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Date:      Wed, 8 Oct 2014 14:43:28 -0300
From:      Luiz Otavio O Souza <lists.br@gmail.com>
To:        Luiz Otavio O Souza <lists.br@gmail.com>, ticso@cicely.de, AN <andy@neu.net>, "freebsd-arm@freebsd.org" <freebsd-arm@freebsd.org>
Subject:   Re: FreeBSD on BeagleBone Black
Message-ID:  <CAB=2f8x6LiC0ZXre4jjmbH=UyA-pqukfYnU_ikji3vBRM_LkiQ@mail.gmail.com>
In-Reply-To: <20141008053451.GV1852@funkthat.com>
References:  <alpine.BSF.2.11.1410071517050.940@mail.neu.net> <20141008010436.GA12125@cicely7.cicely.de> <20141008030621.GU1852@funkthat.com> <CAB=2f8zzre5%2BoPFr8G6gOefS6-dghgTMHfMnEMWNP-pyNVUZsA@mail.gmail.com> <20141008053451.GV1852@funkthat.com>

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On 8 October 2014 02:34, John-Mark Gurney wrote:
> Luiz Otavio O Souza wrote this message on Wed, Oct 08, 2014 at 01:07 -0300:
>
[...]
>> I also see some GPIO pins on schematics (like GPIO0_19 and GPIO1_27 on
>> page 3) which may need to be set for the HDMI support and i did not
>> check the gonzo's code to verify if they are properly set.
>
> Yeh, GPIO1_27 is the one that enables the clock to the HDMI chip and
> when I was looking over his patch, I didn't see anything for enabling
> it...  This is mentioned in the SRM...
>
> Looks like GPIO0_19 isn't necessary as that is the clock for CEC,
> and we don't need that till later (say use the TV remote as an input
> device)...

Well, you'll find that the BBB documentation is... confusing...

GPIO1_27 enable the 24.576MHz clock used on McASP (multichannel audio
serial port). This clock is connected back to GPIO3_21 (McASP clock
input). It can be disabled to allow the use of GPIO3_21, to reduce the
power drain or to allow an external McASP clock.

GPIO0_19 enable the 12MHz clock which is actually used by TDA19988.

I hope it make sense.

/me looking forward for the HDMI support (and then, audio ?!? :)

Luiz



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