Commodore Amiga A500 - Page 132

EM DSR ENTRY POINT
INITIALIZE COMM PORT (AH = OOH)
VIA SIW INT 14H
INPUT: DX = Modem Control Register port
AL = Baud Rate and UART control parameters
BH
= 0, upper bits of baud rate index
OUTPUT: AH
= Line Status
AL = Modem Status
Serial Port Control bits in
AL Register
B~ts of AL on Entry:
> Data Word Length
> # of stop b~ts
> Parity Enabled
/ 1 I > ~ve; Parity
> Baud Rate Bits:
000 - l l0 Baud
001 - 1 SO Baud
010 - 300 Baud
01 1 - 600 Baud
100 - 1200 Baud
101 - 2400 Baud
l l0 - 4800 Baud
I I I - 9600 Baud
TRANSMlT A CHAR (AH = 0 1 H)
INPUT: DX
= lndex into device table
AL = Character to transmit
CX
= Timeout value
BX = 0, used as timeout counter
OUTPUT: AH
= Line Status
RECEIVE A CHAR (AH = 02H)
INPUT: DX = lndex into device table
CX
= Timeout value
BX = 0, used as timeout counter
OUTPUT: AH
= Line Status (error bits only. = 0 if OK)
AL = Received Character