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submitted 2 years ago* (last edited 2 years ago) by [email protected] to c/[email protected]

Hi all. Tho I have this problem a long time, I try to ask here too.

When I use PicoProbe for debug my code with Visual Studio Code (or Codium), can't get serial monitor working on the target Pico.

I have hooked up everything correctly, the probe's Rx/Tx GPIOs are connected to the target's UART0 Tx/Rx correctly (checked it, Tx-Rx and Rx-Tx, swapped it, no data at all. Tried to touch the wires to random spots, garbage appeared on the serial monitor, so the probe is probably listening)

Using USB as UART, connected directly to the target device does give me serial output, but through the probe and with UART, absolutely nothing.

I used the 'hello_serial' example project, built it with Codium (or VSCode), using the same plugins the pico_installer would setup. (MS CMake Tools, MS C++ tools and Cortex debug).

Debugging with openocd, or just running the built firmware on it's own and listening to it with the probe has the same result: nothing.

Same on Windows, same on Linux.

Anyone has any idea? I can program the Picos this way, but I really need serial for debugging. I could use two USB cables, but soonly enough that won't work.

Am I missing something? I did lots of search, but this feature should just work.

edit: fixed some typos

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[-] [email protected] 0 points 2 years ago* (last edited 2 years ago)

right now my setup, which only the "debugger/programmer" consists one breadboard with two picos; one for the debugger and one for serial monitoring, with two USB cables. it's messy, but works, tho I shouldn't need it to be this messy.

for some reason, the RX/TX just gets pulled up high and that's it, probably by the Probe if it's on its own.

[-] [email protected] 1 points 5 days ago

It may be caused by you didn't connect GND. So debugger and board has different ground level and it looks like RX/TX were pull up because 0V on one side is equal to a higher voltage on another side.

[-] [email protected] 1 points 5 days ago

It was a while ago I last messed with the Pico, but if I remember correctly, they shared the same ground, but I might be wrong.

Strange thing is, if I use a different set of UART pins (UART1 or even if I define one myself) the serial logging works as it should, so it seems like only UART0 is affected by this.

So... using other TX/RX pins works, just inconvenient sometimes.

Thanks for the input!

this post was submitted on 03 Oct 2023
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