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STM32G0 wake up by timer external trigger

VeryLatte
Associate II

Hi.

I have a board with STM32G0 that I want to wake up from STOP mode via external signals. And so I used 16 interrupts from GPIO and they work correctly. However, I need one more external input for waking up. Specifically, I have a PA15 pin that has an external pull-up, and the signal that is supposed to wake up pulls this pin to GND. PA15 has AF: TIM2_CH1 and TIM2_ETR. I tried to use ETR, but I don't have the option to select the edge and I don't know why CubeIDE sets this pin as push-pull. Generally, I tried several modes/configs and none of them wakes up the processor, or even jumps to the interrupt from TIM2. Can you suggest something? Example? Tutorial? Because when I search for similar threads, I still come across cyclic timer wake-up every x seconds, and I need to wake up the timer the same way as with EXTI. If its impossible, i eventually can change pin and use UART to wake up (if it will work :)), but i think it should be possible using timer. Thanks in advance.

10 REPLIES 10
VeryLatte
Associate II

The diode solution is the last resort because it requires me to modify the hardware and I need to have +1 GPIO pin, and I don't have them anymore. Besides, I clearly write once again that I want to wake up via TIM/UART/I2C and not EXTI. The RM says that it is possible to wake up via e.g. LPTIM and I want to do it. I don't understand why we avoid this solution since according to RM it is possible. I would like an example if there are any. For a few hours I have been trying to start waking up LPTIM1 from the ETR pin and the bit in the ISR register is setting, but it does not enter the interrupt at all. Since such a function is declared in RM, I would like an example.