STM32C031F6 CubeMX pin assignment for USART1 boot loader use

[rcagle]

I'm trying to understand the USART1 boot loader operation on STM32C031F6P6. AN606 rev 63 pg 53 says USART1 Rx/Tx must be on PA11/PA12 (TSSOP20), but CubeMX 6.11.1 does not let me assign those functions to those pins. CubeMX wants to assign USART1_TX to PB6, PA0, or PC14, but none of those match what is in AN606 for USART1 boot loader operation.

[Tesla DeLorean]

AN2606

External pins are bonded together with multiple IO. See Data Sheet PA12<>PA10, PA11<>PA9, USART1

"On TSSOP20 and UFQFN28 packages USART1 PA9/PA10 IOs are remapped on
PA11/PA12."

https://www.st.com/resource/en/application_note/an2606-stm32-microcontroller-system-memory-boot-mode-stmicroelectronics.pdf