[alsa-devel] at91 SoC Modifications

Liam Girdwood lg at opensource.wolfsonmicro.com
Thu Jun 21 23:26:24 CEST 2007

On Thu, 2007-06-21 at 14:10 -0500, Paul Kavan wrote:

> The playback side of everything seems to work well for .raw files. I
> have some that I made with my old ssc polling driver. The sound fine
> using aplay with either the bare bones or the default alsa.conf file.
> However, I cannot use arecord at all. I am not sure why, but something
> is preventing the sync line from working during record. The sync line
> has a .3V,pp square that rides around 3V DC. The frequency is that of
> the bit clock ~256.4K. Now, when I playback a sample, the RF0 and RD0
> look like they should. 
> I have RF0 and TF0 tied together and assume TF0 generates the sync.
> Also, I have TK0 and RK0 tied together and assume TK0 generates the
> clock. Could this be the problem.

Best not to assume here, check the Atmel datasheet wrt SSC clocking.

> Oh...and playback with PCM A (DSP_A) works fine, but no recording
> still. I get the same type of signal on RF0 as before with PCM A fmt.
> Does anyone have a sense if this is a ssc configuration problem or an
> alsa problem? 

It's probably not an alsa problem as playback works.  If your SSC
register settings for capture look correct then I'd check the hardware


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