ST-Link v3 minie unable to communicate via COM PORT

[kv_idoff]

Hi, I just bought a few ST-Link v3 minies for a project and have gotten the SWD interface to work flawlessly!

But now to my problem! I haven't gotten the COM port to work properly... I have tested to get it to work on 3 different Windows 10 computers to no avail... So to start with I have bridged RX & TX pins on the header CN4 pin 13(VCP_RX) & 14(VCP_TX), and if I connect to the com port which is visible as a generic Windows serial device, no errors are visible from putty and nothing is sent or received on the link when typing...

I then tried to install the stsw-link009@2.0.2 booth with the "dpinst_amd64.exe" and one time following the readme, booth times are the com port now discovered as "STMicroelectronics STLink Virtual COM Port" but still the results are the same as when previously tested. I also tested to connect it to a source that is known to produce data, yes I connected rx-tx and tx-rx but still, no data and just to be on the safe side did I also test with rx & tx bridged

after this did I test to update the software on the st-link booth via the latest stm32cubeprogramer but also via the standalone stsw-link007 which contains an update tool. still no difference...

oh yeah, I have tested with 3 different ST-Links as well...

Can someone please tell me what I have done wrong?!

[TDK]

It has a level shifter. It may require T_VCC to be connected to a voltage before the VCP can be used.

You can also use the pads on CN2 which may be easier.

[Pavel A.]

>I also tested to connect it to a source that is known to produce data, yes I connected rx-tx and tx-rx but still, no data 

Have you provided common ground? Voltage levels are good?

You don't tell anything about the code that runs on the target. Is there a target MCU or you just use the ST-LINK as USB to serial adapter?

[kv_idoff]

I have tested the pads on CN2 also, I have a stm32f3 processor connected with 3.3v->T-VCC and GND connected, I also have the SWD pins connected to the same MCU which works great! But there is no data through the COM PORT even though I have data from the device with other COM port adapters, I have not yet tested to see if there is any data while the SWD connection is active though but I think it should work without it...

[kv_idoff · Accepted solution]

Apparently had a bad crimp on RX for my header to the target.. so never mind works now