This sample will draw some basic rectangles onto the display. The rectangle colors and positions are chosen so that you can check the orientation of the LCD and correct RGB bit order. The rectangles are drawn in clockwise order, from top left corner: red, green, blue, grey. The shade of grey changes from black through to white. If the grey looks too green or red at any point or the order of the corners is not as described above then the LCD may be endian swapped.
Building and Running
As this is a generic sample it should work with any display supported by Zephyr.
west build -b nrf52840dk_nrf52840 samples/drivers/display -- -DSHIELD=adafruit_2_8_tft_touch_v2
For testing purpose without the need of any hardware, the Native POSIX execution (native_posix) board is also supported and can be built as follows;
west build -b native_posix samples/drivers/display