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> Gpios States For Low Consumption
angelo
Posted: December 14, 2016 02:39 pm
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Hi,
i was wondering, when a cpu/mcu enters low consumption sleep mode, what could be the best pin configuration before sleep ? I am setting pins to hi-z. Maybe "input" is good too ?

Thanks
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Sch3mat1c
Posted: December 15, 2016 01:31 am
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Undefined pin states may float into the linear range where current consumption can be higher.

If the IO banks are physically powered down, this won't matter, but I don't know that that's something they ever do.

If you don't want to set a hard pin state, you can use soft pull-up or pull-down states, or external resistors. Whatever sets a well-defined voltage. smile.gif

Tim


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angelo
Posted: December 15, 2016 10:55 am
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Hi tim,

thanks,
no. in my case, gpio stages are not powered off, seems they can still keep the pre-set mode / level in power down mode.

Yes, quite all of the power control GPIOS control mosfets P gates (used as switch), and have external pullups, so setting them hi-z should work fine.

Best regards,
Angelo
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David Stephenson
Posted: December 19, 2016 07:25 pm
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I've found doing sleep power-downs the only way you can be sure is by actually measuring the current and checking against the datasheet.
I generally find there is something I've fogot to disable which is dragging current.
That said I never leave pins as input, but there again I never use pull-ups (except for internal ones) so it may work.
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