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Elliott99
Associate II
February 17, 2025
Solved

STM32L431: Enable EXTI on a Pin Number Used as UART RX on a Different Port

  • February 17, 2025
  • 2 replies
  • 651 views

Hello,

I would like to configure PA11 as an EXTI pin. I know that there exists the hardware limitation that there cannot exist two pins with the same pin number in different ports configured as an EXTI pin (I.E., I could not configure both PB11 and PA11 as EXTI inputs). PB11 is already configured as a UART RX pin. Will there be any conflict if I now attempt to configure PA11 as an EXTI input pin, I.E. a low bit being received by PB11 triggers the EXTI interrupt on pin 11? Or does this conflict only occur when two pins of the same number are both configured as EXTI inputs? 

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Best answer by mƎALLEm

Hello,

No. There is no relation between UART Rx and EXTI interrupt. These lines are totally different. No risk to get EXTI triggered by the UART Rx.

2 replies

mƎALLEm
mƎALLEmBest answer
ST Technical Moderator
February 17, 2025

Hello,

No. There is no relation between UART Rx and EXTI interrupt. These lines are totally different. No risk to get EXTI triggered by the UART Rx.

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TDK
TDK
February 17, 2025

Furthermore, it is not possible to configure two pins of the same number as EXTI inputs.

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