I'm developing on a custom board with STM32F429. I need to use stop mode for power consumption. We have some external interrupt (e.g. interrupt from accelerometer) we use to wakeup from stop mode.
Wake up is working fine, but the problem is that exiting from stop mode, HSI oscillator is automatically used. I need to reconfigure the PLL prior to executing the interrupt handler that woke up the MCU. I enter stop mode in my idle task as soon as it's possible.
My first solution was to enter stop mode with global interrupt disabled, in order to reconfigure PLL in idle task and then restoring global interrupt and execute the interrupt handler that woke up the MCU. But it's not working: MCU remains in stop mode no matter what.
I used this apporach in the past using a Kinetis MCU (cortex M4) from NXP and it was working fine.
Am I missing something?