2009-01-27 13:23:49     DAC Driver suggestions

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2009-01-27 13:23:49     DAC Driver suggestions

David Welch (UNITED STATES)

Message: 68425   

 

I'm a little surprised there is not more app notes published or "hardened" drivers for the BF-537 Stamp to connect to a high performance DAC. It seems like a natural and rather pragmatic peripheral for a DSP board.

 

To get started, I have both a CS4398 and AKM4396 eval boards with I2S inputs. Both of these chips DAC chips are hardware controlled and their settings are fixed by board jumpers. No SW configuration needed.

 

Once I get these chips working, I'd like to integrate the AD1955, one of my all time favorite DAC chips btw!

 

 

 

Question: Could someone guide me to any known documentation or drivers for streaming PCM data over I2S?

 

Thank you,

 

-David

 

 

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2009-01-27 16:29:45     Re: DAC Driver suggestions

Mike Frysinger (UNITED STATES)

Message: 68436   

 

audio codecs get their own specific driver so that they fit into the greater audio subsystem in Linux, so no generic i2s driver exists.

 

basically the codec driver goes in linux-2.6.x/sound/soc/codecs/ and then the method for connecting a codec to the rest of the system (i.e. the SPORT) is implemented in a codec-independent way in linux-2.6.x/soc/blackfin/bf5xx-i2s.c.

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2009-01-27 16:32:13     Re: DAC Driver suggestions

David Welch (UNITED STATES)

Message: 68437   

 

Thanks Mike, This was a big help. -David

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2009-01-27 17:13:23     Re: DAC Driver suggestions

David Welch (UNITED STATES)

Message: 68443   

 

In researching the Linux audio architecture, nearly all documentation relates to sound cards in standard PC environments.

 

Could someone suggest a resource for learning more about the audio architecture of the uClinux environment for embedded devices like the BF537 Stamp? I also noticed the 2008R1.5 release supports OSS. Are other sound architectures ported to uClinux?

 

A website, book, or anything someone more knowledgeable could suggest as a good reference.

 

Thank you!

 

-David

 

 

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2009-01-27 17:19:14     Re: DAC Driver suggestions

Mike Frysinger (UNITED STATES)

Message: 68444   

 

OSS is dead and shouldnt be looked at in any way

 

on embedded systems you should focus on the ALSA SoC Layer.  the places i referred to earlier are part of that.  but this is just the lowest part of ALSA ... everything on top of it behaves the same for everyone (i.e. Linux on your desktop).

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