Adafruit Feather M4 Express issues with ST7789

[dexter4000]

I have tried to implement the LovyanGFX library in a sketch to test a ST7789 display, but no luck.
I can't get it to work in either spi_mode. I can get it to display with AdafruitGFX fine.

Here is the code

#include <LovyanGFX.hpp>

class LGFX : public lgfx::LGFX_Device
{
  lgfx::Panel_ST7789 _panel_instance;
  lgfx::Bus_SPI _bus_instance;

public:
  LGFX(void)
  {
    {
      auto cfg = _bus_instance.config();
      cfg.spi_mode = 2;           
      cfg.freq_write = 40000000;  
      cfg.freq_read  = 16000000;  
      cfg.pin_sclk = 24;          
      cfg.pin_mosi = 23;          
      cfg.pin_miso = -1;          
      cfg.pin_dc   = 10;          

      _bus_instance.config(cfg);
      _panel_instance.setBus(&_bus_instance);
    }

    {
     
      auto cfg = _panel_instance.config();
      cfg.pin_cs     = 5;         
      cfg.pin_rst    = 9;         
      cfg.pin_busy   = -1;        

      cfg.memory_width  = 240;    // Driver IC memory width
      cfg.memory_height = 240;    // Driver IC memory height
      cfg.panel_width   = 240;    // Actual display width
      cfg.panel_height  = 240;    // Actual display height
      cfg.offset_x      = 0;      // Panel X offset
      cfg.offset_y      = 0;      // Panel Y offset
      cfg.offset_rotation = 2;    // Rotation offset 2 (180 degrees for MRD display)
      cfg.dummy_read_pixel = 16;  // Dummy read pixel count
      cfg.dummy_read_bits  = 1;   // Dummy read bits
      cfg.readable    = false;    // true if data can be read
      cfg.invert      = true;     // true if inverted colors (MRD displays need this)
      cfg.rgb_order   = false;    // true if RGB order (false = BGR)
      cfg.dlen_16bit  = false;    // true for 16-bit data length
      cfg.bus_shared  = false;    // true if bus is shared

      _panel_instance.config(cfg);
    }

    setPanel(&_panel_instance);
  }
};

LGFX display;

void setup(void)
{
  Serial.begin(115200);
  delay(2000); // Wait for Serial Monitor
  Serial.println("LovyanGFX with MRD 1.54 ST7789 Display Test Starting...");

  // Initialize backlight pin manually for SAMD51
  pinMode(6, OUTPUT);
  digitalWrite(6, HIGH);  // Turn on backlight
  Serial.println("Backlight turned on");

  // Initialize display
  display.init();
  Serial.println("Display initialized!");
  
  // Add manual initialization sequence that we know works
  display.startWrite();
  display.writeCommand(0x01); // Software reset
  delay(150);
  display.writeCommand(0x11); // Sleep out
  delay(500);
  display.writeCommand(0x3A); // Pixel format
  display.writeData(0x55);    // 16-bit color
  display.writeCommand(0x36); // Memory access control
  display.writeData(0x00);
  display.writeCommand(0x21); // Inversion on
  display.writeCommand(0x13); // Normal display on
  display.writeCommand(0x29); // Display on
  display.endWrite();
  delay(100);
  
 // Test with a simple fill to verify it's working
  display.fillScreen(TFT_RED);
  delay(1000);
  display.fillScreen(TFT_BLACK);
  
  Serial.println("Starting test sequence...");
  delay(1000);
}

void loop(void)
{
  // Test 1: Fill screen with colors
  Serial.println("Test 1: Color fills");
  display.fillScreen(TFT_RED);
  delay(500);
  display.fillScreen(TFT_GREEN);
  delay(500);
  display.fillScreen(TFT_BLUE);
  delay(500);
  display.fillScreen(TFT_WHITE);
  delay(500);
  display.fillScreen(TFT_BLACK);
  delay(500);

  // Test 2: Draw rectangles
  Serial.println("Test 2: Rectangles");
  display.fillScreen(TFT_BLACK);
  display.drawRect(10, 10, 100, 100, TFT_WHITE);
  display.fillRect(30, 30, 60, 60, TFT_YELLOW);
  delay(1000);

  // Test 3: Draw circles
  Serial.println("Test 3: Circles");
  display.fillScreen(TFT_BLACK);
  display.drawCircle(120, 120, 50, TFT_CYAN);
  display.fillCircle(120, 120, 30, TFT_MAGENTA);
  delay(1000);

  // Test 4: Draw lines
  Serial.println("Test 4: Lines");
  display.fillScreen(TFT_BLACK);
  for (int i = 0; i < display.width(); i += 10) {
    display.drawLine(0, 0, i, display.height() - 1, TFT_GREEN);
  }
  for (int i = 0; i < display.height(); i += 10) {
    display.drawLine(0, 0, display.width() - 1, i, TFT_BLUE);
  }
  delay(1000);

  // Test 5: Text rendering
  Serial.println("Test 5: Text");
  display.fillScreen(TFT_BLACK);
  display.setTextColor(TFT_WHITE, TFT_BLACK);
  display.setCursor(10, 10);
  display.setTextSize(1);
  display.println("MRD 1.54 Display");
  display.setTextSize(2);
  display.println("LovyanGFX");
  display.setTextSize(3);
  display.println("Works!");
  delay(2000);

  // Test 6: Gradient
  Serial.println("Test 6: Gradient");
  for (int y = 0; y < display.height(); y++) {
    uint8_t hue = (y * 255) / display.height();
    uint32_t color = display.color565(hue, 255, 255);
    display.drawFastHLine(0, y, display.width(), color);
  }
  delay(2000);

  // Test 7: Random pixels animation
  Serial.println("Test 7: Animation");
  display.fillScreen(TFT_BLACK);
  for (int i = 0; i < 100; i++) {
    int x = random(display.width());
    int y = random(display.height());
    int r = random(5, 20);
    uint16_t color = display.color565(random(256), random(256), random(256));
    display.fillCircle(x, y, r, color);
    delay(20);
  }
  delay(1000);

  // Test 8: Brightness control (manual PWM on SAMD51)
  Serial.println("Test 8: Brightness fade");
  display.fillScreen(TFT_WHITE);
  
  // Note: Manual brightness control using analogWrite on pin 6
  // The Feather M4 Express supports PWM on pin 6
  for (int brightness = 255; brightness >= 0; brightness -= 5) {
    analogWrite(6, brightness);
    delay(20);
  }
  for (int brightness = 0; brightness <= 255; brightness += 5) {
    analogWrite(6, brightness);
    delay(20);
  }
  delay(500);

  // Test 9: Rotation test
  Serial.println("Test 9: Rotation");
  for (int rotation = 0; rotation < 4; rotation++) {
    display.setRotation((rotation + 2) % 4); // Add 2 to account for base 180° rotation
    display.fillScreen(TFT_BLACK);
    display.setTextColor(TFT_WHITE);
    display.setTextSize(2);
    display.setCursor(10, 10);
    display.print("Rotation: ");
    display.println(rotation);
    display.print("Width: ");
    display.println(display.width());
    display.print("Height: ");
    display.println(display.height());
    delay(1500);
  }
  display.setRotation(2); // Reset to upright orientation

  Serial.println("All tests completed! Restarting...\n");
  delay(2000);
}