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BEKABEN
Associate II
May 4, 2023
Solved

Hi In the STM32L053R8 Datasheet, I cannot figure out the default alternative function AF0, AF1... I'm using the UART TX RX on PA10 PA9 is that the correct choice?

  • May 4, 2023
  • 6 replies
  • 1759 views

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This topic has been closed for replies.
Best answer by Tesla DeLorean

AF4 is set by software.

If you used PA9/PA10 for a UART connection in your design it will be usable as such.

​

F​or the System Loader see App Note AN2606 for supported PINS and METHODS.

6 replies

Foued_KH
ST Employee
May 4, 2023

Hello @BEKABEN​ ,

Correct, for UART instance 1 : PA9/PB6 -> UART1_TX and PA10/PB7 -> UART1_RX

For LPUART : PB10/PC4/PC10 -> LPUART1_TX and PC5/PC11 -> LPUART1_RX

Also, for UART instance 2 : PA2/PA14 -> UART2_TX and PA3/PA15 -> UART2_RX

Foued

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waclawek.jan
Super User
May 4, 2023


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JW

BEKABEN
BEKABENAuthor
Associate II
May 5, 2023

Yes

is AF4 the default setting on the stm32l053r8?

waclawek.jan
Super User
May 5, 2023

No.

Default setting of all AF is AF0 - see GPIO_AFR registers description in the GPIO chapte of Reference Manual.

JW

BEKABEN
BEKABENAuthor
Associate II
May 6, 2023

If I design my schematic based on AF4 and I'm accessing the UART from PA9 PA10 is it possible to do updates in the future?

Tesla DeLorean
Tesla DeLoreanBest answer
Guru
May 6, 2023

AF4 is set by software.

If you used PA9/PA10 for a UART connection in your design it will be usable as such.

​

F​or the System Loader see App Note AN2606 for supported PINS and METHODS.

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