ST-Link and the UART connection

[Uwe Bonnes]

Posted on October 10, 2013 at 15:12

Hello,

recent discovery boards have a jumperable UART connection between the debugger and the target device. Is there any way to read/write to ther serial link with the PC?

#pc #uart #stlink

[hmc]

Posted on January 24, 2016 at 20:04

I assume you are talking about this part (for example on the stm32f429-disco).

It's not a jumper per se (at least on the stm32f429-disco); just a solder bridge that you can fill and connect to PA9/10 if you want.  I was scratching my head also, until I found in the ST-Link manual that the USART pins on ST-Link are ''reserved'' (meaning: not implemented yet).

Someone please correct me if I am wrong.  So far, the most direct answer for connecting to stm32f429-disco USART is

http://www.emcraft.com/stm32f429discovery/connecting-serial-console-to-stm32f429

.

[Tesla DeLorean]

Posted on January 24, 2016 at 20:38

This is a bit of an old post.

The ''Newer'' DISCO's in 2016 context support mbed, and have a bigger F103 part and ST-LINK V2.1 firmware that support a VCP which the drivers instantiate a COMx port on the Windows side.

The NUCLEO's have supported this for a while, the F746 and F469 DISCO also support it. The older F40x and F429 DISCO do not.

[mnikhilesh]

I know its an old thread, but can someone please confirm if my understanding is correct.

I can see that there is a connection between STLink Microcontroller (F103CB) UART and Target UART. Like its seen in below image. Is this UART used for the virtual COM port that is created by STLink to send data from target to computer while debugging? I always thought that the data is coming through the debugging channel (SWD). Never really paid attention until i saw this connection.

[Uwe Bonnes]

Your understanding is right. VCOM is coming from target U(S)ART.