Help Needed: STM32L0 Microcontroller Sleep Mode Issue with NRF24 and SIM808 Modules

[AlexPap]

Hi Developers,

I have an STM32L0 microcontroller connected to an NRF24 module via SPI and a SIM808 module via UART. The system is designed to remain in stop mode until an interrupt is triggered by the NRF24 module. Upon interrupt, the microcontroller wakes up, sends data to a database via the SIM808 module, and then returns to sleep mode.

However, after the initial wake-up, the microcontroller fails to wake up again, even if messages are sent to the NRF24 module. Strangely, if I comment out the execution of the SIM808 module, the system works properly.

I've checked the interrupt handling, power management settings, UART communication, and hardware connections, but I'm still stuck. Any ideas on what might be causing this issue?

[RomainR.]

Hello @AlexPap 

Do you mean that the STM32L0 is capable of wake-up up only once from an EXTI interrupt on the NRF24 module's GPIO IRQ (initial wake-up?) Then, after goes into STOP mode aagin, it doesn't wake up on the next interrupt?
How do you manage this interrupt, and as you indicate that by commenting the SIM808 execution solves your problem, isn't there a GPIO or interrupt resource conflict in your application?

Best regards,
Romain