UBI EasyCoder 601 XP – Service Manual Ed. 1
116
Chapter 16 Interfaces
16.3 Parallel
Communication Port
"centronics:",
cont'd.
1-971603-28 Centronics pcb.; Components
1-971603-28 Centronics pcb.; Schematics
Modifications:
Although IEEE 1284 specifies a SELECT
IN signal to be set low by the host during
communication, many hosts do not sup-
port this signal. Therefore, we have modi-
fied the Centronics interface board so
the SELECT IN signal is no longer re-
quired.
C1
C2
C3
C4
IC1
IC2
IC3
L1
L2
L3
L4
L5
L6
L7
L8
L9
L10
L11
L12
L13
L14
L15
L16
L17
P1
P2
R1
R2
R3
RN1
L1-L17
1-971603-02-P01
P1
P1
VCC
IOCS1E
IORD
IOWR
IOD7
IOD6
IOD5
IOD4
IOD3
IOD2
IOD1
IOD0
A3
A2
SELIN
ERROR
ACK
CWOE
SELECT
PERR
AF
CROE
CWSTR
BUSY
CRSTR
STROBE
INIT
RESET
SYSCLK
STROBE
ACK
BUSY
PERR
SELECT
AF
INIT
ERROR
INT3741
Gnd
G
A1
A2
A3
A4
Y1
Y2
Y3
Y4
VCC
OC
CLK
1D
2D
3D
4D
5D
6D
7D
8D
1Q
2Q
3Q
4Q
5Q
6Q
7Q
8Q
Gnd
G
A1
A2
A3
A4
Y1
Y2
Y3
Y4
VCC
Gnd
Gnd
CGND
CGND
Gnd
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
12
14
16
18
8
6
4
2
1
4
3 2
1
1
11
2
3
4
5
6
7
8
9
19
18
17
16
15
14
13
12
2
3
4
5
6
7
8
9
1
3
5
7
9
17
15
13
11
19
5
6
9
8
11
10
13
12
‹
‹
‹
P1
P2
L17
L12
L11
L10
L16
L15
L14
L13
L9
L1
L2
L3
L4
L8
L7
L6
L5
R1
74AC244
IC2A
74HCT14
IC3B
74HCT14
IC3A
74HCT574
IC1
RN1
74AC244
IC2B
R2
R3
C3
C1
C2
C4
74HCT04
IC3C
74HCT04
IC3D
74HCT04
IC3E
74HCT04
IC3F
DSTROBE
SELECT
ERROR
AF
PE
BUSY
ACK
D7
D6
D5
D4
D3
D2
D1
D0
INIT