Choosing Dma Or Interrupt Transfers; Connecting Signals; Creating A Program - National Instruments 653 Series User Manual

Connecting Signals

Creating a Program

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Choosing DMA or Interrupt Transfers

When using DMA (default), the NI 6534 transfers data in 32-byte blocks,
and the NI 6533 transfers data in 4 byte blocks. Therefore, at any time
during a continuous operation, there may be up to 31 bytes (or 3 bytes for
the NI 6533) of data in an internal FIFO. You can use interrupt-driven
transfers if you need to retrieve data immediately as it is acquired.
Interrupt-driven transfers are slower and take more processing time from
the computer than DMA-driven transfers.
Connect digital input signals to the I/O connector using the pinout
diagrams, Figure C-1,
Figure C-2, 68-to-50-Pin Adapter Pin
If you are using external start and/or stop triggers, connect to the
appropriate pins—start trigger (ACK or STARTTRIG) and/or stop trigger
(STOPTRIG).
Using the following flowcharts as a guide, create a program to perform
change detection. Figure 2-20 and Figure 2-21 display flowcharts for C
programming using NI-DAQ, and Figure 2-22 shows a LabVIEW
programming flowchart.
The boxes represent function names for the appropriate software, and the
diamonds represent decision points.
NI 653X I/O Connector 68-Pin
Assignments.
2-33
Chapter 2 Using Your NI 653X
Assignments, or
NI 653X User Manual