What does "ADC1_EXTI11" mean & do in STM32CubeMX for the STM32L431RC, pin PA11, drop-down box?

[dhaselwood]

In the STM32L431, datasheet does not show PA11 as configurable to an ADC.

[waclawek.jan]

Cube/CubeMX has a dumb notion of EXTI, bound needlessly to GPIO input. In some STM32 models, ADC is connected to a pin permanently and does not require to switch that pin to Analog in GPIO (with the caveat that the digital input Schmitt trigger remains connected).

So my wild guess is that this is what you see here. You can test this hypothesis by generating code and observing it.

I don't Cube.

JW

[Khouloud ZEMMELI · Accepted solution]

Hello @Community member​ 

Thanks for your question,

Actually, the EXTI signals are not present in the Datasheet, for that you did not find the ADC1_EXTI11 there.

The ADC1_EXTI11 (which mean "extended interrupt/event controller") is a signal to Trigger the Regular Conversion for the ADC1, this signal will be automatically assigned to PA11 when it's selected through CubeMX as mentioned in the image below:

In fact, using this configuration will allow to run a conversion each time we have a signal in this pin ( Which can be trigged in the rising, falling or Rising/falling edge, depends on the configuration used). For more details about the maximum frequency that should be used in this pin, please refer to datasheet table ADC characteristics.

Hope my answer helped you, when your question is answered, please close this topic by choosing Select as Best. This will help other users find that answer faster.

Thanks for your contribution, Khouloud

[dhaselwood]

Thanks for the responses. Triggering the ADC is what I had missed in the docs.

[Ruồi]

Hello @Khouloud ZEMMELI​ 

Do you have any example of using this pin to trigger the convert of adc?

Thanks you,

Hai LV