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

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Chapter 5 Programming
© National Instruments Corporation 5-19 AT-MIO-64F-5 User Manual
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Clear the analog output
circuitry including the DAC
FIFO
Program the update
interval counter
Set the A4RCV bit in
Command Register 2
Set the waveform
generation mode
Service update requests
Internal
update ?
Clear the A4RCV bit in
Command Register 2
Yes
No
Enable updating
Select the update counter
via RTSI programming
Figure 5-7. Cyclic Waveform Programming
Programmed Cycle Waveform Generation
A superset of the waveform functionality exists if DAC data buffer is less than or equal to 2,048
for one channel, or less than or equal 1,024 per DAC for two channels. In these cases, the entire
buffer resides wholly within the DAC FIFO where the waveform circuitry cycles through the
buffer when the end is reached. This removes a large burden on the PC bus for continually
updating data in the DAC FIFO. Also due to the smaller buffer size, the hardware has more