embassy-rs/embassy · error

No mspm0xx/mspsxx Cargo feature enabled

Error message

No mspm0xx/mspsxx Cargo feature enabled

What it means

embassy-mspm0's build script generates chip-specific register/peripheral code based on exactly one enabled chip Cargo feature (e.g. mspm0g350x). When the environment contains no variable starting with CARGO_FEATURE_MSPM0 or CARGO_FEATURE_MSPS, `get_one` returns `GetOneError::None` and the build script panics, failing the build with this message.

Solutions

1. Enable exactly one chip feature in Cargo.toml, e.g. `embassy-mspm0 = { version = "...", features = ["mspm0g350x"] }` matching your actual MCU.
2. If features are set on a sibling crate, re-export/forward them or enable them directly on embassy-mspm0.
3. Check `cargo build -v` / `cargo tree -f '{p} {f}'` that the feature is active in the unit being compiled.

Example fix

// before (Cargo.toml)
embassy-mspm0 = { version = "0.1", default-features = false }
// after
embassy-mspm0 = { version = "0.1", features = ["mspm0g350x"] }

// Cargo.toml — exactly one chip feature required:
// [dependencies]
// embassy-mspm0 = { version = "0.1", features = ["mspm0g350x"] }

When it happens

Trigger: Adding `embassy-mspm0` as a dependency with `default-features = false` and no chip feature like `mspm0g350x` enabled; building a workspace where the feature lives on another crate and isn't forwarded.

Common situations: Creating a new project from scratch without copying the chip feature line from an example; upgrading embassy and losing default features; trying to compile the crate standalone (`cargo build` inside the crate dir without features).

Related errors

• Multiple mspm0xx/mspsxx Cargo features enabled
• Multiple time-driver-xxx Cargo features enabled
• unknown time_driver
• Multiple stm32xx Cargo features enabled
• No stm32xx Cargo feature enabled

AI-assisted analysis of embassy-rs/embassy@463a07b963 (2026-09-10). Data as JSON: /api/errors/7ccc31f438b9b901. Report an issue: GitHub.

Appendix: source

Thrown at embassy-mspm0/build.rs:42

    interrupt_group_linker_magic();
}

fn generate_code(cfgs: &mut CfgSet) {
    #[cfg(any(feature = "rt"))]
    println!(
        "cargo:rustc-link-search={}",
        PathBuf::from(env::var_os("OUT_DIR").unwrap()).display(),
    );

    cfgs.declare_all(&["gpio_pb", "gpio_pc", "int_group1", "unicomm"]);

    let chip_name = match env::vars()
        .map(|(a, _)| a)
        .filter(|x| x.starts_with("CARGO_FEATURE_MSPM0") || x.starts_with("CARGO_FEATURE_MSPS"))
        .get_one()
    {
        Ok(x) => x,
        Err(GetOneError::None) => panic!("No mspm0xx/mspsxx Cargo feature enabled"),
        Err(GetOneError::Multiple) => panic!("Multiple mspm0xx/mspsxx Cargo features enabled"),
    }
    .strip_prefix("CARGO_FEATURE_")
    .unwrap()
    .to_ascii_lowercase()
    .replace('_', "-");

    eprintln!("chip: {chip_name}");

    cfgs.enable_all(&get_chip_cfgs(&chip_name));
    for chip in ALL_CHIPS {
        cfgs.declare_all(&get_chip_cfgs(&chip));
    }

    let mut singletons = get_singletons(cfgs);

    time_driver(&mut singletons, cfgs);
    pin_features(&mut singletons);

View on GitHub (pinned to 463a07b963)