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Connecting Signals
© National Instruments Corporation
allowing the device to generate data at higher rates because it is not limited
by the PCI bus bandwidth. To enable onboard memory looping:
•
NI-DAQ C interface—In
ND_PATTERN_GENERATION_LOOP_ENABLE
Set_DAQ_Device_Info
•
LabVIEW—Use the DIO Parameter VI to set the Pattern Generation
Loop Enable attribute to ON.
You have the following restrictions when looping from the onboard
memory of the NI 6534:
•
For 8-bit data, the buffer size must be a multiple of 4.
•
For 16-bit data, the buffer size must be an even number.
There are no restrictions for 32-bit data. For 8- or 16-bit data, you may need
to add dummy data to the buffer to make it the correct size.
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 as soon as it is acquired.
Interrupt-driven transfers are slower and take more processing time from
the computer than DMA-driven transfers.
1.
Connect the digital input signals to the I/O connector using the pinout
diagrams, Figure C-1,
and Figure C-2,
68-to-50-Pin Adapter Pin
2.
Connect the ACK pin of the NI 653X to the NI 653X-ready line of the
peripheral device.
3.
Connect the REQ pin of the NI 653X to the peripheral-ready line of the
peripheral device.
Set_DAQ_Device_Info
function.
NI 653X I/O Connector 68-Pin
2-21
Chapter 2
Using Your NI 653X
, set
to
in the
ND_ON
Assignments,
Assignments.
NI 653X User Manual
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