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FIR Accelerator usage without interrupt

Question asked by MarcGallo on Feb 25, 2014
Latest reply on Feb 25, 2014 by MarcGallo

How can the FIR accelerator be used without interrupts?

 

In the example code, all FIR accelerator projects use a "dummy" FIR DMA ISR, even when you select "don't generate interrupts" in the expert code generator plugin.

 

Can this be done without interrupts? If so, can you supply sample code that does that?

 

Here is my strategy:

 

Fs=48kHz, buffer size is 16 samples.

SPORT ISR is called when each buffer arrives.

results from previous FIR accelerator are swapped into audio out buffers, while new input samples are copied into proper locations in FIR accelerator input buffer.

FIR accelerator is instructed to start another process just before SPORT ISR returns

by the time another SPORT ISR is generated, the FIR is done.

 

this simple strategy really doesn't need interrupts for the FIR DMA...but when I try to use the expert code generator output without the FIR DMA ISR, even though it's a "dummy" isr, I don't get any processing...

 

what are we missing?

 

marc

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