Commodore Computers 1581 - 8520 A Register Map; Register Access and Control

1581 SERVICE MANUAL
REGISTER MAP
D0-D7
DATA BASE BUFFERS!
SP<
CNT <
FLAG
IRQ
SP
SERIAL
PORT
PRA
DORA
PA
BUFFERS
»PA0-PA7
PB0-PB7
A A A A A ATI
S3
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
RS2
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
RS1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
R/W 02
RSO
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
CS RS3
REG
0
1
2
3
4
5
6
7
8
9
A
B
C
D
E
F
RS2 RSI RSO
PRA
PRB
DDRA
DDRB
TALO
TAHI
TBLO
TB HI
SDR
ICR
CRA
CRB
RES
Peripheral Data Reg. A
Peripheral Data Reg. B
Data Direction Reg. A
Data Direction Reg. B
Timer A Low Register
Timer A High Register
Timer B Low Register
Timer B High Register
Event LSB
Event 8-15
Event MSB
No Connect
Serial Data Register
Interrupt Control Register
Control Register A
Control Register B
8