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PSoC™ 5, 3 & 1

Anonymous
Not applicable

Hi at all,

I'm trying to terminate a DMA transfer between RAM->VDAC using "trq" pin.

I guess I'm not understanding the timing of "trq" signal with respect to "drq".

In the DMA component datasheet is reported:

"...This signal is only used when the channel is trying to transfer data. A positive edge on this line is ignored at other times..."

I've tried to apply the rising edge of "trq" when "drq" is low or high (changing the delay whit respect to its rising edge) but without success.

I've tried connecting "trq" to a PWM components (sync'ed to another PWM driving "drq") or connecting it to an external pulse generator.

In both cases the transfer is not affected by "trq" signal.

I can only terminate the transfer calling an interrupt routine in which I call the function...

CyDmaChSetRequest(   DMA_Chan, CY_DMA_CPU_TERM_TD);

The interrupt routine is called by PWM or ext pulse generator.

any idea how to make it work properly?

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1 Solution
Bob_Marlowe
Expert II

The trq input is meant to terminate (abandon) a running DMA transfer. Can it be that you need to use the drq input instead which will start a DMA transfer. The transfer will stop automatically when the td chain ends.

Bob

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2 Replies
Bob_Marlowe
Expert II

The trq input is meant to terminate (abandon) a running DMA transfer. Can it be that you need to use the drq input instead which will start a DMA transfer. The transfer will stop automatically when the td chain ends.

Bob

View solution in original post

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EvPa_264126
Valued Contributor II

yes, The "trq" signal will  be able to complete transmission only when transmission is active.

Check out this example

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