FM6126A init function optimized

some research on brightness control noted in FM6126A.md

Signed-off-by: Emil Muratov <gpm@hotplug.ru>
This commit is contained in:
Emil Muratov 2020-12-05 03:18:25 +03:00
parent 32f5cbab73
commit 7d5f445629
2 changed files with 88 additions and 61 deletions

View file

@ -791,91 +791,50 @@ void MatrixPanel_I2S_DMA::shiftDriver(const shift_driver _drv, const int dma_r1_
#if SERIAL_DEBUG
Serial.println( F("MatrixPanel_I2S_DMA - initializing FM6124 driver..."));
#endif
int C12[16] = {0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1};
int C13[16] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0};
bool REG1[16] = {0,0,0,0,0, 1,1,1,1,1,1, 0,0,0,0,0}; // this sets global matrix brighness power
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
pinMode(dma_r1_pin, OUTPUT);
pinMode(dma_g1_pin, OUTPUT);
pinMode(dma_b1_pin, OUTPUT);
pinMode(dma_r2_pin, OUTPUT);
pinMode(dma_g2_pin, OUTPUT);
pinMode(dma_b2_pin, OUTPUT);
pinMode(dma_a_pin, OUTPUT);
pinMode(dma_b_pin, OUTPUT);
pinMode(dma_c_pin, OUTPUT);
pinMode(dma_d_pin, OUTPUT);
pinMode(dma_e_pin, OUTPUT);
pinMode(dma_clk_pin, OUTPUT);
pinMode(dma_lat_pin, OUTPUT);
pinMode(dma_oe_pin, OUTPUT);
for (uint8_t _pin:{dma_r1_pin, dma_r2_pin, dma_g1_pin, dma_g2_pin, dma_b1_pin, dma_b2_pin, dma_clk_pin, dma_lat_pin, dma_oe_pin})
pinMode(_pin, OUTPUT);
// Send Data to control register 11
digitalWrite(dma_oe_pin, HIGH); // Display reset
digitalWrite(dma_oe_pin, HIGH); // Disable Display
digitalWrite(dma_lat_pin, LOW);
digitalWrite(dma_clk_pin, LOW);
// Send Data to control register REG1
// this sets the matrix brightness actually
for (int l = 0; l < MATRIX_WIDTH; l++){
int y = l % 16;
digitalWrite(dma_r1_pin, LOW);
digitalWrite(dma_g1_pin, LOW);
digitalWrite(dma_b1_pin, LOW);
digitalWrite(dma_r2_pin, LOW);
digitalWrite(dma_g2_pin, LOW);
digitalWrite(dma_b2_pin, LOW);
for (uint8_t _pin:{dma_r1_pin, dma_r2_pin, dma_g1_pin, dma_g2_pin, dma_b1_pin, dma_b2_pin})
digitalWrite(_pin, REG1[l%16]); // we have 16 bits shifters and write the same value all over the matrix array
if (C12[y] == 1){
digitalWrite(dma_r1_pin, HIGH);
digitalWrite(dma_g1_pin, HIGH);
digitalWrite(dma_b1_pin, HIGH);
digitalWrite(dma_r2_pin, HIGH);
digitalWrite(dma_g2_pin, HIGH);
digitalWrite(dma_b2_pin, HIGH);
}
if (l > MATRIX_WIDTH - 12){
if (l > MATRIX_WIDTH - 12){ // pull the latch 12 clocks before the end of matrix so that REG1 starts counting to save the value
digitalWrite(dma_lat_pin, HIGH);
} else {
digitalWrite(dma_lat_pin, LOW);
}
digitalWrite(dma_clk_pin, HIGH);
digitalWrite(dma_clk_pin, HIGH); // 1-clock pulse
digitalWrite(dma_clk_pin, LOW);
}
// drop the latch and save data to the REG1 all over the FM6124 chips
digitalWrite(dma_lat_pin, LOW);
digitalWrite(dma_clk_pin, LOW);
// Send Data to control register 12
// Send Data to control register REG2 (enable LED output)
for (int l = 0; l < MATRIX_WIDTH; l++){
int y = l % 16;
digitalWrite(dma_r1_pin, LOW);
digitalWrite(dma_g1_pin, LOW);
digitalWrite(dma_b1_pin, LOW);
digitalWrite(dma_r2_pin, LOW);
digitalWrite(dma_g2_pin, LOW);
digitalWrite(dma_b2_pin, LOW);
for (uint8_t _pin:{dma_r1_pin, dma_r2_pin, dma_g1_pin, dma_g2_pin, dma_b1_pin, dma_b2_pin})
digitalWrite(_pin, REG2[l%16]); // we have 16 bits shifters and we write the same value all over the matrix array
if (C13[y] == 1){
digitalWrite(dma_r1_pin, HIGH);
digitalWrite(dma_g1_pin, HIGH);
digitalWrite(dma_b1_pin, HIGH);
digitalWrite(dma_r2_pin, HIGH);
digitalWrite(dma_g2_pin, HIGH);
digitalWrite(dma_b2_pin, HIGH);
}
if (l > MATRIX_WIDTH - 13){
if (l > MATRIX_WIDTH - 13){ // pull the latch 13 clocks before the end of matrix so that reg2 stars counting to save the value
digitalWrite(dma_lat_pin, HIGH);
} else {
digitalWrite(dma_lat_pin, LOW);
}
digitalWrite(dma_clk_pin, HIGH);
digitalWrite(dma_clk_pin, HIGH); // 1-clock pulse
digitalWrite(dma_clk_pin, LOW);
}
// drop the latch and save data to the REG1 all over the FM6126 chips
digitalWrite(dma_lat_pin, LOW);
digitalWrite(dma_clk_pin, LOW);
}
break;
}
case SHIFT:
default:
break;

68
FM6126A.md Normal file
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@ -0,0 +1,68 @@
## The mystery of control registers for FM6126A chips
Datasheet for this chis chip is in chineese and does not shed a light on what those two control regs are.
An excellent insight could be found here
https://github.com/hzeller/rpi-rgb-led-matrix/issues/746#issuecomment-453860510
So there are two regs - **REG1** and **REG1**,
one could be written with 12 clock pusles (and usually called reg12, dunno why :))
the other one could be written with 13 clock pusles (and usually called reg13, dunno why :))
So I've done some measurmens on power consumption while toggling bits of **REG1** and it looks that it could provide a fine grained brighness control over matrix.
There are 6 bits (6 to 11) giving an increased brighness (compared to all-zeroes) and 4 bits (2-5) giving decreased brighness!!!
So it seems that the most bright (and hungry for power) value is
bool REG1[16] = {0,0,0,0,0, 1,1,1,1,1,1, 0,0,0,0,0}; and not {0,1,1,1,1, 1,1,1,1,1,1, 1,1,1,1,1} as it is usually used.
I'm not sure about bit 1 - it is either not used or I was unable to measure it's influence to brightness/power.
Giving at least 10 bits of hardware brightness control opens pretty nice options for offloading. Should dig into this more deeper.
Here are some of the measurments I've took for 2 64x64 panels filled with white color - reg value and corresponding current drain in amps.
|REG1 |bit value|Current, amps |
|--|--|--|
|REG1| 0111111 00000| >5 amps|
|REG1| 0100010 00000| 3.890 amp|
|REG1| 0100000 00000| 3.885 amp|
|REG1| 0011110 00000| 3.640 amp|
|REG1| 0011100 00000| 3.620 amp|
|REG1| 0011000 00000| 3.240 amp|
|REG1| 0010010 00000| 2.520 amp|
|REG1| 0010001 00000| 2.518 amp|
|REG1| 0010001 10000| 2.493 amp|
|REG1| 0010000 00000| 2.490 amp|
|REG1| 0010000 11110| 2.214 amp|
|REG1| 0001100 00000| 2.120 amp|
|REG1| 0001000 00000| 1.750 amp|
|REG1| 0000100 00000| 1.375 amp|
|REG1| 0000010 00000| 1.000 amp|
|REG1| **0000000 00000**| 0.995 amp|
|REG1| 0000001 11111| 0.700 amp|
|REG1| 0000000 01111| 0.690 amp|
|REG1| 0000000 10000| 0.690 amp|
|REG1| 0000000 11110| 0.686 amp|
/Vortigont/