Use jtag uart

[Divesh Dutt]

Hi can i use the same uart as my JTAG debugger uses to communicate with my Lidar i am using nucleo-64 board.It is uses pins PA2 and PA3 to load the program?

[Tesla DeLorean]

I don't think JTAG debuggers use USART.

If you're using the ST-LINK on the NUCLEO, you should be able to use the PB3 SWO pin and have two way comms to the debugger using the Serial Wire Viewer (SWV) on CM3/CM4/CM7 cores which is independent of the USART.

The USART/VCP combo on the NUCLEO-64 tends to conflict with the ARDUINO shield connectivity, you want to commit to one or the other.

[Divesh Dutt]

How can i use switch pb3 to switch UART from debugger to communication?

[Tesla DeLorean]

The SWV uses the ITM_SendChar() function, on the PC side Keil and TrueStudio etc, and the ST-LINK Utilities proved a debug console.

http://www.keil.com/appnotes/files/apnt_230.pdf

PB3 is part of the JTAG pins, on some ST boards you need to double check that a Solder-Bridge is made. This is not supported on the CM0 parts, but then neither is JTAG