SYS_CH_SET
set predefined channel
A: channel ID
0 - serial port
1 - OLED, 8 pixels width
2 - OLED, 6 pixels width
SYS_CH_PARAM
define own channel
A: set of parameters
HL, DE, BC: parameters
A=1 (calls)
HL: single char print call
DE: clear screen call
BC: set position call
A=2 (screen size)
D: chars per line
E: lines per screen
A=3 (font definition)
HL: font pointer
B: font width
SYS_CH_CHAR
print one char/send one char to channel
ESC sequences allowed
A: char ascii to print
RST 10h
print/send null-terminated string
string follows RST 10 instruction
RST 10h
.TEXT "HELLO WORLD"
.DB 00h
SYS_CH_SEND
print/send one char, no ESC
A:char/byte to print
SYS_CH_BCD
convert BCD number to ascii and print
A: dual BCD to print
B: options
1 - never print upper nibble
2 - do not print leading zero
4 - print space instead of leading zero
0 - always print leading zero
SYS_CH_HEX
print HEX value
A: value to print in HEX format
ESC codes
16h - set new position to x, y (coordinates follows)
14h - inverse video
15h - normal video
0Ch - clear screen