This is a simple USB LCD, based on STM32F103C8T6 "Blue Pill" board and a cheap graphic LCD. ST7565R-based LCDs are supported. GMG12864-06D LCD was tested, for the rest some adjustments might be necessary.
Here is the wiring diagram:
| STM32 pin | LCD Module pin |
|---|---|
| A2 | RST (RSE) |
| A3 | RS |
| A4 | CS |
| A5 | SCL |
| A7 | SI |
The only thing you should care about is the backlight current. There should be a current limiting resistor on the back side of LCD module, please check if it's really there and is not zero-Ohm.
The communication protocol is very simple. SW just sends a raw display content to USB BULK device endpoint 0x01 and then confirms that transmission is done by sending an empty package to the same endpoint. test.py contains an example of the communication. This USB LCD is supported by this lcd4linux fork.
Clone the repository with submodules and build everything
git clone --recurse-submodules https://github.com/Sl-Alex/SlAlexUSBLCD.git
./make_all.shThe result would be two *.bin files, the one with *_BL.bin is for DFU bootloader,
another one can be flashed directly.