LED ring - MEM_TYPE_LED12

This memory is mapped to the color/brightness of the LEDs on the LED-ring and supports both read and write operations.

The color/brightness is set using the RGB565 format (2 bytes) and the LEDs are mapped after each other. The number of LEDs is defined by the CONFIG_DECK_LEDRING_NBR_LEDS kbuild flag (12 by default) and the last LED will be mapped to address (CONFIG_DECK_LEDRING_NBR_LEDS - 1) * 2.

0 color (RGB565) 0
2 color (RGB565) 1
4 color (RGB565) 2
color (RGB565)
(CONFIG_DECK_LEDRING_NBR_LEDS - 1) * 2 color (RGB565) CONFIG_DECK_LEDRING_NBR_LEDS - 1

RGB565

Red, green and blue are encoded using 5, 6 and 5 bits, adding up to a total of 16 bits (2 bytes).

The encoded values can be converted to 8 bit values (RGB565 to RGB888) like this:

R8 = (R5 * 527 + 23) >> 6;
G8 = (G6 * 259 + 33) >> 6;
B8 = (B5 * 527 + 23) >> 6;


and the other way around, RGB888 to RGB565:

R5 = ((R8 << 6) - 23) / 527;
G5 = ((G8 << 6) - 33) / 259;
B5 = ((B8 << 6) - 23) / 527;