I/O pin functionality is a function of the processor. Not the board.

Gerald

On Mon, Sep 7, 2015 at 10:05 PM, rattus <[email protected]> wrote:

> On Monday, September 7, 2015 at 6:52:12 PM UTC-6, Graham wrote:
>>
>> Well, by definition, the boot programming pins are going to have the
>> pull-ups / pull-downs, so you know what they are going to be doing, until
>> over-ridden.
>>
>> Most processors start up with the programmable pins as inputs, then move
>> to the configured state.
>>
>
> If it were so... but it seems with such an abundance of modes and pins, a
> number of the pins I am using are in a variety if input, output, hi-Z and
> I/O defaults at powerup, most often with pullup or pull-downs. The good
> news is, I've added enough gating and the additional fast-starting Vdd to
> avoid conflicts. SPI attached peripherals (powered early) all need commands
> shifted in to drive outputs, so that's safe too.
>
> Now for the *next* Beaglebone, innocuous I/Os would be a great feature...
>
> Anything else can be dangerous to the pins.  But, as Charles says, RTFM.
>>
>
>> If you are concerned, use the bus-isolation /transmission-gate  chips,
>> power them early, supply your own pull-ups/pull-downs, and switch the
>> connection on when SYS_RESETn goes high.  Then you are unconditionally
>> safe, and in-control.
>>
>> --- Graham
>>
>
> Thanks,
>
> Mike
>
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-- 
Gerald

[email protected]
http://beagleboard.org/

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