Chapter 5: Programming
Manual Number: 00650-004-5
Page 5-5
Base + 1 Read:
Read Digital Input Byte
Any read to this address clears the IRQ status flag.
7
B
6
B
5
B
4
B
3
B
2
B
1
B
0
B
3
P
I
G
O
C
/
2
P
I
1
P
I
G
I
R
T
/
0
P
I
3
P
O
2
P
O
1
P
O
0
P
O
OP0:
Input bit OP0, if EN0 is high.
OP1:
Input bit OP1, if EN1 is high.
OP2:
Input bit OP2, if EN2 is high.
OP3:
Input bit OP3, if EN3 is high.
IP0/TRIG:
Input bit, Optional ADC start input (TRIG 0) if ADC1 true at base + 0.
IP1:
Input bit.
IP2/ C0G:
Input bit, Shared with Counter #0 enable gate (C0G).
IP3:
Input bit.
40-Pin IDC (8255)
Base + 10 Read/Write:
Parallel Peripheral Interface 8255 Port A
7
B
6
B
5
B
4
B
3
B
2
B
1
B
0
B
7
A
P
6
A
P
5
A
P
4
A
P
3
A
P
2
A
P
1
A
P
0
A
P
Eight bits of digital input/output. Data written to the port may be readback from the same address.
Base + 11 Read/Write:
Parallel Peripheral Interface 8255 Port B - Same format as above.
Base + 12 Read/Write:
Parallel Peripheral Interface 8255 Port C - Same format as above.
Base + 13 Write:
Parallel Peripheral Interface 8255 Command Byte
7
B
6
B
5
B
4
B
3
B
2
B
1
B
0
B
te
S
e
d
o
M
1
A
e
d
o
M
0
A
e
d
o
M
A
tr
o
P
i
H
C
tr
o
P
B
e
d
o
M
B
tr
o
P
o
L
C
tr
o
P