>From the top google hit on "uboot set gpio":

http://e2e.ti.com/support/arm/sitara_arm/f/791/t/248181.aspx

...it's even for a TI Sitara processor.

Executive summary:
Use u-boot commands to directly access memory to turn on the GPIO clock
and setup pinmux and gpio values as desired.

And here's the u-boot documentation page on memory commands:
http://www.denx.de/wiki/view/DULG/UBootCmdGroupMemory#Section_5.9.2.6.

On 4/14/2014 10:09 AM, [email protected] wrote:
> Dear Gerald,
> 
> Isn't it possible to set the IO's in the U-boot? 
> before the kernel is started.
> This would be fast enough.
> 
> Regards,
> 
> 
> Maarten
> 
> Op maandag 14 april 2014 16:40:16 UTC+2 schreef Gerald:
>>
>> Read the datasheet for the default state of each pin on power up.
>>
>> http://www.ti.com/product/am3358
>>
>> These cannot be changed. Once the SW is loaded, it can set the pins to 
>> whatever function it supports.
>>
>> Gerald
>>
>>
>>
>> On Mon, Apr 14, 2014 at 9:37 AM, <[email protected] <javascript:>>wrote:
>>
>>> Dear Reader,
>>>
>>> I have a question about the following problem.
>>> On the PCB I designed I use the BBB for setting some pumps and valves.
>>> When the system starts up the first seconds the IO pins are not logic 1 
>>> or 0.
>>> Is it possible to set the GPIO's in U-boot before starting up the kernel 
>>> and how can I do this?
>>>
>>> Thanks,
>>>
>>> Maarten
>>>
>>>  -- 
>>> For more options, visit http://beagleboard.org/discuss
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>>
>>
> 


-- 
Charles Steinkuehler
[email protected]

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