Hello professionals 
I would like to build my own dot matrix display.
I got the idea from Adafruit. It is a 16 x 24 LED dot matrix display with a Holtec HT1632 controller and an ESP32 to drive it.
When building the board, I had to rotate each of the 6 8x8 Dot Matrix modules 90 degrees anti-clockwise to make it easier to route through the legs.
I was aware that I would have to rotate the displays 90 degrees anti-clockwise again later via software.
I use the Adafruit HT1632 library because it is obvious.
The library assumes that column 0 and row 0 (top left) control the first LED. The last LED of the first row is then at 0;23 (top right).
The first LED of the last row is at 15;0 (bottom left) and the last at 15;23 (bottom right). So there are exactly 384 LEDs that can be controlled.
The board is now assembled and works perfectly from a technical point of view.
However, because each of the 6 x 8x8 LED matrix is mechanically rotated 90 degrees anti-clockwise, I now have to correct this via software.
I have now given up trying to solve the problem with simple For next loops because I am a beginner. After eight hours I was completely exhausted.
To make progress, I have built two arrays where I store the corrected coordinates. However, this costs me 768 bytes of ram! Not a good solution.
Now I can set every single LED in Adafruit style via Set Pixel.
But only from my sketch.
But if I now want to use the Adafruit GFX Library library referenced from the Adafruit_HT1632 library, this is not possible because they do everything internally.
So I have no way of transferring my corrected coordinates to the Adafruit GFX Library library.
I now have two questions:
Is it possible to do it smarter with rotating the 8x8 LED dot matrix displays without using 768 bytes?
Does anyone see a way to pass my corrected coordinates to the Adafruit_HT1632 library without changing the library?
If I had to change the library, I would be lost because I've never done anything like this before.
Thanks for trying to help me.
Greetings Bienchen
#include "Adafruit_HT1632.h"
#define HT_DATA 14
#define HT_WR 0
#define HT_CS 4
//#define HT_CS2 5
// use this line for single matrix
Adafruit_HT1632LEDMatrix matrix = Adafruit_HT1632LEDMatrix(HT_DATA, HT_WR, HT_CS);
// use this line for two matrices!
//Adafruit_HT1632LEDMatrix matrix = Adafruit_HT1632LEDMatrix(HT_DATA, HT_WR, HT_CS, HT_CS2);
// Y = Row and X = Columm
uint8_t X_ARRAY[384];
uint8_t Y_ARRAY[384];
void setup() {
Serial.begin(9600);
pinMode(27, OUTPUT);
digitalWrite(27, LOW); // sets OE to disabled
delay(1000);
digitalWrite(27, HIGH); // sets OE to enabled
delay(1000);
matrix.begin(ADA_HT1632_COMMON_16NMOS);
matrix.fillScreen();
delay(500);
matrix.clearScreen();
matrix.setTextWrap(false);
matrix.setRotation(0);
//matrix.clearScreen();
matrix.setBrightness(1);
matrix.setCursor(0, 0);
Fill_Array();
}
void loop() {
uint8_t X_Work =0;
uint8_t Y_Work =0;
for (uint ADA_I=0;ADA_I < 384;ADA_I++){
X_Work = X_ARRAY[ADA_I];
Y_Work = Y_ARRAY[ADA_I];
//Serial.print(" ADA Count = "); Serial.print(ADA_I);Serial.print(": Y Work = "); Serial.print(Y_Work);Serial.print(" X Work = "); Serial.print(X_Work);Serial.println();
//matrix.setPixel(X_Work, Y_Work);
//matrix.writeScreen();
//delay (1000);
// if (ADA_I == 383) {
// matrix.clearScreen();
// }
}
}
void Fill_Array() {
uint Counter = 0;
uint8_t x=7;
uint8_t X_modulo=0;
uint8_t y_modulo=0;
for (int8_t l=0; l<16; l++) {
for (uint8_t i=1; i<4; i++) {
switch (i){
case 1:
x=7;
break;
case 2:
x=15;
break;
case 3:
x=23;
break;
}
if (l < 8 ) {
x=x-l ;
} else if (l > 8 ) {
x=x-(l-8 );
}
for (uint8_t y=0; y<8; y++) {
X_modulo= Counter % 24;
y_modulo= Counter / 24;
if (l > 7){
X_ARRAY[Counter] = x;
Y_ARRAY[Counter] = y + 8;
matrix.setPixel(x, y + 8);
Serial.print(" LED Position = "); Serial.print(Counter);Serial.print(" ADAKORDS : X = ");Serial.print(X_modulo); Serial.print(" Y = ");Serial.print(y_modulo);Serial.print(" / MY = ");Serial.print(" X = "); Serial.print(x); Serial.print(" Y = ");
Serial.print(y + 8);
Serial.println();
} else{
X_ARRAY[Counter] = x;
Y_ARRAY[Counter] = y;
matrix.setPixel(x, y);
Serial.print(" LED Position = "); Serial.print(Counter);Serial.print(" ADAKORDS : X = ");Serial.print(X_modulo); Serial.print(" Y = ");Serial.print(y_modulo);Serial.print(" / MY = ");Serial.print(" X = "); Serial.print(x); Serial.print(" Y = ");
Serial.print(y);
Serial.println();
}
Counter++;
matrix.writeScreen();
delay (500);
}
}
}
matrix.clearScreen();
Serial.print("ARRAY written");Serial.println();
}
