Programming instructions

Chapter 4 516 Devices and DAQCard-500/700 Devices
© National Instruments Corporation 4-5 DAQ Hardware Overview Guide
connector. The inverted OUT1 signal is also available on the DAQCard-700
I/O connector.
516 Devices and DAQCard-500 Counter/Timers
The 516 devices and DAQCard-500 contain an onboard MSM82C54
Programmable Interval Timer chip that has three independent 16-bit
counter/timers. NI-DAQ uses the three counter/timers from the 82C54
as follows:
• Counter 0 is used for data acquisition operations.
• Counter 1 is available for counting/timing operations.
• Counter 2 is available for counting/timing operations.
Figure 4-2 shows the connections of the MSM82C54 Counter/Timer
signals to the 516 devices and DAQCard-500 I/O connector.
Figure 4-2.
516 Devices and DAQCard-500 Counter/Timer Signal Connections
The counter has a clock input, a gate input, and an output labeled CLK,
GATE, and OUT, respectively. The clock pin for counters 1 and 2 and the
output pins are available on the device I/O connector. The gate pin for
counter 2 is also available on the I/O connector.
I/O Connector
1 MHz
Source
OUT2
CLK2
GATE2
OUT0
GATE0
CLK0
OUT1
CLK1
GATE1
MSM82C54
Counter/Timer