AIC3204 Buffering

Steve Sienk

I've been reading through the AIC3204 documentation and haven't seen anything related to a buffer for DAC transmit values.

Here's what I want to do:

Receive a window of samples, maybe 50ms in length.

Use the C5505 to do some processing on that data as a whole. (I expect this to take less than 50ms, but more than a few sampling periods)

Throw the processed data back out there to the AIC.

Repeat.

It would be nice if after I processed the data I could throw it into a buffer and let the AIC do the rest of the work of outputting values as needed instead of waiting for my code to send it a new value. Does the AIC, or maybe even the C5505, have anything to support this?

Assuming no, then would the next best way be to implement my own buffer and use an interrupt handler to send the next value?

Any insight or suggestions would be much appreciated.

Thanks,

Steve

over 15 years ago

0 Steve Sienk over 15 years ago

Prodigy 30 points

I've been looking through the FFT Filter Demo and its been quite helpful.

So basically I should use I2S and a DMA ISR to do this buffering scheme.

0 Mark M over 15 years ago in reply to Steve Sienk

TI__Mastermind 30140 points

Good point, Steve.

The Audio Filter Demo (http://code.google.com/p/c5505-ezdsp/) also uses the DMA to read and write blocks of samples between internal memory and the AIC3204 Codec.

This would be a great starting point for your project. All you need to do is remove the call to the FIR filter, and replace it with your own signal processing code.

-Mark

0 James McVay over 13 years ago in reply to Mark M

Prodigy 130 points

Hey Mark,

I'm trying to achieve a similar thing - however when I run the Audio Filter Demo, I get the correct output from the right Channel but just a horn-like noise from the left channel. However I'm using the C5515ezdsp Demo on a c5515 board, not the c5505 board. Any help would be appreciated.

Cheers

James

0 Steve Sienk over 13 years ago in reply to James McVay

Prodigy 30 points

It's been a while since I've done anything with this, but I seem to recall a difference between the C5505 and the C5515 in terms of the number of channels it supports...

0 James McVay over 13 years ago in reply to Steve Sienk

Prodigy 130 points

Indeed there is a difference, however the code I'm downloading is design for the c5515 board and I'm using it on a c5515 board so I don't understand why it wouldn't work.... right channel is fine, left channel just sounds like a horn.

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AIC3204 Buffering