Raspberry Pi with PiTFT - some GPIO weirdness

Adrian Chadd adrian at freebsd.org
Sat Feb 28 16:30:38 UTC 2015


Please file a PR with this information and I'll make sure the ARM GPIO
folk see it.

Thanks!


-a


On 28 February 2015 at 05:24, Milan Obuch <freebsd-arm at dino.sk> wrote:
> On Sat, 28 Feb 2015 19:36:58 +0800
> Erich Dollansky <erichsfreebsdlist at alogt.com> wrote:
>
>> Hi,
>>
>> On Sat, 28 Feb 2015 11:18:52 +0100
>> Milan Obuch <freebsd-arm at dino.sk> wrote:
>>
>> > today I found some time to play a bit with my little display
>> > attached to Rasoberry Pi, and I decided to test buttons connected
>> > to GPIO, as this should work on FreeBSD already. According docs,
>> > buttons are connected to GPIO lines 23, 22, 21 and 18, leftmost
>> > first.
>> >
>> > Using basic 'gpioctl -f /dev/gpioc0 -lv' command I found only first
>> > one, on line 23, reacts. It has value 1 normally and 0 when pressed.
>> >
>> you must setup the pins as inputs first before using them as inputs. I
>> would not rely on any defaults.
>>
>> Erich
>
> According available docs, all GPIO are set to input mode after reset.
> This seems not to be the case, but that's not my point. What was a bit
> of surprise for me was even 'gpioctl -f /dev/gpioc0 -l' tells those
> pins are in input mode ('pin nn<IN>'), it did not work. And fact that
> even after power disconnect the state remains the same is even more
> weird.
>
> Anyway, I accept the necessity for setup, the question is, where should
> these setup instruction go.
>
> Regards,
> Milan
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