[Gta04-owner] fm-tuner - was Re: hw routing audio patch removed in 3.7?

Christoph Mair christoph.mair at gmail.com
Sat Jun 8 19:27:07 CEST 2013

On Sat, Jun 8, 2013 at 6:58 PM, Andreas Kemnade <andreas at kemnade.info> wrote:
> ok, lets summarize what i have seen.
> Signals at McBSP1 look fine. I was able to add a sound card to send out
> data to McBSP1. McBSP1 is master. I was never able to get any data from
> McBSP1. Since McBSP1 is master, it should always get data, since it
> generates the clock by itself. When recording data, the clocks are
> present.

The frame sync signals are also ok?

> I asked in linux-omap about that, got one hint, but that did not help
> and also nobody seems to use McBSP1 in master mode.

I used the McBSP1 in master mode to read data from an analog/digital
converter. I did not use the sound API but the corresponding McBSP
functions. I'll  see if I can dig up the code.
A few things I can remember: When enabled, the McBSP starts the
(externally measurable) clocks. To get any useful data you have to
program the frame sync signals. For my application the OMAP generated
the TX-Framesync (FSX) and the ADC generated the RX-FS (FSR), but you
can also set the McBSP to generate both internally. To use this
feature the pinmux has to be correct, IIRC the FSR needs to be muxed
as *input* but it will also output the framesync signals at the same
time. I don't know if the Si4721 requires the FSR or generates its

Hope this helps.

Best regards,

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