National Instruments AT-MIO-64F-5, User Manual

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Chapter 5 Programming
© National Instruments Corporation 5-25 AT-MIO-64F-5 User Manual
6. Write (FFF0 + n ) to the Am9513A Command Register to decrement Counter n .
7. Write the following value to the Am9513A Command Register to arm Counter n .
FF21 Ð Arm Counter 1
FF22 Ð Arm Counter 2
FF30 Ð Arm Counter 5
After you complete this programming sequence, Counter n is configured to count the DAC
buffer retransmit signal from SOURCE3 as soon as the load/arm counter command is written.
Programming the Waveform Cycle Interval Counter
To program the cycle-interval Counter for a pulsed cyclic waveform generation mode, use the
following programming sequence. All writes are 16-bit operations. All values given are
hexadecimal.
1. Write FF02 to the Am9513A Command Register to select the Counter 2 Mode Register.
2. Write the mode value to the Am9513A Data Register to store the Counter 2 mode value.
Am9513A counter mode information can be found in Appendix E, AMD Am9513A Data
Sheet .
C225 Ð Selects 5 MHz clock (from SOURCE2 pin)
CB25 Ð Selects 1 MHz clock
CC25 Ð Selects 100 kHz clock
CD25 Ð Selects 10 kHz clock
CE25 Ð Selects 1 kHz clock
CF25 Ð Selects 100 Hz clock
C525 Ð Selects signal at SOURCE5 input as clock (counts the rising edge of the signal,
6 MHz maximum)
3. Write FF0A to the Am9513A Command Register to select the Counter 2 Load Register.
4. Write the desired cycle interval plus one to the Am9513A Data Register to store the
Counter 2 load value.
5. Write FF42 to the Am9513A Command Register to load Counter 2.
6. Write FFF2 to the Am9513A Command Register to decrement Counter 2.
7. Write FF22 to the Am9513A Command Register to arm Counter 2.
After you complete this programming sequence, Counter 2 is configured to count the desired
interval after each rising edge on GATE2 is encountered. The terminal count active low edge
will restart the waveform generation process.