STM 32F4 PA0/WKUP pin and TIM5 - what are the gotchas?

[peter-h]

I have been reading the RM and various stuff online about this, and wonder what the issues are with PA0 if the 32F4 is not used in any low power modes.

On my board, PA0 is set up to be an input with a pulldown, but it otherwise unused because we could not work out the full extent of the limitations. I would like to use it with TIM5 (CH1, via AF2) which is handy because it is a 32-bit timer.

CH1 can be an input or an output so you can use it for PWM etc.

[DavidAlfa]

I don't get it?
It's very much like a normal GPIO, with the exception that it can be used to wake up the stm32 while in sleep mode.
If configured for that, the pin won't be disabled when the stm32 goes into deep sleep state.
In running state there would be no limitations at all? Have you actually tried to use it as TIM5 CH1?

[peter-h]

I have not tried it because it could be working "by luck"

Also, the timers are complex so something might not be working for multiple reasons.

But from what you say it is simple. The data sheet talks a lot about PA0 and the onboard voltage regulator, etc. and it doesn't sound totally simple.

[DavidAlfa]

What F4?

[peter-h]

Sorry - STM 32F417

[Siwastaja]

I don't see any issue.

I understand your concern, I myself feel like validating every normal thing I do on STM32 because always there is a gotcha somewhere, or outright silicon bug, documented or non-documented.

But you have to draw the line somewhere, you need to assume that the alternative functions listed in the pin mapping section of the datasheet means those alternative functions actually work.

[peter-h]

Thank you

The data could directly state that PA0 is a GPIO pin unless low power modes are used, but it doesn't say that.