
+				coords.y = virt_y % panelResY;	
+ 
+			}
+			else
+			{  // inverted panel                     
+
+                // Serial.printf("Condition 2, row %d ", row);
+				coords.x =  dmaResX - (row*virtualResX) - virt_x;         
+				coords.y = panelResY - 1 - (virt_y % panelResY);
+			}
+			
+		}
+			break;
+						
+
+		default:
+            return coords;
+			break;
+			
+	} // end switch
+	
+
+
+  /* START: Pixel remapping AGAIN to convert TWO parallel scanline output that the
+   *        the underlying hardware library is designed for (because
+   *        there's only 2 x RGB pins... and convert this to 1/4 or something
+   */
+  if (panel_scan_rate == FOUR_SCAN_32PX_HIGH)
+  {
+    /* Convert Real World 'VirtualMatrixPanel' co-ordinates (i.e. Real World pixel you're looking at
+       on the panel or chain of panels, per the chaining configuration) to a 1/8 panels
+       double 'stretched' and 'squished' coordinates which is what needs to be sent from the
+       DMA buffer.
+
+       Note: Look at the FourScanPanel example code and you'll see that the DMA buffer is setup
+       as if the panel is 2 * W and 0.5 * H !
+    */
+
+    if ((virt_y & 8) == 0)
+    {
+      coords.x += ((coords.x / panelResX) + 1) * panelResX; // 1st, 3rd 'block' of 8 rows of pixels, offset by panel width in DMA buffer
+    }
+    else
+    {
+      coords.x += (coords.x / panelResX) * panelResX; // 2nd, 4th 'block' of 8 rows of pixels, offset by panel width in DMA buffer
+    }
+
+    // http://cpp.sh/4ak5u
+    // Real number of DMA y rows is half reality
+    // coords.y = (y / 16)*8 + (y & 0b00000111);
+    coords.y = (virt_y >> 4) * 8 + (virt_y & 0b00000111);
+
+  }
+  else if (panel_scan_rate == FOUR_SCAN_16PX_HIGH)
+  {
+    if ((virt_y & 8) == 0)
+    {
+      coords.x += (panelResX >> 2) * (((coords.x & 0xFFF0) >> 4) + 1); // 1st, 3rd 'block' of 8 rows of pixels, offset by panel width in DMA buffer
+    }
+    else
+    {
+      coords.x += (panelResX >> 2) * (((coords.x & 0xFFF0) >> 4)); // 2nd, 4th 'block' of 8 rows of pixels, offset by panel width in DMA buffer
+    }
+
+    if (virt_y < 32)
+      coords.y = (virt_y >> 4) * 8 + (virt_y & 0b00000111);
+    else
+    {
+      coords.y = ((virt_y - 32) >> 4) * 8 + (virt_y & 0b00000111);
+      coords.x += 256;
+    }
+  }
+
+  return coords;
+}

testing/virtual.cpp

@@ -0,0 +1,459 @@
+#include <iostream>
+#include <string>
+#include <list>
+
+
+struct VirtualCoords
+{
+  int16_t x;
+  int16_t y;
+  int16_t virt_row; // chain of panels row
+  int16_t virt_col; // chain of panels col
+
+  VirtualCoords() : x(0), y(0)
+  {
+  }
+};
+
+enum PANEL_SCAN_RATE
+{
+  NORMAL_TWO_SCAN, NORMAL_ONE_SIXTEEN, // treated as the same
+  FOUR_SCAN_32PX_HIGH,
+  FOUR_SCAN_16PX_HIGH
+};
+
+// Chaining approach... From the perspective of the DISPLAY / LED side of the chain of panels.
+enum PANEL_CHAIN_TYPE
+{
+	CHAIN_TOP_LEFT_DOWN,
+	CHAIN_TOP_RIGHT_DOWN,
+	CHAIN_BOTTOM_LEFT_UP,
+	CHAIN_BOTTOM_RIGHT_UP,
+	CHAIN_TOP_RIGHT_DOWN_ZZ, /// ZigZag chaining. Might need a big ass cable to do this, all panels right way up.
+	CHAIN_BOTTOM_RIGHT_UP_ZZ
+};
+
+
+class VirtualMatrixPanelTest
+{
+
+public:
+  VirtualMatrixPanelTest(int _vmodule_rows, int _vmodule_cols, int _panelResX, int _panelResY, PANEL_CHAIN_TYPE _panel_chain_type = CHAIN_TOP_RIGHT_DOWN)
+  {
+
+    panelResX = _panelResX;
+    panelResY = _panelResY;
+
+    vmodule_rows = _vmodule_rows;
+    vmodule_cols = _vmodule_cols;
+
+    virtualResX = vmodule_cols * _panelResX;
+    virtualResY = vmodule_rows * _panelResY;
+
+    dmaResX = panelResX * vmodule_rows * vmodule_cols;
+	
+	panel_chain_type = _panel_chain_type;
+
+    /* Virtual Display width() and height() will return a real-world value. For example:
+     * Virtual Display width: 128
+     * Virtual Display height: 64
+     *
+     * So, not values that at 0 to X-1
+     */
+
+    coords.x = coords.y = -1; // By default use an invalid co-ordinates that will be rejected by updateMatrixDMABuffer
+	
+	switch (panel_chain_type) {
+		case CHAIN_TOP_LEFT_DOWN:
+			chain_type_str = "CHAIN_TOP_LEFT_DOWN";
+			break;
+
+		case CHAIN_TOP_RIGHT_DOWN:
+			chain_type_str = "CHAIN_TOP_RIGHT_DOWN";
+			break;
+			
+		case CHAIN_TOP_RIGHT_DOWN_ZZ:
+			chain_type_str = "CHAIN_TOP_RIGHT_DOWN_ZZ";
+			break;			
+			
+		case CHAIN_BOTTOM_RIGHT_UP:
+			chain_type_str = "CHAIN_BOTTOM_RIGHT_UP";
+			break;
+			
+		case CHAIN_BOTTOM_LEFT_UP:
+			chain_type_str = "CHAIN_BOTTOM_LEFT_UP";
+			break;	
+
+		default:
+			chain_type_str = "WTF!";
+			break;					
+	}
+	std::cout << "\n\n***************************************************************************\n";	
+	std::cout << "Chain type: " << chain_type_str << " ";
+	std::printf("Testing chain of panels of %d rows, %d columns, %d px by %d px resolution. \n\n", vmodule_rows, vmodule_cols, panelResX, panelResX, panelResY);
+	
+	
+  }
+
+  // equivalent methods of the matrix library so it can be just swapped out.
+  void drawPixel(int16_t x, int16_t y, int16_t expected_x, int16_t expected_y);
+
+  std::string chain_type_str = "UNKNOWN";
+  
+  // Internal co-ord conversion function
+  VirtualCoords getCoords_Dev(int16_t x, int16_t y);
+  
+  VirtualCoords getCoords_WorkingBaslineMarch2023(int16_t x, int16_t y);
+  
+  VirtualCoords coords;
+  
+	
+private:
+
+  int16_t virtualResX;
+  int16_t virtualResY;
+
+  int16_t vmodule_rows;
+  int16_t vmodule_cols;
+
+  int16_t panelResX;
+  int16_t panelResY;
+
+  int16_t dmaResX; // The width of the chain in pixels (as the DMA engine sees it)
+
+  PANEL_CHAIN_TYPE 	panel_chain_type;    
+  PANEL_SCAN_RATE 	panel_scan_rate    = NORMAL_TWO_SCAN;    
+    
+  bool _rotate = false;
+
+}; // end Class header
+
+#include "baseline.hpp"
+
+/**
+ * Development version for testing.
+ */
+inline VirtualCoords VirtualMatrixPanelTest::getCoords_Dev(int16_t virt_x, int16_t virt_y)
+{
+    coords.x = coords.y = -1; // By defalt use an invalid co-ordinates that will be rejected by updateMatrixDMABuffer
+
+	if (virt_x < 0 || virt_x >= virtualResX || virt_y < 0 || virt_y >= virtualResY)
+	{ // Co-ordinates go from 0 to X-1 remember! otherwise they are out of range!
+		return coords;
+	}
+
+    // Do we want to rotate?
+    if (_rotate)
+    {
+        int16_t temp_x = virt_x;
+        virt_x = virt_y;
+        virt_y = virtualResY - 1 - temp_x;
+    }
+
+	int row  = (virt_y / panelResY); // 0 indexed
+	switch(panel_chain_type)
+	{
+			
+		case (CHAIN_TOP_RIGHT_DOWN): 
+		{
+            if ( (row % 2) == 1 ) 
+            { 	// upside down panel
+
+                //Serial.printf("Condition 1, row %d ", row);
+
+                // refersed for the row
+                coords.x = dmaResX - virt_x - (row*virtualResX);			
+
+                // y co-ord inverted within the panel
+                coords.y = panelResY - 1 - (virt_y % panelResY);	
+            
+
+            }
+            else
+            { 
+                //Serial.printf("Condition 2, row %d ", row);
+                coords.x =  ((vmodule_rows - (row+1))*virtualResX)+virt_x;
+                coords.y =  virt_y % panelResY;	
+                        
+            }
+
+		}
+			break;	
+
+
+		case (CHAIN_TOP_LEFT_DOWN): // OK -> modulus opposite of CHAIN_TOP_RIGHT_DOWN
+		{
+			if ( (row % 2) == 0 ) 
+			{ 	// refersed panel 
+
+                //Serial.printf("Condition 1, row %d ", row);
+				coords.x = dmaResX - virt_x - (row*virtualResX);			
+
+				// y co-ord inverted within the panel
+				coords.y = panelResY - 1 - (virt_y % panelResY);	
+
+			}
+			else
+			{ 
+                //Serial.printf("Condition 2, row %d ", row);
+				coords.x =  ((vmodule_rows - (row+1))*virtualResX)+virt_x;
+			    coords.y =  virt_y % panelResY;	
+						
+			}
+
+		}
+			break;	            
+			
+			
+
+
+		case (CHAIN_BOTTOM_LEFT_UP): 	// 
+		{
+            row = vmodule_rows - row - 1;
+		
+			if ( (row % 2) == 1 ) 
+			{ 	
+                // Serial.printf("Condition 1, row %d ", row);
+				coords.x =  ((vmodule_rows - (row+1))*virtualResX)+virt_x;
+				coords.y = virt_y % panelResY;	
+ 
+			}
+			else
+			{  // inverted panel                     
+
+                // Serial.printf("Condition 2, row %d ", row);
+				coords.x =  dmaResX - (row*virtualResX) - virt_x;         
+				coords.y = panelResY - 1 - (virt_y % panelResY);
+			}
+			
+		}
+			break;
+	
+		case (CHAIN_BOTTOM_RIGHT_UP): 	// OK -> modulus opposite of CHAIN_BOTTOM_LEFT_UP
+		{
+            row = vmodule_rows - row - 1;
+		
+			if ( (row % 2) == 0 ) 
+			{ 	// right side up
+
+                // Serial.printf("Condition 1, row %d ", row);
+				// refersed for the row
+				coords.x =  ((vmodule_rows - (row+1))*virtualResX)+virt_x;
+				coords.y = virt_y % panelResY;	
+ 
+			}
+			else
+			{  // inverted panel                     
+
+                // Serial.printf("Condition 2, row %d ", row);
+				coords.x =  dmaResX - (row*virtualResX) - virt_x;         
+				coords.y = panelResY - 1 - (virt_y % panelResY);
+			}
+			
+		}
+			break;
+			
+		case CHAIN_TOP_RIGHT_DOWN_ZZ:
+		{
+			//	Right side up. Starting from top left all the way down.
+			//  Connected in a Zig Zag manner = some long ass cables being used potentially
+		
+			//Serial.printf("Condition 2, row %d ", row);
+			coords.x =  ((vmodule_rows - (row+1))*virtualResX)+virt_x;
+			coords.y =  virt_y % panelResY;				
+			
+		}
+		
+		case CHAIN_BOTTOM_RIGHT_UP_ZZ:
+		{
+			//	Right side up. Starting from top left all the way down.
+			//  Connected in a Zig Zag manner = some long ass cables being used potentially
+		
+			//Serial.printf("Condition 2, row %d ", row);
+			coords.x =  (row*virtualResX)+virt_x;
+			coords.y =  virt_y % panelResY;				
+			
+		}
+								
+						
+						
+
+		default:
+            return coords;
+			break;
+			
+	} // end switch
+	
+
+
+  /* START: Pixel remapping AGAIN to convert TWO parallel scanline output that the
+   *        the underlying hardware library is designed for (because
+   *        there's only 2 x RGB pins... and convert this to 1/4 or something
+   */
+  if (panel_scan_rate == FOUR_SCAN_32PX_HIGH)
+  {
+    /* Convert Real World 'VirtualMatrixPanel' co-ordinates (i.e. Real World pixel you're looking at
+       on the panel or chain of panels, per the chaining configuration) to a 1/8 panels
+       double 'stretched' and 'squished' coordinates which is what needs to be sent from the
+       DMA buffer.
+
+       Note: Look at the FourScanPanel example code and you'll see that the DMA buffer is setup
+       as if the panel is 2 * W and 0.5 * H !
+    */
+
+    if ((virt_y & 8) == 0)
+    {
+      coords.x += ((coords.x / panelResX) + 1) * panelResX; // 1st, 3rd 'block' of 8 rows of pixels, offset by panel width in DMA buffer
+    }
+    else
+    {
+      coords.x += (coords.x / panelResX) * panelResX; // 2nd, 4th 'block' of 8 rows of pixels, offset by panel width in DMA buffer
+    }
+
+    // http://cpp.sh/4ak5u
+    // Real number of DMA y rows is half reality
+    // coords.y = (y / 16)*8 + (y & 0b00000111);
+    coords.y = (virt_y >> 4) * 8 + (virt_y & 0b00000111);
+
+  }
+  else if (panel_scan_rate == FOUR_SCAN_16PX_HIGH)
+  {
+    if ((virt_y & 8) == 0)
+    {
+      coords.x += (panelResX >> 2) * (((coords.x & 0xFFF0) >> 4) + 1); // 1st, 3rd 'block' of 8 rows of pixels, offset by panel width in DMA buffer
+    }
+    else
+    {
+      coords.x += (panelResX >> 2) * (((coords.x & 0xFFF0) >> 4)); // 2nd, 4th 'block' of 8 rows of pixels, offset by panel width in DMA buffer
+    }
+
+    if (virt_y < 32)
+      coords.y = (virt_y >> 4) * 8 + (virt_y & 0b00000111);
+    else
+    {
+      coords.y = ((virt_y - 32) >> 4) * 8 + (virt_y & 0b00000111);
+      coords.x += 256;
+    }
+  }
+
+  return coords;
+}
+
+bool check(VirtualCoords expected, VirtualCoords result, int x = -1, int y = -1)
+{
+
+	  if ( result.x != expected.x || result.y != expected.y )
+	  {
+		  std::printf("Requested (%d, %d) -> expecting physical (%d, %d) got (%d, %d).", x, y, expected.x, expected.y, result.x, result.y);
+		  std::cout << "\t *** FAIL ***\n ";
+		  std::cout << "\n";
+
+		  return false;
+	  }
+	  else
+	  {
+		  return true;
+	  }	
+}
+
+
+main(int argc, char* argv[])
+{
+    std::cout << "Starting Testing...\n";
+	
+	std::list <PANEL_CHAIN_TYPE> chain_t_test_list { 	CHAIN_TOP_LEFT_DOWN,	CHAIN_TOP_RIGHT_DOWN,	CHAIN_BOTTOM_LEFT_UP, 	CHAIN_BOTTOM_RIGHT_UP };
+	
+
+	// Draw pixel at virtual position 70x, 70y = 
+	// x, y  x, y
+	
+	// x == horizontal
+	// y = vert :-)
+	
+	// 192 x 192 pixel virtual display
+	int rows = 3;
+	int cols = 3;
+	int panel_width_x 	= 64;
+	int panel_height_y	= 64;
+	
+	std::string panel_scan_type = "NORMAL_TWO_SCAN";
+	
+	for (auto chain_t : chain_t_test_list) {
+
+
+			VirtualMatrixPanelTest test = VirtualMatrixPanelTest(rows,cols,panel_width_x,panel_height_y, chain_t);
+			int pass_counter = 0;
+			int fail_counter = 0;
+			for (int16_t x = 0; x < panel_width_x*cols; x++)
+			{
+				for (int16_t y = 0; y < panel_height_y*rows; y++)
+				{
+					VirtualCoords expected = test.getCoords_WorkingBaslineMarch2023(x,y);
+					VirtualCoords result   = test.getCoords_Dev(x,y);
+					
+					bool chk_result = check(expected, result, x, y);
+
+					  if ( chk_result )
+					  { 
+						  fail_counter++;
+					  }
+					  else
+					  {
+						  pass_counter++;
+					  }
+				}
+			}
+			
+			if ( fail_counter > 0) {
+				std::printf("ERROR: %d tests failed.\n", fail_counter); 
+			} else{
+				std::printf("SUCCESS: %d coord tests passed.\n", pass_counter); 		
+			}
+			
+	}	// end chain type test list
+	
+	
+	std::cout << "Performing NON-SERPENTINE (ZIG ZAG) TEST";
+	
+	rows = 3;
+	cols = 1;
+	panel_width_x 	= 64;
+	panel_height_y	= 64;	
+	
+	VirtualMatrixPanelTest test = VirtualMatrixPanelTest(rows,cols,panel_width_x,panel_height_y, CHAIN_TOP_RIGHT_DOWN_ZZ);
+	
+	// CHAIN_TOP_RIGHT_DOWN_ZZ test 1
+	// (x,y)
+	VirtualCoords result   = test.getCoords_Dev(0,0);	
+	VirtualCoords expected; expected.x = 64*2; expected.y = 0;
+    std::printf("Expected physical (%d, %d) got (%d, %d).\n", expected.x, expected.y, result.x, result.y);
+
+	// CHAIN_TOP_RIGHT_DOWN_ZZ test 2
+	result   = test.getCoords_Dev(10,64*3-1);	
+	expected.x = 10; expected.y = 63; 
+    std::printf("Expected physical (%d, %d) got (%d, %d).\n", expected.x, expected.y, result.x, result.y);
+		
+		
+	// CHAIN_TOP_RIGHT_DOWN_ZZ test 3
+	result   = test.getCoords_Dev(16,64*2-1);	
+	expected.x = 80; expected.y = 63; 
+    std::printf("Expected physical (%d, %d) got (%d, %d).\n", expected.x, expected.y, result.x, result.y);
+	
+		
+		
+	// CHAIN_BOTTOM_RIGHT_UP_ZZ test 4
+	result   = test.getCoords_Dev(0,0);	
+	expected.x = 0; expected.y = 0; 
+    std::printf("Expected physical (%d, %d) got (%d, %d).\n", expected.x, expected.y, result.x, result.y);	
+			
+	// CHAIN_BOTTOM_RIGHT_UP_ZZ test 4
+	result   = test.getCoords_Dev(63,64);	
+	expected.x = 64*2-1; expected.y = 0; 
+    std::printf("Expected physical (%d, %d) got (%d, %d).\n", expected.x, expected.y, result.x, result.y);	
+				
+				
+	
+	std::cout << "\n\n";
+
+    return 0;
+}