I am going a bit crazy about this. I have a custom board with STM32412 on it.
I have connected TX and RX to PA9 and PA10, I ensure that Boot0 == 1 and PB2 (boot1) == 0 (just in case). As per AN2606.
And the board doesn't respond to 0x7F.
The same setup with the NUCLEO evaluation board works fine! I use a UM232R @ 3v3 both TX and RX are pulled up internally
What am I missing?
The MCU on the board was tested in its virgin state ( from the box ) and also after programming using JTAG to check if it works?
Any clues or pointer would be much appreciated?