Fail to complie RPI_PICO with MICROPY_KBD_EXCEPTION off #18348

ksprs · 2025-10-30T13:18:54Z

ksprs
Oct 30, 2025

Hello!
I was looking for a way to disable keyboard interrupts in my custom firmware build using RPI_PICO board. So prepared microptyhon with v1.26.1. The baseline setup in this version works fine. However, compilation failed when customized ports/rp2/boards/RPI_PICO/mpconfigboard.h file with this:

// Board and hardware specific configuration
#define MICROPY_HW_BOARD_NAME                   "Raspberry Pi Pico"
#define MICROPY_HW_FLASH_STORAGE_BYTES          (1408 * 1024)

// Disable exception
#define MICROPY_KBD_EXCEPTION  (0)

This is the output I see:

[ 98%] Linking CXX executable firmware.elf
/usr/lib/gcc/arm-none-eabi/14.2.1/../../../arm-none-eabi/bin/ld: CMakeFiles/firmware.dir/root/micropython/extmod/os_dupterm.c.o: in function `mp_os_dupterm_rx_chr':
/root/micropython/extmod/os_dupterm.c:159:(.text.mp_os_dupterm_rx_chr+0x7a): undefined reference to `mp_sched_keyboard_interrupt'
/usr/lib/gcc/arm-none-eabi/14.2.1/../../../arm-none-eabi/bin/ld: (mp_sched_keyboard_interrupt): Unknown destination type (ARM/Thumb) in CMakeFiles/firmware.dir/root/micropython/extmod/os_dupterm.c.o
/root/micropython/extmod/os_dupterm.c:159:(.text.mp_os_dupterm_rx_chr+0x7a): dangerous relocation: unsupported relocation
/usr/lib/gcc/arm-none-eabi/14.2.1/../../../arm-none-eabi/bin/ld: /root/micropython/extmod/os_dupterm.c:165:(.text.mp_os_dupterm_rx_chr+0x90): undefined reference to `mp_interrupt_char'
/usr/lib/gcc/arm-none-eabi/14.2.1/../../../arm-none-eabi/bin/ld: CMakeFiles/firmware.dir/root/micropython/shared/runtime/pyexec.c.o: in function `parse_compile_execute':
/root/micropython/shared/runtime/pyexec.c:114:(.text.parse_compile_execute+0x58): undefined reference to `mp_hal_set_interrupt_char'
/usr/lib/gcc/arm-none-eabi/14.2.1/../../../arm-none-eabi/bin/ld: (mp_hal_set_interrupt_char): Unknown destination type (ARM/Thumb) in CMakeFiles/firmware.dir/root/micropython/shared/runtime/pyexec.c.o
/root/micropython/shared/runtime/pyexec.c:114:(.text.parse_compile_execute+0x58): dangerous relocation: unsupported relocation
/usr/lib/gcc/arm-none-eabi/14.2.1/../../../arm-none-eabi/bin/ld: /root/micropython/shared/runtime/pyexec.c:120:(.text.parse_compile_execute+0x68): undefined reference to `mp_hal_set_interrupt_char'
/usr/lib/gcc/arm-none-eabi/14.2.1/../../../arm-none-eabi/bin/ld: (mp_hal_set_interrupt_char): Unknown destination type (ARM/Thumb) in CMakeFiles/firmware.dir/root/micropython/shared/runtime/pyexec.c.o
/root/micropython/shared/runtime/pyexec.c:120:(.text.parse_compile_execute+0x68): dangerous relocation: unsupported relocation
/usr/lib/gcc/arm-none-eabi/14.2.1/../../../arm-none-eabi/bin/ld: /root/micropython/shared/runtime/pyexec.c:129:(.text.parse_compile_execute+0xd8): undefined reference to `mp_hal_set_interrupt_char'
/usr/lib/gcc/arm-none-eabi/14.2.1/../../../arm-none-eabi/bin/ld: (mp_hal_set_interrupt_char): Unknown destination type (ARM/Thumb) in CMakeFiles/firmware.dir/root/micropython/shared/runtime/pyexec.c.o
/root/micropython/shared/runtime/pyexec.c:129:(.text.parse_compile_execute+0xd8): dangerous relocation: unsupported relocation
collect2: error: ld returned 1 exit status
make[3]: *** [CMakeFiles/firmware.dir/build.make:7237: firmware.elf] Error 1
make[2]: *** [CMakeFiles/Makefile2:2244: CMakeFiles/firmware.dir/all] Error 2
make[1]: *** [Makefile:91: all] Error 2
make[1]: Leaving directory '/root/micropython/ports/rp2/build-RPI_PICO'
-e See https://github.com/micropython/micropython/wiki/Build-Troubleshooting
make: *** [Makefile:65: all] Error 1

The same works just fine when using #define MICROPY_KBD_EXCEPTION (1).

What causes the problem?

Answered by robert-hh

Oct 30, 2025

Disabling keyboard interrupt at runtime may be sufficient for you. That's done by

import micropython
micropython.kbd_int(-1)

Re-seting Ctrl-C as interrupt can be done with
micropython.kbd_intr(3)
A transparent IO with stdin ot stdout can be done with sys.stdin.buffer.read() and sys.stdout.buffer.write().

Edit: You cannot test micropython.kbd_int(-1) ni RELP, because REPL re-enables keyboard interrupt for each prompt.

View full answer

robert-hh · 2025-10-30T14:24:09Z

robert-hh
Oct 30, 2025
Collaborator

Disabling keyboard interrupt at runtime may be sufficient for you. That's done by

import micropython
micropython.kbd_int(-1)

Re-seting Ctrl-C as interrupt can be done with
micropython.kbd_intr(3)
A transparent IO with stdin ot stdout can be done with sys.stdin.buffer.read() and sys.stdout.buffer.write().

Edit: You cannot test micropython.kbd_int(-1) ni RELP, because REPL re-enables keyboard interrupt for each prompt.

0 replies

ksprs · 2025-10-30T14:39:42Z

ksprs
Oct 30, 2025
Author

Thanks! This solves the problem for the moment.

It would be good to fix it when using MICROPY_KBD_EXCEPTION macro.

2 replies

scruss Nov 3, 2025
Sponsor

How would the REPL manage keyboard input if the keyboard interrupt wasn't available? If you turn off keyboard interrupts, it's a given that you won't be needing the REPL

ksprs Nov 4, 2025
Author

Actually, REPL is still useful for serial communication using stdin/stdout. By disabling keyboard interrupt I want to prevent script termination from client side.

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