Oliver Walter
ddfda14085
Makes end-to-end verification of the bus possible with a spare RP2040 and no dedicated RS485 dongle. bridge/ turns a second Pico into a transparent USB-to-RS485 bridge. It is deliberately protocol-agnostic: bytes from USB go out on the pair, bytes from the pair go back up USB, and it knows nothing about frames, addresses or CRCs. A protocol-aware bridge could have a bug that happens to agree with the node's own, which would defeat the point of using it as a test instrument. It also needs no register-level code — it never has to delimit a frame, and the one thing it does need, knowing that the final stop bit has cleared the shifter before releasing DE, rp2040-hal exposes as uart_is_busy(). tools/wiredsensor.py is an independent implementation of the wire format, written from the specification in README.md rather than sharing code with wiredsensor-core. Shared code would let a framing or CRC bug cancel out and every test pass regardless. Cross-checked: it reproduces the CRC-16/MODBUS catalogue vector and builds byte-identical frames to the Rust side for all five documented examples. Its `test` subcommand covers what host tests structurally cannot, all of it timing-dependent: that malformed and mis-addressed frames leave the node silent rather than colliding with whoever was actually addressed, that the driver-enable turnaround leaves replies intact, and that no state leaks between back-to-back frames. Uses one wiring diagram for both boards, since the bridge mirrors the node's GPIO0/1/2 assignment. Frames must fit one 64-byte USB packet, as each host write becomes exactly one DE-bracketed transmission; every real command is at most 21 bytes. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
19 lines
853 B
Rust
19 lines
853 B
Rust
use std::{env, fs, path::PathBuf};
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fn main() {
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// Copy memory.x somewhere the linker will find it. Relying on the linker's
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// working directory does not work in a workspace, where cargo runs rustc
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// from the workspace root rather than this package's directory.
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let out = PathBuf::from(env::var("OUT_DIR").expect("OUT_DIR"));
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fs::copy("memory.x", out.join("memory.x")).expect("copy memory.x into OUT_DIR");
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println!("cargo:rustc-link-search={}", out.display());
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// --nmagic disables page alignment of sections; without it the vector table
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// is pushed away from the start of flash and the boot ROM cannot find it.
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println!("cargo:rustc-link-arg-bins=--nmagic");
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println!("cargo:rustc-link-arg-bins=-Tlink.x");
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println!("cargo:rerun-if-changed=memory.x");
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println!("cargo:rerun-if-changed=build.rs");
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}
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