ADLINK ACL-8454/12 - Manual (Page 38)

30 • Signal Connections & Applications
4.3 Digital I/O Connection
The ACL-8454 provides 16 digital input and 8 digital output channels
through the connector CN1. The digital I/O signals are fully TTL/DTL
compatible.
Digital Output (DO)
GND
Digital Input(DI)
From TTL Devices
To TTL Devices
ACL-8454 Outside Device
Figure 4.1 Digital I/O Connections
4.4 Timer / Counter Connection
The ACL-8454 has four 8254 chips on board. It offers 8 independent 16-bit
programmable down counters and two pairs of cascaded counters. To
implement your applications, you can follow the procedure to design your
applications and connect the signals.
1. Check if the frequencyof the clock source is fixed, if answer is ‘No’
then go to step 7.
2. Calculate the frequency of clock according to your application and
decide the clock source: internal, external, or cascaded. Then
decided which counter is used.
3. If internal clock source is used, configure the CK n jumpers
according the calculation in step 2.
4. If external clock source is used, to generate a clock source outside
the board and check the frequency.
5. If cascaded clock source is used, to configure and program the
cascaded timer to generate the desired clock source.
6. If frequency of the clock is not fixed, only external source can be
used and then connect the external jump wires according your
application.
7. Decide the gate control source: always enable, externally control, or
cascaded controlled.
8. To connect or configure the gate signal of counter/timers.
9. To program the counter/timers using desired mode.