UART using st-link v2-1 break up from Nucleo F446RE

[JDirk.1]

Hello,

the UART is not working.

st-link is stand alone (not connected to Nucleo anymore)

i am using a separate stm32f446ret6, tx(PIN16) and rx (PIN17) are connected to CN3 (TX/RX).

in addition the SWD CN4 of the st-link is used (all connections are made to the uC).

Programming is working fine. COM port is shown once i connect the st-link but tera term is showing nothing.

going back to a second board where the st-link is still part of the Nucleo (not break up) everything is working, uart is working.

What do you need to know to support me?

[Uwe Bonnes]

Where is the ground connection? And as a test, does shorting CN3 echo the characters you type in the terminal?

[JDirk.1]

ground is connected from CN4 (SWD) PIN 3 to ground of the uC (i think 5 times, at least 1 ground per side).

what do you mean by echo? how can i check that? i guess a multimeeter is not usable?

[JDirk.1]

if i connect Tx and Rx on CN3 (both lines together) nothing is happening on the terminal

[JDirk.1]

problem solved: i connected the tx comming from the uC to the rx of the st-link and the rx from the uC to the tx of the uC.

of course that makes sense ^^

thank you very much!!