Hi,
I am using a c6655 DSP and one of the UPP channel is configured as receive mode.
After the UPP DMA Channel Descriptor is programmed, before the DMA starts, is there any way to re-program the descriptor without doing a soft reset?
GanZ
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Hi,
I am using a c6655 DSP and one of the UPP channel is configured as receive mode.
After the UPP DMA Channel Descriptor is programmed, before the DMA starts, is there any way to re-program the descriptor without doing a soft reset?
GanZ
After the UPP DMA Channel Descriptor is programmed, before the DMA starts, is there any way to re-program the descriptor without doing a soft reset?
Hi Ganz,
There’s a PEND bit in each of the DMA status registers that determines when it’s safe to write the descriptor registers, see below snip from the user’s guide. So my quick answer is, as long as PEND is 0, you can write the registers. The complication here is, when exactly is PEND set and cleared by the uPP IP? The documentation is vague on this point and so somebody from the product group would have to answer that. Have you tried it? What was the result?
Mark
Hi GanZ,
The short answer is no. Once you have initiated a DMA transfer, you either have to wait for it to complete or you have the perform a software reset to the DMA controller which will terminate both the transfers. Once the PEND bit is set, you can preload the DMA parameters for the next transfer but there is no way of overwriting the parameters for the current transfer.
Regards,
Bill