Root cause: XPowersAXP2101(Wire) constructor defaults to SDA=8, SCL=9
(from generic esp32s3 variant pins_arduino.h). Its begin() method then
calls Wire.begin(8, 9), overriding our Wire.begin(3, 2). All I2C
traffic went to the wrong GPIO pins.
Fix: pass explicit I2C_SDA, I2C_SCL to the XPowersAXP2101 constructor
so it uses GPIO 3/2 (the T-Watch Ultra's actual I2C pins).
Also removed I2C diagnostic/recovery code that was debugging the
wrong problem.
Standalone GPS beacon mode: when no KISS host is connected for 15s,
the RNode transmits position and battery telemetry over LoRa.
Two beacon paths:
- LXMF (recommended): encrypted per-packet messages with announces,
compatible with Sideband and any LXMF application. Supports IFAC
network authentication.
- Legacy JSON: plaintext or encrypted raw packets for simple collectors.
Key changes:
- GPS support for T-Beam Supreme S3 (L76K) and Heltec V4 (external)
- SX1262 radio fixes: IQ polarity, DCD preamble lockup, RX reliability
- LXMF identity management with NVS-backed Ed25519/X25519 keys
- IFAC authentication (CMD_IFAC_KEY 0x89) for private networks
- Per-channel serial isolation (USB, BLE, WiFi)
- GPS status page in OLED display rotation
- Provisioning via rnlog: provision-lxmf, provision-ifac
- Documentation in Documentation/BEACON.md
// there are three version of V3: V3, V3.1, and V3.2
// V3 and V3.1 have a pull up on pin_ctrl and are active low
// V3.2 has a transistor and active high
// put the pin input mode and read it. if it's high, we have V3 or V3.1
// other wise, it's a V3.2
Also, changed the min, max, float values for V3 boards. From what I can see, most are sold with
a battery like this: https://www.amazon.com/dp/B0D3LMQSGL
These batteries advertise a min voltage of 3 and max of 4. Float should be a tiny bit below Max.
