Skip site navigation (1)Skip section navigation (2)
Date:      Sun, 20 Dec 2015 11:20:40 -0600
From:      Karl Denninger <karl@denninger.net>
To:        freebsd-arm@freebsd.org
Subject:   Re: Set GPIO at boot on Raspberry Pi
Message-ID:  <5676E368.7080800@denninger.net>
In-Reply-To: <5676DF0F.1060602@fsck.ch>
References:  <5676DF0F.1060602@fsck.ch>

next in thread | previous in thread | raw e-mail | index | archive | help
This is a cryptographically signed message in MIME format.

--------------ms090105090903000300080206
Content-Type: text/plain; charset=windows-1252
Content-Transfer-Encoding: quoted-printable


On 12/20/2015 11:02, Toby wrote:
> Hi all
>
> Is there a way to set GPIOs at boot? I'd like to set GPIO 28 to out and=

> high before usb devices are probed, in order to be able to use my usb
> disk. If I have it plugged in during boot, I can't get it to work. It
> works though if I boot the pi, then plug in the disk and then set the
> pin to high.
>
> Thanks,
> Toby
I've had good luck setting the state FIRST, then the pin config to
desired (in this case, OUT.)

I have this general problem with driving a relay board, in that the
jackwads that designed the board set it up to be active LOW, so if you
set the config first you chatter the outputs, and FreeBSD's GPIO config
rejects "active low" config as a setting.

The pins should come up configured as inputs so the peripheral shouldn't
be upset about that.

--=20
Karl Denninger
karl@denninger.net <mailto:karl@denninger.net>
/The Market Ticker/
/[S/MIME encrypted email preferred]/

--------------ms090105090903000300080206
Content-Type: application/pkcs7-signature; name="smime.p7s"
Content-Transfer-Encoding: base64
Content-Disposition: attachment; filename="smime.p7s"
Content-Description: S/MIME Cryptographic Signature
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--------------ms090105090903000300080206--



Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?5676E368.7080800>