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>
index | next in thread | previous in thread | raw e-mail 

[-- Attachment #1 --]

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.

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

[-- Attachment #2 --]
0	*H
010
	`He0	*H
_0[0C)0
	*H
010	UUS10UFlorida10U	Niceville10U
Cuda Systems LLC10UCuda Systems LLC CA1"0 	*H
	Cuda Systems LLC CA0
150421022159Z
200419022159Z0Z10	UUS10UFlorida10U
Cuda Systems LLC10UKarl Denninger (OCSP)0"0
	*H
0
X@vkY
Tq/vE]5#֯MX\8LJ/V?5Da+
sJc*/r{ȼnS+w")ąZ^DtdCOZ ~7Q '@a#ijc۴oZdB&!Ӝ-<	?HN5y
5}F|ef゘"Vلio74zn">a1qWuɖbFeGE&3(KhixG3!#e_XƬϜ/,$+;4y'Bz<qT9_?rRUpn5
Jn&Rx/p Jyel*pN8/#9u/YPEC)TY>~/˘N[vyiDKˉ,^" ?$T8v&K%z8C @?K{9f`+@,|Mbia007++0)0'+0http://cudasystems.net:88880	U00	`HB0U0,	`HB
OpenSSL Generated Certificate0U-h\Ff Y0U#0$q}ݽʒm50U0karl@denninger.net0
	*H
Owbabɺx&Uk[(Oj!%pMQ0I!#QH}.>~2&D}<wm_>V6v]f>=Nn+8;q wfΰ/RLyUG#b}n!Dր_up|_ǰc/%ۥ
nN8:d;-UJd/m1~VނיnN I˾$tF1&}|?q?\đXԑ&\4V<lKۮ3%Am_(q-(cAeGX)f}-˥6cv~Kg8m~v;|9:-iAPқ6ېn-.)<[$KJtt/L4ᖣ^Cmu4vb{+BG$M0c\[MR|0FԸP&78"4p#}DZ9;V9#>Sw"[UP7100010	UUS10UFlorida10U	Niceville10U
Cuda Systems LLC10UCuda Systems LLC CA1"0 	*H
	Cuda Systems LLC CA)0
	`HeM0	*H
	1	*H
0	*H
	1
151220172040Z0O	*H
	1B@[]C,X<ˆdͯOvٲR(8{r򣠼y0u⨳R`r;0l	*H
	1_0]0	`He*0	`He0
*H
0*H
0
*H
@0+0
*H
(0	+710010	UUS10UFlorida10U	Niceville10U
Cuda Systems LLC10UCuda Systems LLC CA1"0 	*H
	Cuda Systems LLC CA)0*H
	1010	UUS10UFlorida10U	Niceville10U
Cuda Systems LLC10UCuda Systems LLC CA1"0 	*H
	Cuda Systems LLC CA)0
	*H
)XL	tkL:萐Lvcfɲt[Ɵ0E:
7dCwOwk"ők͑~nWzb5BrKnpbnԵi
F
r$#	}*t"3Gp3F6}MP\axL5cr1D@[_p/7XTS-(R	=JecS~4څc`kHG 9)epƮL@htAĮ7G0@(fȈA\~kfMbHz+St9KP)=Q?A>̣ԧXZ/6uƔܭ݉%_%d$/K5璲imJ2,oǁtKA8V
QO"P6ԣs
6CF3N–c^zѵ-x+Q;
help

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