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32F413 Port Pin States During Deep Sleep?

JOLSO.11
Associate II

I'm the hardware guy on a 32F413 project where we have a lot of impulse noise nearby on the PCB.  Because of this I've been on a campaign to make certain that all microcontroller I/O pins are equipped with pull-up or pull-down resistors.

The project has reached the stage where our quality assurance folks get cranky whenever I try to add a resistor to this PCB.  So when I find a 32F port pin that is missing a pull up/pull down resistor (as I did this week) it becomes a crisis of meetings and memos.

Remind me to never work again in a medical equipment company.

So I approached our firmware guy and asked him to alter his code to make certain the offending port pin is equipped with either an internal pull-up or a pull-down during his sleep mode,

Firmware guy replies:  "No can do, hardware guy.  The micro is in its deepest sleep state and the port pins flap in the breeze during deep sleep.  You must fix that undefined I/O state with an external resistor. Luv ya, big guy..."

Is this true?  Do all port pins go to tri-state mode during deep sleep?

1 ACCEPTED SOLUTION

Accepted Solutions
AScha.3
Chief II

>The micro is in its deepest sleep state and the port pins flap

Depends on the sleep mode , if its Standby ...then, from ds:

AScha3_0-1720284684601.png

and from rm:

AScha3_1-1720284716481.png

So some pins still working (to wake up cpu) , but all other ... hi Z , off.

So better put a pulldown/-up on every output pin, that would float otherwise.

I do this always on "important" output signals, just because on every start/powerup the cpu is in reset and all (almost all) pins floating anyway. 

(Input pins should anyway have some fixed state, from the circuit the signal is coming from.)

If you feel a post has answered your question, please click "Accept as Solution".

View solution in original post

1 REPLY 1
AScha.3
Chief II

>The micro is in its deepest sleep state and the port pins flap

Depends on the sleep mode , if its Standby ...then, from ds:

AScha3_0-1720284684601.png

and from rm:

AScha3_1-1720284716481.png

So some pins still working (to wake up cpu) , but all other ... hi Z , off.

So better put a pulldown/-up on every output pin, that would float otherwise.

I do this always on "important" output signals, just because on every start/powerup the cpu is in reset and all (almost all) pins floating anyway. 

(Input pins should anyway have some fixed state, from the circuit the signal is coming from.)

If you feel a post has answered your question, please click "Accept as Solution".