Set character
Writes a character on the screen.
A1 [in,1u]
A2 [in,1u]
A3 [in,1u(char)]
A4 [in,1b]
A5 [out,1b]
BX [in,4u]
BY [in,4u]
CX [in,4u(XRGB)]
CY [in,4u(XRGB)]
This message allows you to set a character in the screen in the text mode.