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DDS implementation with KL25Z

Question asked by Franco Bucafusco Bucafusco on Oct 15, 2015
Latest reply on Oct 15, 2015 by Alice_Yang

Hi! I have been trying to implement a DDS with the DMA peripheral of a KL25Z.

 

The basic Idea is to transfer one period of my signal without CPU intervention to a single memory location (DAC output register), periodically. THe sample time is commanded by the PIT tick.

 

I could do it by reloading the DMA configuration in each period, within the DMA IRQ handler but I have the problem of the IRQ handler processing latency, so I was thinking a way of workarround that behavior.

 

Then I tried to use a second DMA channel, linked with the first one, to transfer the configuration for the 1rst channel when the signal period expired. But I could make it work. Is that possible to do?

 

The idea is to have all the DDS process without CPU intervention.

 

Any tip will be apreciated.

 

I have found many examples using the eDMA module (from another kinetis cpus) but s few for the DMA module of the KL25z one.

 

Thanks!

Franco

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