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>
27 lines
530 B
TOML
27 lines
530 B
TOML
[package]
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name = "wiredsensor-bridge"
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description = "Turns a spare RP2040 into a USB-to-RS485 bridge for testing the bus"
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version.workspace = true
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edition.workspace = true
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license.workspace = true
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[[bin]]
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name = "wiredsensor-bridge"
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path = "src/main.rs"
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test = false
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bench = false
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[dependencies]
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rp2040-hal = { version = "0.12", features = ["rt", "critical-section-impl"] }
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rp2040-boot2 = "0.3"
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cortex-m = "0.7"
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cortex-m-rt = "0.7"
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embedded-hal = "1.0"
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fugit = "0.3"
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usb-device = "0.3"
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usbd-serial = "0.2"
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panic-halt = "1.0"
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