Digital i/o ports…… 17, Digital i/o ports caution – Measurement Computing Digital488/80A User Manual
Page 23
Digital I/O Ports
CAUTION
When the HVCX1 option is used, the I/O lines are hardware configured as either
inputs or outputs. The hardware and software configurations for the input and output
ports must agree. The Digital488/80A unit is protected from configuration conflict,
but the I/O lines will not respond properly.
The Digital488/80A has two DB-50 connectors -- Channel 0 and Channel 1 -- each of which provides 40
data lines programmable in groups of 8 bits as either input or output ports. The following figure illustrates
one of the digital I/O DB-50 connectors as viewed from the rear panel of the Digital488/80A. Both
Channel 0 and Channel 1 DB-50 connectors are identical.
DB-50 Con
or
nect
Pin
Description
Comment
Pin
Description
Comment
1
Port 1 Bit 1
I/O, Port 1 LSB
26
Port 4 Bit 2
Input/Output
2
Port 1 Bit 2
Input/Output
27
Port 4 Bit 3
Input/Output
3
Port 1 Bit 3
Input/Output
28
Port 4 Bit 4
Input/Output
4
Port 1 Bit 4
Input/Output
29
Port 4 Bit 5
Input/Output
5
Port 1 Bit 5
Input/Output
30
Port 4 Bit 6
Input/Output
6
Port 1 Bit 6
Input/Output
31
Port 4 Bit 7
Input/Output
7
Port 1 Bit 7
Input/Output
32
Port 4 Bit 8
I/O, Port 4 MSB
8
Port 1 Bit 8
I/O, Port 1 MSB
33
Port 5 Bit 1
I/O, Port 5 LSB
9
Port 2 Bit 1
I/O, Port 2 LSB
34
Port 5 Bit 2
Input/Output
10
Port 2 Bit 2
Input/Output
35
Port 5 Bit 3
Input/Output
11
Port 2 Bit 3
Input/Output
36
Port 5 Bit 4
Input/Output
12
Port 2 Bit 4
Input/Output
37
Port 5 Bit 5
Input/Output
13
Port 2 Bit 5
Input/Output
38
Port 5 Bit 6
Input/Output
14
Port 2 Bit 6
Input/Output
39
Port 5 Bit 7
Input/Output
15
Port 2 Bit 7
Input/Output
40
Port 5 Bit 8
I/O, Port 5 MSB
16
Port 2 Bit 8
I/O, Port 2 MSB
41
Clear
Output only
17
Port 3 Bit 1
I/O, Port 3 LSB
42
Data Strobe
Output only
18
Port 3 Bit 2
Input/Output
43
Trigger
Output only
19
Port 3 Bit 3
Input/Output
44
Inhibit
Output only
20
Port 3 Bit 4
Input/Output
45
Service Input
Input only
21
Port 3 Bit 5
Input/Output
46
External Data Ready
Input only
22
Port 3 Bit 6
Input/Output
47
(Not Used)
(Not Used)
23
Port 3 Bit 7
Input/Output
48
HVCX1 Flyback
Flyback
24
Port 3 Bit 8
I/O, Port 3 MSB
49
+5 V
50 mA maximum load
25
Port 4 Bit 1
I/O, Port 4 LSB
50
I/O Common
Ground
Digital488/80A User’s Manual
11-08-02
Digital488/80A Setup 17