Raspberry Pico, Thonny and serial output

[MatzeZett]

Hello to everybody.

It seems to be quite a simple task but I cannot figure out why it doesn't work.

The Pico is connected to a Windows PC by an ordinary USB cable.
Programming works fine, so the cable must be intact.

What I want from the Pico is:
He should send me a string in every second.
What I write is:

import time
print('string\r\n')
time.sleep(1)

I can see the string in the console of Thonny.
Closing Thonny ( to release the COM-Port) and opening a terminal software also shows me this string every second.
But this only works with the serial Monitor of the Arduino-IDE and with Putty.

If i use hTerm or my own software ( which works perfectly with an Arduino nano in the same way) it shows nothing.

What I wonder is:
How does this micropython script know which baudrate it has to use?

Any help is veeery welcome.
Cheers,
Matt

[jimmo]

print('string\r\n')

You shouldn't include the \r here -- the \r is added automatically in MicroPython's serial output code. Just write print('string') and if you want an extra newline, then just print('string\n').

If i use hTerm or my own software ( which works perfectly with an Arduino nano in the same way) it shows nothing.

The fact that it works in the other programs is interesting. Does mpremote work?

How does this micropython script know which baudrate it has to use?

There's no baud rate involved when talking over USB. It's a fake serial port (a CDC ACM device). When you set a baud rate, it's send to the Pico, but ignored by MicroPython.

This does matter when you're talking to a microcontroller that doesn't natively support USB and instead it's via a USB to UART converter on the board (e.g. an ESP32 and many older Arduino boards) -- the baud rate send to the USB/UART converter is then used to configure the UART that talks to the actual chip).

[MatzeZett]

Maybe somebody has a Raspberry Pico and can try to use hTerm and tell me if you get a result?

[jimmo]

OK I tried it. Have you clicked the "DTR" button in hTerm? (Other programs enable this by default)

[jimmo]

hTerm is really not an ideal program to use with MicroPython because it's line oriented. It's also just really confusing. You want a "true" terminal (like Putty or mpremote). Again this DTR issue is because of the difference between FTDI (e.g. Arduino Nano) and an ACM device (Pico, and many others). You would see the same issue using hTerm with an Arduino Leonardo or many of the newer Arduino boards.

If you're looking for a beginner-friendly option for getting started with MicroPython, maybe try Thonny.

[MatzeZett]

jimmo - you're great !

DTR was the solution!
Now I get the desired Data on hTerm.

Yes, I already use Thonny. Great for beginners like me.
hTerm was just another one to double-check the output of the Pico.

OK, so now I have to find out why my own software does not receive data.

Thanks a lot
I will get back to you as soon as I can figure out something new.

Best wishes,
Matt

[MatzeZett]

In my C++ code I added DtrEnable = True

And now: Everythings is running great !!! Yippie

Many thanks again to you, without your help I wouldn't have been able to solve the problem.

Are you a model railroader?