minor fixes and comments

Signed-off-by: Emil Muratov <gpm@hotplug.ru>

ESP32-HUB75-MatrixPanel-I2S-DMA.cpp

@@ -200,13 +200,16 @@ bool MatrixPanel_I2S_DMA::allocateDMAmemory()
     for(int i=lsbMsbTransitionBit + 1; i<PIXEL_COLOR_DEPTH_BITS; i++) {
         numDMAdescriptorsPerRow += (1<<(i - lsbMsbTransitionBit - 1));
     }
+    #if SERIAL_DEBUG
+      Serial.printf("Recalculated number of DMA descriptors per row: %d\n", numDMAdescriptorsPerRow);
+    #endif
 
     // Refer to 'DMA_LL_PAYLOAD_SPLIT' code in configureDMA() below to understand why this exists.
     // numDMAdescriptorsPerRow is also used to calcaulte descount which is super important in i2s_parallel_config_t SoC DMA setup. 
     if ( sizeof(rowColorDepthStruct) > DMA_MAX ) {
 
         #if SERIAL_DEBUG  
-          Serial.println("Split DMA payload required.");        
+          Serial.printf("rowColorDepthStruct struct is too large, split DMA payload required. Adding %d DMA descriptors\n", PIXEL_COLOR_DEPTH_BITS-1);
 		    #endif
 
         numDMAdescriptorsPerRow += PIXEL_COLOR_DEPTH_BITS-1; 
@@ -273,7 +276,7 @@ bool MatrixPanel_I2S_DMA::allocateDMAmemory()
 
     return true;
 
-} // end initMatrixDMABuffer()
+} // end allocateDMAmemory()
 
 
 
@@ -301,7 +304,7 @@ void MatrixPanel_I2S_DMA::configureDMA(int r1_pin, int  g1_pin, int  b1_pin, int
         rowColorDepthStruct *fb_malloc_ptr = matrix_row_framebuffer_malloc[row]; 
 
         #if SERIAL_DEBUG          
-          Serial.printf("DMA payload of %d bytes. DMA_MAX is %d.\r\n", sizeof(rowBitStruct) * PIXEL_COLOR_DEPTH_BITS, DMA_MAX);
+          Serial.printf("Row %d DMA payload of %d bytes. DMA_MAX is %d.\r\n", row, sizeof(rowBitStruct) * PIXEL_COLOR_DEPTH_BITS, DMA_MAX);
         #endif        
 
         
@@ -389,13 +392,6 @@ void MatrixPanel_I2S_DMA::configureDMA(int r1_pin, int  g1_pin, int  b1_pin, int
     }
 
     
-/*
-    //End markers
-    dmadesc_a[desccount-1].eof = 1;
-    dmadesc_b[desccount-1].eof = 1;
-    dmadesc_a[desccount-1].qe.stqe_next=(lldesc_t*)&dmadesc_a[0];
-    dmadesc_b[desccount-1].qe.stqe_next=(lldesc_t*)&dmadesc_b[0];   
-*/
     //Serial.printf("Performing I2S setup.\n");
 	
     i2s_parallel_config_t cfg={
@@ -655,6 +651,7 @@ void MatrixPanel_I2S_DMA::updateMatrixDMABuffer(uint8_t red, uint8_t green, uint
  */
 void MatrixPanel_I2S_DMA::shiftDriver(const shift_driver _drv, const int dma_r1_pin, const int dma_g1_pin, const int dma_b1_pin, const int dma_r2_pin, const int dma_g2_pin, const int dma_b2_pin, const int dma_a_pin, const int dma_b_pin, const int dma_c_pin, const int dma_d_pin, const int dma_e_pin, const int dma_lat_pin, const int dma_oe_pin, const int dma_clk_pin){
     switch (_drv){
+    case ICN2038S:
     case FM6124:
     case FM6126A:
     {

ESP32-HUB75-MatrixPanel-I2S-DMA.h

@@ -114,7 +114,7 @@
 
 // RGB Panel Constants / Calculated Values
 #define COLOR_CHANNELS_PER_PIXEL 3 
-#define PIXELS_PER_ROW ((MATRIX_WIDTH * MATRIX_HEIGHT) / MATRIX_HEIGHT) // = 64
+#define PIXELS_PER_ROW      MATRIX_WIDTH      // number of all pixels in a row of chained modules 
 //#define PIXEL_COLOR_DEPTH_BITS (MATRIX_COLOR_DEPTH/COLOR_CHANNELS_PER_PIXEL)  //  = 8
 #define ROWS_PER_FRAME (MATRIX_HEIGHT/MATRIX_ROWS_IN_PARALLEL) //  = 16
 
@@ -169,13 +169,17 @@ typedef struct RGB24 {
     uint8_t blue;
 } RGB24;
 
-enum shift_driver {SHIFT=0, FM6124, FM6126A};
+/** 
+ * Enumeration of hardware-specific chips
+ * used to drive matrix modules
+ */
+enum shift_driver {SHIFT=0, FM6124, FM6126A, ICN2038S};
 
 /***************************************************************************************/   
 // Used by val2PWM
 //C/p'ed from https://ledshield.wordpress.com/2012/11/13/led-brightness-to-your-eye-gamma-correction-no/
 // Example calculator: https://gist.github.com/mathiasvr/19ce1d7b6caeab230934080ae1f1380e
-const uint16_t lumConvTab[]={ 
+const uint8_t lumConvTab[]={ 
     0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 5, 5, 5, 5, 5, 6, 6, 6, 6, 6, 7, 7, 7, 7, 8, 8, 8, 8, 9, 9, 9, 10, 10, 10, 11, 11, 11, 12, 12, 12, 13, 13, 13, 14, 14, 14, 15, 15, 16, 16, 17, 17, 17, 18, 18, 19, 19, 20, 20, 21, 21, 22, 22, 23, 23, 24, 24, 25, 25, 26, 27, 27, 28, 28, 29, 30, 30, 31, 31, 32, 33, 33, 34, 35, 35, 36, 37, 38, 38, 39, 40, 41, 41, 42, 43, 44, 45, 45, 46, 47, 48, 49, 50, 51, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 73, 74, 75, 76, 77, 78, 80, 81, 82, 83, 84, 86, 87, 88, 90, 91, 92, 93, 95, 96, 98, 99, 100, 102, 103, 105, 106, 107, 109, 110, 112, 113, 115, 116, 118, 120, 121, 123, 124, 126, 128, 129, 131, 133, 134, 136, 138, 139, 141, 143, 145, 146, 148, 150, 152, 154, 156, 157, 159, 161, 163, 165, 167, 169, 171, 173, 175, 177, 179, 181, 183, 185, 187, 189, 192, 194, 196, 198, 200, 203, 205, 207, 209, 212, 214, 216, 218, 221, 223, 226, 228, 230, 233, 235, 238, 240, 243, 245, 248, 250, 253, 255, 255};
 
 /***************************************************************************************/   
@@ -237,9 +241,11 @@ class MatrixPanel_I2S_DMA : public Adafruit_GFX {
 
       // Flush the DMA buffers prior to configuring DMA - Avoid visual artefacts on boot.
       clearScreen(); // Must fill the DMA buffer with the initial output bit sequence or the panel will display garbage
-      flipDMABuffer(); // flip to backbuffer 1
+      if (double_buffering_enabled){
-      clearScreen(); // Must fill the DMA buffer with the initial output bit sequence or the panel will display garbage
+        flipDMABuffer(); // flip to backbuffer 1
-      flipDMABuffer(); // backbuffer 0
+        clearScreen(); // Must fill the DMA buffer with the initial output bit sequence or the panel will display garbage
+        flipDMABuffer(); // backbuffer 0
+      }
       
       // Setup the ESP32 DMA Engine. Sprite_TM built this stuff.
       configureDMA(dma_r1_pin, dma_g1_pin, dma_b1_pin, dma_r2_pin, dma_g2_pin, dma_b2_pin, dma_a_pin,  dma_b_pin, dma_c_pin, dma_d_pin, dma_e_pin, dma_lat_pin,  dma_oe_pin,   dma_clk_pin ); //DMA and I2S configuration and setup