STM32CubeF3V1.11.6 official inspected example: Projects/STM32F3-Discovery/Examples/UART/UART_TwoBoards_ComIT/Src/main.c, Src/stm32f3xx_it.c, Inc/main.h. USART2PD5/6 9600 fixed arrays adapted toUSART1PA9/10 115200 and original SPSC/parser.
https://github.com/STMicroelectronics/STM32CubeF3/tree/663d2baae3604244f90ed80d0d757df17e36ada9/Projects/STM32F3-Discovery/Examples/UART/UART_TwoBoards_ComIT
https://github.com/STMicroelectronics/stm32f3xx_hal_driver/tree/953955afe65f89e60e556bbcdba752597f5da65d
https://www.st.com/st-web-ui/static/active/en/resource/technical/document/reference_manual/DM00043574.pdf
https://www.st.com/resource/en/datasheet/stm32f303cb.pdf
https://gebrabit.com/wp-content/uploads/2024/07/GebraBit-STM32F303-Schematic-V2.0.pdf
PA9physical30 TX,PA10physical31 RX,AF7; sharedGND andcompatible3.3Vlogic. Actual HAL supportsReceiveToIdle_IT but IDLEisnotpacketframing andITstillusesbyteinterrupts. ORE/RTO blocking, FE/NE/PE canbecontinuable; applicationconservativelyrecoversallnotifiederrors.
