Reasons for usart1 nor usart3 not working after st-link programer cut-off on stm32l476rg development board.

[protonone]

Hello,

i would like to know why after st-link programer has been cut-off usart1(pa9,pa10) and usart3(pb10,pb11) doesn't work at all.

Any help would be appreciated.

Thanks

[Tesla DeLorean]

IO side power supply

Double check the schematic, and probe salient points on the PCB

[protonone]

Thanks for the prompt reply.

For now, i don't have any probe to test with.

The board is powered with 5V on E5V and i've also done some tests with 3V but none of them work.

I don't know where or what to look for.

[Tesla DeLorean]

Perhaps you can expand on the testing you did to determine how USART1 and USART3 failed, how you have them wired up and to what.