Re: Coldfire MCF5272 - GPIO pin at reset

Am Freitag, den 07.03.2008, 15:46 -0600 schrieb Martin Coria:
> The MCF5272 manual says in the  Overview section corresponding to GPIO
> that “To avoid indeterminate read values and reduce power consumption,
> internal pull-up resistors are active immediately upon reset, and
> remain active until the corresponding port direction registers are
> programmed”.
> 
>  
> 
> Which we understand means that GPIO pins are driven to a known state
> at reset by the pull-up resistors.
>  
> 
> We want to take advantage of this fact (GPIO pin known state at reset)
> but wanted to check with the group to make sure we understand this
> statement correctly and see if anyone has any experience with this.
> 
>  
> 
> Thanks,
> 
>  
> 
> Martin
> 
Hi Martin
Yes, but the value of these pull-ups is not specified. In principle the
pull-ups simply allow you to leave an unused (multiuse) GPIO-pin open
and it will not "flicker" around because of some (capacitively) picked
up noise.
Regards Bob 


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