Parallel Port Interface Circuit - Panasonic JS-170FR Series Service Manual

2.1.5.3

Parallel port interface circuit

The IT8673F is used as a parallel port control.
The parallel port of the IT8673F has a both-way function. When controlled by software, the data signals of the PD7-PD0 become
both-way signals.
The output signals (SLIN, INIT, AFD, STB) for parallel port control are pulled up with 4.7kΩ of open drain output. However, since
they are connected to the power supply terminal through diodes, Device 74LS07 is inserted at an external open collector buffer.
I/O address and interrupt of the parallel port are set up by the software.
IT8673F
PD7
PD6
PD5
PD4
PD3
PD2
PD1
PD0
SLIN
INIT
AFD
STB
ERR
S LCT
BUSY
PE
ACK
105
106
107
108
109
110
111
112
+5V
4.7K
LS07
113
114
116
117
115
100
102
101
103
47K
22K
22K
4.7K
22K
47K
M A 1 5 2 W A
2-20
9
D 7
L
8
D 6
L
7
L
D 5
6
L D 4
5
D 3
L
4
D 2
L
3
L D1
2
L D 0
17
L S L I N #
16
I N I T #
L
14
A F D #
L
1
S T B #
L
15
L E R R #
13
L S L C T #
11
L B U S Y
12
L P E
10
L A C K #
18
G N D
19
20
21
22
23
24
25