Intermec EasyCoder 501 – Service Manual Ed. 7
20
Chapter 2 Front and Keyboard
2.6 Keyboard Interface Board;
Circuit Diagram
Keyboard Interface Board 1-040701-26; Circuit Diagram
C4
C1
C2
IC1
+5V
20
GND
19
PA0
16
ROW0
4
C3
VDISP
18
PA1
15
ROW1
3
ECLK
17
PA2
14
ROW2
2
RESET
35
RESET
16
PA3
R8
13
ROW3
1
RD
5
RD
15
PA4
12
ROW4
40
WR
36
WR
14
PA5
11
ROW5
39
CS
6
CS8255
13
PA6
10
ROW6
38
A1
8
GND
12
PA7
9
ROW7
37
A0
9
GND
11
8
COL0
PB0 18
A6
10
7
COL1
PB1 19
A5
9
6
COL2
PB2
AD0
20
34
DB0
8
5
COL3
PB3
AD1
21
33
DB1
7
4
COL4
PB4
AD2
22
32
DB2
6
3
COL5
PB5
AD3
23
31
DB3
5
2
COL6
PB6
AD4
24
30
DB4
4
1
SHIFT
PB7
AD5
25
29
DB5
3
P3
AD6
A5
74HC04
28
DB6
2
PC0 14
AD7
27
DB7
1
2
3
4
5
6
7
8
9
10
PC1 15
1
P1
12
13
PC2 16
IC2F
PC3
74HC04
17
1
RN1
74HC04
PC4
READY
13
1
PC5
6
5
ERROR
12
1
+5V
10
11
PC6
LED1
LED2
LED3
IC2C
RS
11
IC2E
PC7
74HC04
RW
10
74HC04
82C55
POWER
ERROR
READY
1
4
3
1
8
9
R3
R1
IC2B
IC2D
74HC04
1
2
1
R2
IC2A
14
DB7
13
DB6
12
DB5
11
DB4
10
DB3
9
DB2
8
DB1
7
DB0
3
VDISP
6
ECLK
4
RS
2
3
4
5
6
7
8
9
10
5
RW
R6
R5
R4
2
1
1
RN2
2
P2
R7
1
P4
+5V
+5V
+5V