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GPIO state during flash/reset

Tim Woolliscroft

Hi,

I am new to ARM and the KEIl tools so please forgive if Ive missed something basic here.

I have inherited a project using a ADUC7026 and am trying to achieve a tidy up of the project, the issue I am struggling with is:

I have several devices attached to GPIO which should not be turned "on" until the system is fully up and several checks have been passed.
At power on (and during flash) the GPIO on these pins seem to be configured as inputs with the internal pullup enabled? Unfortunately the PCB is configured with logic level NFETS which turn on easily.

I've looked though the start up code and configuration wizard and cant find anything to help me there (can't say i'm an assembler guru though).

Is there anything I can do?

Thanks

Tim

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  • 0

    The state of the hardware at power-up or reset is beyond the control of the software - because the software is not running at that point!

    The power-up/reset states of the pins should be described in the chip datasheet.

    This is a hardware question which you need to direct to the chip manufacturer - nothing to do with Keil, and not specifically to do with ARM.

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  • 0

    The state of the hardware at power-up or reset is beyond the control of the software - because the software is not running at that point!

    The power-up/reset states of the pins should be described in the chip datasheet.

    This is a hardware question which you need to direct to the chip manufacturer - nothing to do with Keil, and not specifically to do with ARM.

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  • 0 in reply to Andy Neil

    I have inherited a project from one of those that do not read datasheets before designing.

    I know of no uC that start up with port pins low. Were I stupid enough to not read datasheets before designing I would design based on pins being high during reset.

    Anyhow to get somewhere with what you have (NOT to release the board) you MAY get by with some pulldown resistors (use as high a values as you can).

    Erik