Unclear PA2 configuration on Nucleo-H503RB$MR3 manual

[elia_chiarucci]

Hello, after some time trying to debug the PA2 pin on my Nucleo H503 I realized, by looking at the board, that PA2 goes into SB7 and SB1.

Reading the manual it seems like both SB1 and SB7 must be off for USB Device to work, however, this will disable PA2 and doesn't seem to be documented in the manual for the H503 board (while there are some explicit SB configs for PA2 on the H533 board).

Am I missing something?

[mƎALLEm]

Hello @elia_chiarucci and welcome to the ST community,

USB device is available on PA11 and PA12 according to the board schematic:

The board user manual is shared between NUCLEO-H533 and Nucleo-H503RB. So PA2 is used as USART2 on NUCLEO-H533 while it's free in the case of Nucleo-H503RB

Hope that helps

[elia_chiarucci]

Thanks for the quick reply @mƎALLEm! I couldn't find schematics for the C revision in the ST product page but it's clear now: PA2 is connected to SB1 and SB7, which are "OFF" on the board.
This makes PA2 unavailable on the morpho and Arduino connector.

I also see that SB1 and SB7 should be off for USB Device Mode if I'm not mistaken.

Should I just bridge SB1 to bring PA2 to the morpho connector?

[elia_chiarucci · Accepted solution]

Ok I solved it, PA2 is not available on the morpho/arduino connector for H503 revision C.

It was replaced by PB1 as mentioned in the "Board revision history" but the "Pin assignment" table is not up to date, that's why I was confused.