How to Turn ON the STM32 with button?

[DIvan.1]

Hello!

I have a question about power supply and ON/OFF capabilities of microcontroller.

Normally, When power supply is turned ON, the microcontroller Start executing the program.

In my case I want that after Power supply is turn ON, the microcontroller have power but not executing the program code. With powerON button I will start the program (like it is in the computer).

In short word. I want to turn ON the microcontroller with the button, like PC.

Is there any elegant solution for the problem written above?

All the best,

Domen

[srikanth]

Hello Dlvan

At stage of board power on keep the reset pin to low by using on/off switch. When you want to run the code just make the reset pin high by using on/off switch.

[Tesla DeLorean]

Like it enters Standby and you Wake it?​

[DIvan.1]

Yes, something like this.

[DIvan.1]

In "int main(void)" function i write:

 __HAL_PWR_CLEAR_FLAG(PWR_FLAG_WU);
 
 HAL_PWR_EnableWakeUpPin(PWR_WAKEUP_PIN5);
 
HAL_PWR_EnterSTANDBYMode();

 But after I press the button on Power wakeup pin5, the microcontroller don't go to main program (while loop).

Any idea?

Thank you a lot.

[Paul1]

On powerup you may need to wait till the input signal is stable.

So before the EnableWake, do a loop that waits till the PIN has been in non-wake state for several samples.

Do you have any debounce on the switch input? A capacitor may take time to ramp up/down depending on resistor size.

Write some code to sample to read the input to an array many times at powerup (array[1000] and then put breakpoint and look at how many cycles it takes for pin to stabilize. If just using a delay then wait double that time to be safe (temperature and component aging variations)

(The world of digital - isn't always very digital)

Paul