swaits
6db287c241
The default heltec_v3 feature now uses native USB OTG (same as V4), appearing as /dev/ttyACM0 with the DongLoRa VID:PID (1209:5741). This requires a hardware mod: solder R29/R3 and disconnect the CP2102 from the USB data lines. Stock (unmodified) V3 boards should use the new heltec_v3_uart feature which preserves the original UART-over-CP2102 behavior (/dev/ttyUSB0). - heltec_v3: switched from UART to USB OTG - heltec_v3_uart: new feature, UART fallback for stock boards - Removed #[cfg] gates on UsbParts/UartParts (both always defined) - Updated README with hardware mod instructions and board table - Updated justfile with heltec_v3_uart board definition
62 lines
2.1 KiB
Markdown
62 lines
2.1 KiB
Markdown
# DongLoRa Firmware
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Embedded Rust firmware for DongLoRa boards. Exposes the LoRa radio over
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USB CDC-ACM using a COBS-framed binary protocol.
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## Building
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```sh
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just setup # one-time toolchain install
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just build heltec_v4 # build for a specific board
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just flash heltec_v4 # build + flash
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just check-all # compile-check all boards
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just clippy heltec_v4 # lint
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just test # host-side protocol unit tests
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```
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All commands are run from the `firmware/` directory.
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## Supported Boards
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| Board | Feature | MCU | Radio | USB | Target |
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|-------|---------|-----|-------|-----|--------|
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| Heltec V3 | `heltec_v3` | ESP32-S3 | SX1262 | Native CDC-ACM | xtensa-esp32s3-none-elf |
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| Heltec V3 (UART) | `heltec_v3_uart` | ESP32-S3 | SX1262 | CP2102 bridge | xtensa-esp32s3-none-elf |
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| Heltec V4 | `heltec_v4` | ESP32-S3 | SX1262 | Native CDC-ACM | xtensa-esp32s3-none-elf |
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| RAK WisBlock 4631 | `rak_wisblock_4631` | nRF52840 | SX1262 | Native CDC-ACM | thumbv7em-none-eabihf |
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| Wio Tracker L1 | `wio_tracker_l1` | nRF52840 | SX1262 | Native CDC-ACM | thumbv7em-none-eabihf |
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### Heltec V3 USB Note
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The default `heltec_v3` build uses **native USB CDC-ACM**, which requires a
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hardware modification to your board. Stock Heltec V3 boards route USB through a
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CP2102 bridge chip to UART — the ESP32-S3's native USB pins (GPIO19/GPIO20) are
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routed to header pins but not connected to the USB connector.
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**To enable native USB on a Heltec V3:**
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1. Solder 0-ohm (or 22-ohm) resistors at pads **R29** (D+) and **R3** (D-)
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2. Disconnect the CP2102 from the USB connector's D+/D- lines (cut traces or
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remove the CP2102 bridge resistors)
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After this mod, the board appears as `/dev/ttyACM0` with the DongLoRa VID:PID
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(1209:5741), just like the V4 and nRF boards.
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**If you have a stock (unmodified) V3**, use `heltec_v3_uart` instead:
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```sh
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just build heltec_v3_uart
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just flash heltec_v3_uart
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```
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This builds firmware that communicates via the CP2102 bridge (appears as
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`/dev/ttyUSB0`).
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## Adding a Board
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See [src/board/PORTING.md](src/board/PORTING.md).
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## Protocol
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See [PROTOCOL.md](PROTOCOL.md) for the complete wire format specification.
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