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IO behavior after reset

Posted: Mon Jul 18, 2016 10:09 am
by raulvalencia
Hi everybody,

I'm working with nucleo STM32F401 board and ChibiOS 16.1.4

I have a problem with the IO's behavior when I start my board or after a reset my IO's output is 1 logic during 210ms (pulse) and I need that it stays in 0 logic but I do not know to do it... a pull down does not works.

in Ref Manual :
During and just after reset, the alternate functions are not active and the I/O ports are
configured in input floating mode.


Thanks in advance,

Raul

Re: IO behavior after reset

Posted: Mon Jul 18, 2016 1:07 pm
by Giovanni
hi,

Pin are programmed in block in board files, the default is input with pull up. If you need them to be programmed differently then you need to create your own custom board files.

This does not explain however what you see DURING the reset.

Giovanni

Re: IO behavior after reset

Posted: Mon Jul 18, 2016 8:12 pm
by rew
It also matters a bit which IO you're talking about. A few IOs will default to a debugging function after reset. (You're probably right that they are supposed to be "floating input" DURING reset).