swaits
8b549d49a9
ESP32-S3 + SX1262 + 1.3" SH1106 OLED + CP2102 UART bridge +
1000 mAh Li-Po. Pin map verified against Meshtastic's
variants/esp32s3/ELECROW-ThinkNode-M2. DIO3 TCXO at 3.3 V (vs 1.8 V
on Heltec), VEXT_ENABLE active HIGH (opposite polarity), dedicated
LORA_POWER_EN on GPIO48 sequenced before SPI init. Reuses the
existing async SH1106 driver at I2C address 0x3C.
Refactors hal::esp32s3::{init_spi,init_i2c} and board::esp32s3::init_radio
to accept generic GPIO bounds so ESP32-S3 boards with different pin
assignments can share the helpers. init_radio now takes a
TcxoCtrlVoltage parameter instead of hardcoding Ctrl1V8.
Incidental cleanups needed to make `just check-all` green:
- Replace the core::mem::forget(output) pattern with let _foo = ...;
current esp-hal makes Output non-Drop, so forget is a no-op that
trips clippy's forget_non_drop lint.
- Switch justfile xtensa builds from `cargo +nightly` with a RUSTC
override to `cargo +esp` so the compiler and rust-src versions stay
aligned. Public nightly's rust-src had drifted two months ahead of
the esp fork and broke -Zbuild-std on core.
DongLoRa Firmware
Embedded Rust firmware for DongLoRa boards. Exposes the LoRa radio over USB CDC-ACM using a COBS-framed binary protocol.
Building
just setup # one-time toolchain install
just build heltec_v4 # build for a specific board
just flash heltec_v4 # build + flash
just check-all # compile-check all boards
just clippy heltec_v4 # lint
just test # host-side protocol unit tests
All commands are run from the firmware/ directory.
Supported Boards
| Board | Feature | MCU | Radio | USB | Target |
|---|---|---|---|---|---|
| Heltec V3 | heltec_v3 |
ESP32-S3 | SX1262 | Native CDC-ACM | xtensa-esp32s3-none-elf |
| Heltec V3 (UART) | heltec_v3_uart |
ESP32-S3 | SX1262 | CP2102 bridge | xtensa-esp32s3-none-elf |
| Heltec V4 | heltec_v4 |
ESP32-S3 | SX1262 | Native CDC-ACM | xtensa-esp32s3-none-elf |
| ELECROW ThinkNode-M2 | elecrow_thinknode_m2 |
ESP32-S3 | SX1262 | CP2102 bridge | xtensa-esp32s3-none-elf |
| RAK WisBlock 4631 | rak_wisblock_4631 |
nRF52840 | SX1262 | Native CDC-ACM | thumbv7em-none-eabihf |
| Waveshare RP2040-LoRa | waveshare_rp2040_lora |
RP2040 | SX1262 | Native CDC-ACM | thumbv6m-none-eabi |
| Wio Tracker L1 | wio_tracker_l1 |
nRF52840 | SX1262 | Native CDC-ACM | thumbv7em-none-eabihf |
Heltec V3 USB Note
The default heltec_v3 build uses native USB CDC-ACM, which requires a
hardware modification to your board. Stock Heltec V3 boards route USB through a
CP2102 bridge chip to UART — the ESP32-S3's native USB pins (GPIO19/GPIO20) are
routed to header pins but not connected to the USB connector.
To enable native USB on a Heltec V3:
- Solder 0-ohm (or 22-ohm) resistors at pads R29 (D+) and R3 (D-)
- Disconnect the CP2102 from the USB connector's D+/D- lines (cut traces or remove the CP2102 bridge resistors)
After this mod, the board appears as /dev/ttyACM0 with the DongLoRa VID:PID
(1209:5741), just like the V4 and nRF boards.
If you have a stock (unmodified) V3, use heltec_v3_uart instead:
just build heltec_v3_uart
just flash heltec_v3_uart
This builds firmware that communicates via the CP2102 bridge (appears as
/dev/ttyUSB0).
Adding a Board
See src/board/PORTING.md.
Protocol
See PROTOCOL.md for the complete wire format specification.