7 years, 10 months ago.  This question has been closed. Reason: Duplicate question

STLink second board programming STM32L4 VDD and TX/RX garbage question.

I can use an Nucleo STLink board successfully to connect my own board. Using the CN2 and CN4 connectors. This allows to use mbed with my own board. I have some questions, maybe somebody has some ideas.

1. VDD on CN4 Is the VDD connection needed? It works without it but I don't know if this is correct. My board uses a battery which means the voltage is 2.2-3V depending on the battery.

2. Flashing new .bin files produces garbage in USB RX/TX console The USB disk flashing works but it starts with three lines garbage on the tty, than it flashes and starts the application. I don't have this garbage when I work with the STM32L4 MCU on the Nucleo board. My baud rate is 230400.

Regards Helmut