Hi,
I've been trying to get some printf()- UART/USB debug info via the "pico_enable_stdio_usb" functions.
Unfortunately, while I get a COM port appearing on the PC, there's nothing being received from the RP2350.
Things I've tried:
Going back to the basic hello_usb, no success.
Setting hello_usb to serial in the cmakelist - I can then see the "Hello world" string being sent over GPIO UART.
Multiple terminal programs, including my own - can't see any bytes over USB.
Changing the virtual baud rate, parity etc - no luck.
Toggling an LED with each printf - the CPU is definitely running in USB mode
Checking SDK versions - 2.2, says it's up to date.
I've also tried other CDC USB projects - they work fine, I've emulated keyboards, joysticks, UART without problems. I could pull all that into my project, but I like the simplicity of the stdio_usb libraries for temporary debugging.
So I was starting to wonder if there's something up with printf and the built-in libraries taking it out on USB, but others must use it for C/C++ projects without problems?
I've been trying to get some printf()- UART/USB debug info via the "pico_enable_stdio_usb" functions.
Unfortunately, while I get a COM port appearing on the PC, there's nothing being received from the RP2350.
Things I've tried:
Going back to the basic hello_usb, no success.
Setting hello_usb to serial in the cmakelist - I can then see the "Hello world" string being sent over GPIO UART.
Multiple terminal programs, including my own - can't see any bytes over USB.
Changing the virtual baud rate, parity etc - no luck.
Toggling an LED with each printf - the CPU is definitely running in USB mode
Checking SDK versions - 2.2, says it's up to date.
I've also tried other CDC USB projects - they work fine, I've emulated keyboards, joysticks, UART without problems. I could pull all that into my project, but I like the simplicity of the stdio_usb libraries for temporary debugging.
So I was starting to wonder if there's something up with printf and the built-in libraries taking it out on USB, but others must use it for C/C++ projects without problems?
Statistics: Posted by Beaumotplage — Sun Dec 14, 2025 9:31 am