NOTE: This also appears to be the same protocol used by the X25 and XB323QK NV monitors' RGB LED controllers. Those monitors just have LED strips of different lengths.
Acer appears to have unique (VID, PID) combinations for all their RGB lighting controllers. The XB273U NV's controller has the combination:
| VID | PID |
|---|---|
0x42e |
0xac0c |
- Number of LEDs: 90
- When facing the rear of the monitor, LED index zero corresponds to the LED at the left end of the strip.
The controller enumerates as a USB HID device. It appears to accept OUT reports of different types - some trigger builtin effects while others allow direct control of the RGB LEDs.
At the moment, only the report that allows for direct host LED control has been reverse engineered.
The direct control report has the following structure:
- Report type:
0x2a - Buffer length:
0x175bytes
| Offset (Byte) | Content | Description |
|---|---|---|
| 0 | 0x0c |
magic (command lsb?) |
| 1 | 0x02 |
magic (command msb?) |
| 2 | 0x00 |
magic (padding?) |
| 3 | 90 |
Number of LEDs |
| 4 | 0x0f |
LED strip index |
| [5, 12] | 0x00 |
magic (padding?) |
| [13, 372] | not fixed | RGB data. up to 120 * (R,G,B) byte tuples in range [0, 255]. |
See ctrl_hid_dump for a raw dump of the HID descriptors.
See ctrl_lsusb for lsusb output.
raw_test.py is a simple unoptimized script that demonstrates report
generation.