setup_default_uart() error

[Dj-EKI]

In both versions. 2.7.3 and 3.0.0
setup_default_uart();
Generates this error.

c:/users/reder/appdata/local/arduino15/packages/rp2040/tools/pqt-gcc/1.5.0-b-c7bab52/bin/../lib/gcc/arm-none-eabi/10.3.0/../../../../arm-none-eabi/bin/ld.exe: C:\Users\reder\AppData\Local\Arduino15\packages\rp2040\hardware\rp2040\3.0.0/lib/libpico.a(stdlib.c.obj): in function `setup_default_uart':
/home/earle/Arduino/hardware/pico/rp2040/pico-sdk/src/rp2_common/pico_stdlib/stdlib.c:94: undefined reference to `stdio_uart_init'
collect2.exe: error: ld returned 1 exit status

Maybe I'm using the function incorrectly. The sleep_run_from_xosc(); uses this function and produces the same error. sleep_run_from_xosc(); is from Pico-extras.

[earlephilhower]

You cannot call stdio_uart_init in this core. The Arduino Serial/Serial1/Serial2 ports already take control of the UART and USB.

Use Serial1 for UART0 and Serial2 for UART1. Serial is USB. Then Serial.printf("dddd"); will just work, no SDK stuff needed.

[earlephilhower]

One more thing, if you set the Tools->Debug Port->Serial/1/2, then plain printf() will go to that specific port (i.e. printf is not Arduino-like and normally only a debug thing).