Commodore Amiga A500 Technical Reference Manual 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 ~ t s of AL on Entry:
>
Data Word Length
>
# of stop b ~ t s
>
Parity Enabled / 1
I
>
~ v e ; Parity
>
Baud Rate Bits:
000
-
l l0 Baud
001
-
1 S O 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: D X
=
lndex into device table
AL
=
Character t o transmit
CX
=
Timeout value
BX
=
0,
used as timeout counter
OUTPUT: AH
=
Line Status
RECEIVE A CHAR (AH
=
02H)
INPUT: D X
=
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