Performing software reset while maintaining certain GPIOs in tact

[yuri CH]

Hi 🙂

I am using the STM32F7 to develop a system which has some mechanical parts including a motor.

Sometimes there is a need to reset the system using the SW reset, just before that i want to lock the motor in place. Therefore i need to keep the voltage and the state of his GPIOs the same during the reset itself.

i want to know whether there is a way to perform the SW reset while keeping my GPIO situation and voltage the same?

could find anything regarding this issue in the reference manual.

thanks a lot in advance!

Yuri.

[waclawek.jan]

> i want to know whether there is a way to perform the SW reset while keeping my GPIO situation and voltage the same?

No, any reset sets all GPIO registers to their reset value, i.e in case of 'F7 as inputs.

You can either try to mimic the SW reset by setting all relevant registers to their reset value (most of this can be achieved through the reset registers for individual modules in RCC), or if you want to achieve this functionality with a genuine reset, you have to build some external circuitry which would then behave as you wish.

JW

[yuri CH]

thanks ...

[Ozone]

That's more a stategical decision from ARM, all Cortex M core base devices behave that way.

You could try to achieve your desired behavior via pull-up resistors, or latched buffers.