(No. 70251) 7
JX-S555(J)
Circuit Description
1. IC2 (µPD780021ACWW01)
The µPD780021ACWW01 is a 64-pin, 8-bit single-chip microcomputer with an 8K-byte ROM and 512-byte RAM.
Pin Name
P40/AD0
P41/AD1
P42/AD2
P43/AD3
P44/AD4
P45/AD5
P46/AD6
P47/AD7
P50/A8
P51/A9
P52/A10
P53/A11
P54/A12
P55/A13
P56/A14
P57/A15
Vss
0
V
DD0
P30
P31
Pin No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
Function
Key scan inputs.
Key scan outputs.
Scan signal outputs for LED lighting.
Dubbing lock ON/OFF. H = ON. L = OFF.
Scan signal outputs for LED lighting.
CH1 INHIBIT ON/OFF. H = ON. L = OFF.
Not used.
Not used.
Not used.
Port grounding potential.
Port positive potential.
CH2 INHIBIT ON/OFF. H = ON. L = OFF.
CH3 INHIBIT ON/OFF. H = ON. L = OFF.
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O
—
I
I/O
I/O
I/O
