ADLINK Technology PCI-8124, User Manual, Page: 44 / 85

Operation Theory 35
perform continuous triggering. Each FIFO has 1023 random com-
paring data space. If users have more random data than 1023, try
to polling FIFO empty status or wait interrupt event and refill reset
random data.
4.2.5 Timer function
There are 4 timers on PCI-8124. The timer is started by TTL input
and the timer can be set to counters to simulate encoder inputs. It
can also output to trigger pins directly. The timer is designed by a
down-counter. Users must set a counter value into timer for down
counting. Once the timer counter reaches zero, the timer will out-
put a pulse to trigger pin or increase encoder counter by 1. The
down counting speed is 400ns and the maximum counter value is
14-bit.