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SSC I2S On the SAM7...Does Anyone Have An Example of Code That Works?

Started by ac7zl February 23, 2006
AT91SAM7...nifty chip... but I have to admit to considerable
frustration trying to get this thing to do what I want.

Basically, I have the AT91SAM7S-EK board attached by ribbon cable to a
vectorboard on which I've placed one of TI's TLV320AI23B codecs. The
larger goal is to use the SSC controller in the Sam7 to talk to the
codec. I intend to sample low freq audio and generate low-freq test
signals at an 8khz sample rate. Conceptually, this should be easy to
do, right?  

The trouble is, I can't seem to get the SSC functions to work right.
Early on, I was able to generate appropriate clock and framing
signals,  but generating the correct data is another matter entirely. 
(Yes...all the appropriate jumpers on the EV board have been opened.)

After a few weeks of trying, I came upon application note
6020A-ATARM-11/03 "Connecting the Atmel SSC to an I2S Bus." It
doesn't
apply directly to the AT91SAM7, it references Defines and an interrupt
handler I can't find, and it appears to have some syntax errors, but
all said, I was able to extract enough from it to get I2S
working...sort of. It still isn't right.

I've given up on the codec for now, simply monitoring raw clock,
frame, and data signals with a scope. They're there, but not right,
and I can't seem to get them right.

I contacted Atmel for some help, and an "applications engineer" sent
me some sample code...utter crap, actually. It was incomplete, it
didn't compile, it contained comments that had nothing to do with the
code it referenced, and it did nothing to shed light on this problem. 

I have searched Atmel-related discussion groups on the web, and
Googled 'till the cows come home, and the best I can seem to do is
find numerous examples of other people running into the same kinds of
problems that I have.

This leads me to reiterate a question I saw posted by another
individual a year ago---namely, has anyone successfully used the SSC
functions to transfer I2S to a codec? If so, would you care to share
what seems to be a secret to getting I2S traffic out of the SAM7?

Pete
	
Hello,
I have also just started to use the scc and are a bit daunted by your experience given i have only a few days to get it working.  If you manage to get it working or know of any application examples I could sure use them:)
Thanks,regards
Greg

ac7zl <a...@yahoo.com> wrote:
AT91SAM7...nifty chip... but I have to admit to considerable
frustration trying to get this thing to do what I want.

Basically, I have the AT91SAM7S-EK board attached by ribbon cable to a
vectorboard on which I've placed one of TI's TLV320AI23B codecs. The
larger goal is to use the SSC controller in the Sam7 to talk to the
codec. I intend to sample low freq audio and generate low-freq test
signals at an 8khz sample rate. Conceptually, this should be easy to
do, right? 

The trouble is, I can't seem to get the SSC functions to work right.
Early on, I was able to generate appropriate clock and framing
signals,  but generating the correct data is another matter entirely.
(Yes...all the appropriate jumpers on the EV board have been opened.)

After a few weeks of trying, I came upon application note
6020A-ATARM-11/03 "Connecting the Atmel SSC to an I2S Bus." It doesn't
apply directly to the AT91SAM7, it references Defines and an interrupt
handler I can't find, and it appears to have some syntax errors, but
all said, I was able to extract enough from it to get I2S
working...sort of. It still isn't right.

I've given up on the codec for now, simply monitoring raw clock,
frame, and data signals with a scope. They're there, but not right,
and I can't seem to get them right.

I contacted Atmel for some help, and an "applications engineer" sent
me some sample code...utter crap, actually. It was incomplete, it
didn't compile, it contained comments that had nothing to do with the
code it referenced, and it did nothing to shed light on this problem.

I have searched Atmel-related discussion groups on the web, and
Googled 'till the cows come home, and the best I can seem to do is
find numerous examples of other people running into the same kinds of
problems that I have.

This leads me to reiterate a question I saw posted by another
individual a year ago---namely, has anyone successfully used the SSC
functions to transfer I2S to a codec? If so, would you care to share
what seems to be a secret to getting I2S traffic out of the SAM7?

Pete



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