STM8S003 firmware for the [I²C to HD44780 adapter](https://git.cuvoodoo.info/kingkevin/board/src/branch/i2c_hd44780).

I²C commands (first byte).

simplified commands:

- 0x0 INIT: initialize LCD, as 2-line, 5x8 dots, no blinking or cursor
- 0x1 LINE1: write to line 1, followed by ASCII text
- 0x2 LINE2: write to line 2, followed by ASCII text
- 0x3 DISPLAY_ON: turn display on
- 0x4 DISPLAY_OFF: turn display off
- 0x5 BRIGHTNESS: set backlight brightness, followed by 0-255 value

raw instructions, directly mapping to HD44780, followed by instruction byte or data bytes if applicable:

- 0x6 CLEAR_DISPLAY
- 0x7 RETURN_HOME
- 0x8 ENTRY_MODE_SET
- 0x9 DISPLAY
- 0xa CURSOR_DISPLAY_SHIFT
- 0xb FUNCTION_SET
- 0xc CGRAM_ADDR
- 0xd DDRAM_ADDR
- 0xe DATA