Display isn't lighting

Official Hardware Mega GIGA Display Shield
1

Can someone tell me why the Giga display does not light up in blue or any other color?

The screen is just black.

#include "Arduino_GigaDisplay_GFX.h"

GigaDisplay_GFX display;

#define WHITE 0xFFFF
#define BLUE 0x001F

uint16_t fg = WHITE, bg = BLUE;

void setup() {
  Serial.begin(115200);
  delay(600);
  display.begin();
  delay(100);
  display.fillScreen(bg);
}

void loop() {}
2

I can think of lots of reasons it does not work but without knowing how it was wired I do not have a clue. Post an annotated schematic showing exactly how it is wired. Show all connections, power, ground, power sources and any other hardware that may be connected. Post links to technical information on the hardware items such as the display.

3

It is plugged into a giga R1 and that's it. No accessories, just the USB-c programming connector.

4

Hi @PickyBiker. When you are using the fillScreen function by itself, you must call endWrite() afterwards before it will affect the screen:

  display.fillScreen(bg);
  display.endWrite();

Not absolutely required, since it is currently empty, but it would be a good idea to also call startWrite() before in case the library developers eventually add some code to that function:

  display.startWrite();
  display.fillScreen(bg);
  display.endWrite();

The confusing thing is that, although this is required when using the Arduino_GigaDisplay_GFX library's native functions (drawFastHLine, drawFastVLine, drawPixel, fillScreen) by themselves, the library also inherits many functions from the Adafruit GFX Library (e.g., drawCircle, drawLine, drawRect, fillCircle, fillRect, print) and those functions contain startWrite() and endWrite() calls. For example:

So when you are using the functions from Adafruit GFX Library alone, or following a Arduino_GigaDisplay_GFX library native function, the endWrite() call is not required.

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