Rt fpga dma timeout not waiting

Question

Hello
I have a Target to Host DMA between. The read function sits in a while loop with a 2000ms timeout. Upon timeout it loops round and recalls the read function. On the second, and subsequent calls, it does not wait for the timeout time. I assume that this is because it was already itemed out. The error is wired to a shift register.
Does the timeout result in an error on the error line?
Is there a way to clear the timeout?
If i change it to an indefinite wait, is there a way to force the read to wake up?
Thanks
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Answer 1

jonnnnnnn wrote:
Hello
I have a Target to Host DMA between. The read function sits in a while loop with a 2000ms timeout. Upon timeout it loops round and recalls the read function. On the second, and subsequent calls, it does not wait for the timeout time. I assume that this is because it was already itemed out. The error is wired to a shift register.
Does the timeout result in an error on the error line?
Is there a way to clear the timeout?
If i change it to an indefinite wait, is there a way to force the read to wake up?
Thanks
Does the timeout result in an error on the error line? Yes, errro -54000 if memory serves correctly. Did you try highlighting execution to see this...
Is there a way to clear the timeout? Don't wire -1, I got burned by this. The DMA actually polls in the background (I think but I never verified) so a negative timeout can slam your processor. You can maybe try interrupts, although I didn't use this method I just threw a not-too-long timeout on there and cleared the error if it was -54000
If i change it to an indefinite wait, is there a way to force the read to wake up? The read will only return when data is there, unless you have a timeout.
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