MVS-8100D Hardware Description
2
34
Cognex MVS-8100D and CDC Cameras Hardware Manual
Figure 14 shows the bidirectional parallel I/O circuit for each TTL_BI_
n
line.
Figure 14. Bidirectional parallel I/O circuit
Notes on the parallel I/O circuitry:
•
The minimum allowable Vcc is 4.75 V.
•
If
direction
is high, the circuit is an input; if
direction
is low, an output.
•
In output mode, the 74ABT125 drives the TTL_BI_
n
signal high and low. That is, it
is not an open-collector output.
When a bidirectional line is configured as an output line, the output current for logic high
voltage (VOH) for each TTL line is 32 mA, and for logic low voltage (VOL) is 64 mA.
When a bidirectional line is configured as an input line, it is the responsibility of the
application to drive the circuit both high and low. Do not let the circuit float to signal low.
3
TTL_BI_5
8
TTL_BI_4
13
TTL_BI_3
4
TTL_BI_2
9
TTL_BI_1
14
TTL_BI_9
5
TTL_BI_12
10
TTL_BI_11
15
TTL GND
Pin
Signal Name
Pin
Signal Name
Pin
Signal Name
Table 18. Pinout of parallel I/O connector on MVS-8100D2 and MVS-8100D3
74ABT125
TTL_BI_
n
74LVC126
Direction
Vcc (5V)
200 mA
