Cargo aliases

Picodroid intentionally ships no default cargo target — [build] target = ... is not set in .cargo/config.toml. Bare cargo build therefore errors with a clear “no target specified” message instead of silently mistyping the build (the previous default of thumbv6m-none-eabi made every RP2350 IDE build silently wrong).

Pick a board explicitly using one of the aliases below, or use the wrapper scripts in scripts/.

RP family (RP2040 / RP2350)

Alias	Equivalent invocation
cargo b-testbench-rp2040	cargo build -p picodroid --target thumbv6m-none-eabi --no-default-features --features board-testbench-rp2040
cargo b-testbench-rp2350	cargo build -p picodroid --target thumbv8m.main-none-eabihf --no-default-features --features board-testbench-rp2350
cargo b-testbench-rp2350w	cargo build -p picodroid --target thumbv8m.main-none-eabihf --no-default-features --features board-testbench-rp2350w
cargo b-pico-enviro-mon	cargo build -p picodroid --target thumbv8m.main-none-eabihf --no-default-features --features board-pico-enviro-mon
cargo b-pico-touch-kit	cargo build -p picodroid --target thumbv8m.main-none-eabihf --no-default-features --features board-pico-touch-kit
cargo b-sim	cargo build -p picodroid --no-default-features --features sim,board-testbench-rp2350 (host target)

pico_enviro_mon_w and pico_display2_w have no alias. Build them through the scripts (./scripts/build.sh --board pico_display2_w), or spell the invocation out with --features board-pico-enviro-mon-w / board-pico-display2-w and the RP2350 target.

What an alias does not do

An alias is the bare cargo invocation, which makes it the right tool for a compile check and for rust-analyzer, and the wrong one for an image you mean to boot. scripts/build.sh and scripts/flash.sh do four things around the same command:

• They build the app’s PAPK and the board’s system apps first and pass the PAPK as PICODROID_APK_PATH. Without that variable the build embeds no app and an empty framework class table, so the firmware links and boots with no Java classes at all.
• They pass --config profile.dev.debug-assertions=false and --config profile.dev.overflow-checks=false to every firmware build, and --config profile.release.lto=false on the RP2040. A debug build without the first two is about 41 KB larger.
• They add the line-numbers feature to a debug build on the RP2350 boards (never on the RP2040, never to --release; PICODROID_LINE_NUMBERS=0|1 overrides) and pack the PAPK with its line tables to match.
• They print the flash, RAM and main-stack figures of the linked image and fail a build whose main stack is under the 8,192-byte floor.

r-* variants

r-* variants run cargo run instead of cargo build. RP boards use the probe-rs runner configured as runner = ... under the matching [target.*] block in .cargo/config.toml.

Those blocks are keyed by cfg, not by target triple. One table, cfg(all(target_arch = "arm", target_os = "none")), carries the linker (flip-link) and the link arguments for both chips; two more add target_abi = "eabi" (RP2040, probe-rs run --chip RP2040) and target_abi = "eabihf" (RP2350, probe-rs run --chip RP235x) for the runner. Cargo reads a table named by the dotted triple thumbv8m.main-none-eabihf only unquoted up to 1.98 and only quoted from nightly 1.101, so either spelling dropped the RP2350 link arguments on one toolchain; a cfg key has no dots. A runner goes through probe-rs directly and takes no bench lease; on a shared bench use scripts/flash.sh.

Adding a new board

Mechanical: register b-<board> and r-<board> aliases pointing at the new board feature and matching MCU target triple. For RP, edit .cargo/config.toml at the repo root. The linker, link arguments and runner come from the cfg tables and need no entry per board.

rust-analyzer

rust-analyzer invokes cargo directly without the alias machinery, so it needs to be told which target and feature set to use for analysis. Set the following in your editor’s workspace settings, swapping the values for whichever board you are currently working on:

VS Code (.vscode/settings.json)

{
  "rust-analyzer.cargo.target": "thumbv8m.main-none-eabihf",
  "rust-analyzer.cargo.noDefaultFeatures": true,
  "rust-analyzer.cargo.features": ["board-testbench-rp2350"],
  "rust-analyzer.check.extraArgs": [
    "--target", "thumbv8m.main-none-eabihf",
    "--no-default-features",
    "--features", "board-testbench-rp2350"
  ]
}

For sim work, set "rust-analyzer.cargo.features": ["sim", "board-testbench-rp2350"] and remove the target entries.

Other editors

Pass the same --target / --no-default-features / --features flags via your editor’s cargo.extraArgs (or equivalent) hook.