Is there a way to pause PXI6541 once it has started generation?

[davefisher]

Hello,

Is there a way to pause PXI-6541 once it has started data generation by using the PFI

lines? I want to use a PXI 6541 to send test data to a downstream compression chip which,

depending on setup, might delay in processing the input data. I would like to route

the half full flag of the compression chip  back to the PXI- 6541  to pause the PXI6541

generating data if data starts to back up in the input buffer of the comression chip (using

a PFI line). I would also route another  PFI line to the valid data input of the compression

chip to denote vaild data.

I am using niHSDIO C calls to implement the generation but I can not find any examples

 of doing this.

NIHSDIO_ATTR_PAUSE_TRIGGER_TYPE  is defined in niHSDIO.h but I am not sure

what this is used for.

Any help would be appreciated,

Thanks

David.y.fisher@nasa.gov

[Ryan_M]

David,

the 654x can certainly use implement a Pause trigger in the way you described.  The use case you described is a perfect usecase.  The Pause trigger (for generation) is a request, so routing an "almost" full flag works great to hold off a generation.  Detailed information on the Pause trigger can be found in the help file ("START/Programs/National Instruments/NI-HSDIO/Documentation"):

Devices::NI 654x::Generation::Dynamic Generation::Dynamic Generation Triggers and Events
("Pause Trigger")

Additionally, there is a "Data Valid" event which may be exported.  Information on this event can be found in the help under the same topic ("Data Active Event").  Note that Data Valid will deassert when the operation is paused.

Please let us know if you have any questions on these topics


Message Edited by Ryan M on 06-02-2008 10:32 AM