As I understand the STM32 datasheet the default setup of PA0 and PA1 (Core A0/A1) after reset is to act as CTS/RTS pins for USART2, so just the ones that work together with RX/TX on the Core.

Is this behaviour kept intact after Core power up - as long there was no call for pinMode() on one of these?
And would Serial class support flow control, if A0/A1 are set up as CTS/RTS?

The reason why I ask is, that I’m having difficulties to get stable communication between my Core and an Roving Networks RN41 Bluetooth module when just using RX/TX (RTS/CTS bridged on the RN41 as suggested in RN datasheet).

The current serial library is based on the Arduino implementation and does no support handshaking or control lines. One could potentially control these lines manually in its current form.

Otherwise, you’ll have to modify the serial library and setup the USART module of the STM32 to do the handshaking automatically.

Thanks for this info - it’s a pitty tho’