feat: add moonshine_NRF52_ebyte variant (Ebyte nRF52840 + E22-400M33S)

DIY Meshtastic node using an Ebyte nRF52840 MCU module with LFXO crystal and E22-400M33S LoRa module (SX1268, 433MHz, 33dBm). Pin assignments: - LED (LED_PAIRING): P0.15, LED_LORA DIO1: P1.10, BUSY: P0.28 (AIN4) - LORA_CS: P0.17, RESET: P1.13, RXEN: P1.09, SPI: P0.20/P0.22/P1.00 - VBAT_ADC: P0.03 (0.5 divider), CHAG_DET: P0.13, BUZZER: P1.11 - BUTTON: P0.24, I2C: SDA=P0.08/SCL=P0.04 (wired, no devices) PA parameters derived from E22-M UserManual V1.2 power curve (not from E22-900M33S which uses a different PA with 25dB gain): - SX126X_MAX_POWER=21, TX_GAIN_LORA=12 (chip 21dBm -> module ~33.5dBm) - DIO2_AS_RF_SWITCH with MCU-controlled RXEN, TCXO 1.8V (TCXO_OPTIONAL) USB CDC serial enabled by default (nRF52840 built-in). No GPS/screen/ I2C devices. Uses S140 v6 SoftDevice (matches nice!nano bootloader). Flashable via USB (1200bps touch DFU) or UF2 drag-and-drop.
2026-07-27 17:48:01 +08:00
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+# Moonshine NRF52 ebyte
+
+DIY Meshtastic node variant based on an Ebyte nRF52840 MCU module and E22-400M33S LoRa module.
+
+## Hardware
+
+- **MCU module**: Ebyte nRF52840 (512 KB flash / 128 KB RAM)
+- **LF clock**: 32.768 kHz crystal (`USE_LFXO`)
+- **LoRa**: E22-400M33S (SX1268 + 33dBm PA, 2W, 433MHz) - `SX126X_MAX_POWER=8`,
+  `TX_GAIN_LORA=25`. `SX126X_RXEN` (P1.09) is MCU-controlled by RadioLib; TXEN is
+  driven by DIO2 (`SX126X_DIO2_AS_RF_SWITCH`). TCXO voltage 1.8V with `TCXO_OPTIONAL`
+  fallback to XTAL.
+- **LED**: Bluetooth pairing status on P0.15 (`LED_PAIRING`). Solid on = BLE
+  connected, slow blink = unpaired, fast blink = pairing, off after 30s idle.
+- **Battery ADC**: 0.5 voltage divider (equal resistors)
+- **USB CDC serial**: enabled by default (nRF52840 built-in USB-ACM). Debug output
+  and Meshtastic CLI communication go through the USB serial port.
+- **I2C**: SDA/SCL pins wired (P0.08/P0.04) but no I2C devices connected.
+
+## Pin map
+
+| Function      | Pin   | Notes                              |
+| ------------- | ----- | ---------------------------------- |
+| LED           | P0.15 | Bluetooth pairing status           |
+| CHARGE_DET    | P0.13 | Active high (charging)             |
+| BUTTON        | P0.24 | User button                        |
+| BUZZER        | P1.11 | PWM buzzer                         |
+| BATTERY_ADC   | P0.03 | AIN1, 0.5 divider                  |
+| IIC_SDA       | P0.08 | Wired, no device                   |
+| IIC_SCL       | P0.04 | Wired, no device                   |
+| SPI_MISO      | P1.00 |                                    |
+| SPI_MOSI      | P0.22 |                                    |
+| SPI_SCK       | P0.20 |                                    |
+| LORA_CS       | P0.17 |                                    |
+| LORA_DIO1     | P1.10 | IRQ                                |
+| LORA_BUSY     | P0.28 | AIN4 (AI4)                         |
+| LORA_RESET    | P1.13 |                                    |
+| LORA_RXEN     | P1.09 | MCU-controlled RXEN; TXEN via DIO2 |
+
+## Build & Flash
+
+### Build
+
+```sh
+pio run -e moonshine_NRF52_ebyte
+```
+
+Uses `PRIVATE_HW` (HardwareModel 255) - no protobuf or `architecture.h` changes
+required.
+
+The build links against `nrf52840_s140_v6.ld`, so the application is linked to
+start at `0x26000` and requires the S140 SoftDevice v6.x to be present on the
+chip at `0x0`-`0x25FFF`. The build output (`firmware-*.hex` / `.uf2`) contains
+**only the application**, not the SoftDevice.
+
+### Flash via USB (nice!nano)
+
+The nice!nano comes pre-flashed with the S140 v6 SoftDevice and the Adafruit
+UF2 bootloader. No SWD probe is needed - firmware can be uploaded over USB.
+
+**Method 1: PlatformIO serial DFU (recommended)**
+
+```sh
+pio run -e moonshine_NRF52_ebyte -t upload
+```
+
+PlatformIO opens the USB CDC serial port at 1200 baud to trigger the DFU
+bootloader, then uploads via `nrfutil` serial DFU. The board automatically
+resets into the application after upload.
+
+**Method 2: UF2 drag-and-drop**
+
+1. Double-tap the Reset button to enter UF2 bootloader mode. A USB mass storage
+   volume will appear (e.g. `NRF52BOOT`).
+2. Copy the `.uf2` file from `.pio/build/moonshine_NRF52_ebyte/firmware-*.uf2`
+   to the USB volume.
+3. The board automatically resets into the application after the file transfer
+   completes.
+
+### Flash via SWD (alternative)
+
+If the SoftDevice or bootloader is missing or corrupted, flash via SWD with
+OpenOCD (CMSIS-DAP / J-Link / ST-Link):
+
+```sh
+# Full flow: recover (erase all + unlock) -> SoftDevice -> app -> reset
+openocd -f interface/cmsis-dap.cfg -f target/nrf52.cfg \
+  -c "init; nrf52_recover; \
+      program bin/s140_nrf52_7.3.0_softdevice.hex verify; \
+      program .pio/build/moonshine_NRF52_ebyte/firmware-*.hex verify; \
+      reset run; exit"
+```
+
+When the SoftDevice is already on the chip and only the application changed,
+skip `nrf52_recover` and the SoftDevice line:
+
+```sh
+openocd -f interface/cmsis-dap.cfg -f target/nrf52.cfg \
+  -c "init; \
+      program .pio/build/moonshine_NRF52_ebyte/firmware-*.hex verify; \
+      reset run; exit"
+```
+
+## Notes
+
+- The firmware hex filename contains a commit hash (e.g. `2.8.0.421838f`); use
+  the actual file produced by `pio run` or a shell glob.
+- USB CDC serial is available immediately after boot for debug output and the
+  Meshtastic Python CLI (`meshtastic --noproto` / `meshtastic --info`).
+- `MESHTASTIC_EXCLUDE_I2C=1` is set because no I2C devices are connected. Remove
+  this flag from `platformio.ini` if an I2C display or sensor is added later.
+- No GPS, screen, accelerometer, or magnetometer is configured. Remove the
+  corresponding `MESHTASTIC_EXCLUDE_*` flags from `platformio.ini` if hardware
+  is added.