From: Liam Girdwood <lrg@slimlogic.co.uk>
To: Richard Zhao <linuxzsc@gmail.com>
Cc: alsa-devel@alsa-project.org
Subject: Re: ASOC: For SND_SOC_DAIFMT_IB_IF what is invert baseed on?
Date: Mon, 27 Oct 2008 13:47:27 +0000 [thread overview]
Message-ID: <1225115247.28382.129.camel@dell-desktop.example.com> (raw)
In-Reply-To: <4e090d470810270624l5587d382o78330f737d709b8a@mail.gmail.com>
On Mon, 2008-10-27 at 21:24 +0800, Richard Zhao wrote:
> > Not quite, the clock is simply inverted compared to it's normal level.
> >
>
> Well, what's the normal level? i2s LRCLK 's normal level is low for
> frame start, but pcm's normal level is high for frame start.
>
> Different chips may have different meaning of "invert", because
> "normal level" is not well defined.
normal == standard.
I2S spec is here :-
http://www.nxp.com/acrobat_download/various/I2SBUS.pdf
and is well defined.
> SND_SOC_DAIFMT_NB_NF is a common
> macro, so it cannot depend on any chip. So, could you please explain
> in details what normal level and invert level of LRCLK/BCLK are in
> i2s, pcm, left/right justified?
>
The wm8750 datasheet shows all this in diagrams :-
http://www.wolfsonmicro.com/uploads/documents/WM8750.pdf
It might be easier if you would send in your code so we can see what you
are trying to accomplish.
Liam
prev parent reply other threads:[~2008-10-27 13:47 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-10-25 16:31 ASOC: For SND_SOC_DAIFMT_IB_IF what is invert baseed on? Richard Zhao
2008-10-26 16:05 ` Liam Girdwood
2008-10-27 3:00 ` Richard Zhao
2008-10-27 10:46 ` Liam Girdwood
2008-10-27 11:26 ` Liam Girdwood
2008-10-27 13:24 ` Richard Zhao
2008-10-27 13:47 ` Liam Girdwood [this message]
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