General troubleshooting

cargo-embed problems

Most cargo-embed problems are related to not having installed the udev rules properly on Linux, so make sure you got that right.

If you are stuck, you can open an issue in the discovery issue tracker or visit the Rust Embedded matrix channel or the probe-rs matrix channel and ask for help there.

Cargo problems

"can't find crate for core"

Symptoms:

   Compiling volatile-register v0.1.2
   Compiling rlibc v1.0.0
   Compiling r0 v0.1.0
error[E0463]: can't find crate for `core`

error: aborting due to previous error

error[E0463]: can't find crate for `core`

error: aborting due to previous error

error[E0463]: can't find crate for `core`

error: aborting due to previous error

Build failed, waiting for other jobs to finish...
Build failed, waiting for other jobs to finish...
error: Could not compile `r0`.

To learn more, run the command again with --verbose.

Cause:

You forgot to install the proper target for your microcontroller thumbv7em-none-eabihf.

Fix:

Install the proper target.

$ rustup target add thumbv7em-none-eabihf

Unable to flash the device: No loadable segments were found in the ELF file

Symptoms:

> cargo embed
    Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.04s
      Config default
      Target /home/user/embedded/target/thumbv7em-none-eabihf/debug/examples/init
 WARN probe_rs::flashing::loader: No loadable segments were found in the ELF file.
       Error No loadable segments were found in the ELF file.

Cause:

Cargo needs to know how to build and link the program to the requirements of the target device. You therefore need to set the correct parameters in the .cargo/config.toml file.

Fix:

Add a .cargo/config.toml file with the correct parameters:

[build]
target = "thumbv7em-none-eabihf"

[target.thumbv7em-none-eabihf]
runner = "probe-rs run --chip nRF52833_xxAA"
rustflags = [
  "-C", "linker=rust-lld",
]

See Embedded Setup for further details.