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PXA255 - WinCE GPIO status at sleep recovery

Edwin Decoene
Note: This was originally posted on 1st August 2012 at http://forums.arm.com

Hi all,
I'm on to make some changes on a old project (WinCE420), where I want to keep a few output GPIO's in a high state during SleepMode. Seems to work well (the PGSR0 register keeps the selected GPIO's high), but after resuming the GPIO's are set back to low, though in the actual GPIO registers the pins are still high. Any idea, or what register I should check on to avoid this, or is this intended behavior ?
The manual says: "Leaving Sleep Mode causes a Sleep Mode reset. Unlike other resets, Sleep Mode resets do not change the state of the pins." What am I doing wrong ?

All help highly appreciated. Thanks a lot in advance !
  • Note: This was originally posted on 2nd August 2012 at http://forums.arm.com

    Hi all,

    Sorry to bother you all with this, but the issue is solved. Looks like a newer version of the power mgr was resetting the GPIO register behind my back when entering the suspend mode. So the processor restored after the resume the GPIO with the value in the GPLR register, which was low in the mean time.

    Cheers

    Hi all,
    I'm on to make some changes on a old project (WinCE420), where I want to keep a few output GPIO's in a high state during SleepMode. Seems to work well (the PGSR0 register keeps the selected GPIO's high), but after resuming the GPIO's are set back to low, though in the actual GPIO registers the pins are still high. Any idea, or what register I should check on to avoid this, or is this intended behavior ?
    The manual says: "Leaving Sleep Mode causes a Sleep Mode reset. Unlike other resets, Sleep Mode resets do not change the state of the pins." What am I doing wrong ?

    All help highly appreciated. Thanks a lot in advance !
  • Note: This was originally posted on 13th August 2012 at http://forums.arm.com

    Thanks a lot for coming back to post the reply!
    This way the thread can be useful to others...
    Cheers,
    Alban