Clear Pending Write

[Brian C]

Greetings.

Background

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In my application I have two devices on the CANBUS: a controller and a USB-8473.  The controller communicates using a query / repsonse protocol: my application sends a query or command frame; the device responds.  The protocol requires several query / response exchanges to get the controller into a particular mode.  If a failure occurs, the program sends a reset frame to the controller and starts over from the beginning.

Observations

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From what I can tell, when a frame is passed to the NICAN API to be written to the CANBUS, the API continues indefinately trying to write the frame until it succeeds.

Question

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To start over, the program needs to clear the pending frame.  To clear the pending frame, I did this...

  ncAction( fHandle, NC_OP_RESET, 0 )

Is this the best choice?  Is there another method to flush the pending frame (flush the write queue)?

Thank you,

Brian

[Burban · Accepted solution]

Brian,

The current way you are doing this flush, ncAction with the Reset opcode, is recommended.  Is there some reason you are looking to use a different function?

Regards,

Ben

[Brian C]

Ben,

Thank you for the reply.

I'm looking for something different because ncAction / Reset clears everything including the baud rate and the error counts.

Brian

[Burban]

ncAction with the Reset opcode is going to be your only option for clearing the Write Queue of your USB CAN interface.  I will make the suggestion to our R&D department that in some situations it would be useful to have something like an ncAction / Flush instead of the full Reset.

Regards,

Ben

[Brian C]

Thank you and I hope you have a good day,

Brian