# DD3 LoRa Bridge Raspi Debugger

Headless Raspberry Pi Zero W project:
- WiFi client or fallback AP (`serial` / `serialserial`)
- Web portal (`http://192.168.4.1/` in AP mode)
- ESP32 USB serial bridge with live SSE stream and daily log files (`/home/pi/xxx_YYYY-MM-DD_HH-MM-SS.log`)
- Stable symlink to active log (`/home/pi/xxx.log`)
- RTC boot restore + NTP sync + RTC write-back
- Autostart via systemd

## Current State

Current implementation status:
- Boot flow restores system time from RTC (`hwclock -s`) before starting services.
- RTC device auto-detection checks: configured device, `/dev/rtc`, `/dev/rtc0`, `/dev/rtc1`.
- If WLAN is disconnected for ~60s, AP fallback starts on `wlan0`:
  - SSID: `serial`
  - Password: `serialserial`
  - AP IP: `192.168.4.1/24`
  - DHCP range: `192.168.4.10` to `192.168.4.200`
- Web portal is available on port `80`:
  - `/` WiFi scan + connect UI + system actions (reboot/shutdown)
  - `/serial` live serial console (SSE via `/events/serial`)
  - `/api/status` polling is reduced/throttled (15s) for Pi Zero W performance
- ESP32 serial bridge:
  - Auto-detects `/dev/ttyUSB*`, `/dev/ttyACM*`, `/dev/serial/by-id/*`
  - Reconnects automatically on unplug/replug
  - Daily log rollover at midnight with datetime filename
  - No log file is created while no serial device is connected
- Once internet is available, NTP sync runs and writes corrected time back to RTC (`hwclock -w`).
- After boot is ready, power/activity LED is set to 1 Hz blink (`timer`, 500ms on / 500ms off), if LED sysfs control is available.

Note:
- Reboot/shutdown actions in the web UI currently have no authentication. Restrict access to trusted networks only.

Runtime check commands:
```bash
systemctl status serial-bridge
journalctl -u serial-bridge -f
ip a show wlan0
ls -l /home/pi/xxx.log /home/pi/xxx_*.log
sudo hwclock -r
```

## RTC GPIO Wiring (Raspberry Pi Zero W)

Use I2C1 pins on the 40-pin header:

| RTC module pin | Raspberry Pi pin | BCM GPIO | Notes |
|---|---|---|---|
| `VCC` | `Pin 1` | 3V3 | Use 3.3V |
| `GND` | `Pin 6` | GND | Common ground |
| `SDA` | `Pin 3` | GPIO2 (`SDA1`) | I2C data |
| `SCL` | `Pin 5` | GPIO3 (`SCL1`) | I2C clock |

Minimal pin marker (header top):
```text
Pin 1 (3V3)   Pin 2 (5V)
Pin 3 (SDA1)  Pin 4 (5V)
Pin 5 (SCL1)  Pin 6 (GND)
```

Enable I2C + RTC overlay (example DS3231):
```bash
sudo raspi-config nonint do_i2c 0
echo 'dtoverlay=i2c-rtc,ds3231' | sudo tee -a /boot/firmware/config.txt
sudo reboot
```

Verify:
```bash
ls -l /dev/rtc*
sudo i2cdetect -y 1
sudo hwclock -r
```

## Quick install (on Raspberry Pi)

```bash
chmod +x install.sh
sudo ./install.sh
```

Installer behavior:
- First run: full install (apt packages, venv, pip deps, configs, services).
- Re-run/update: fast path, skips apt and pip when not needed.
- `pip install` runs only when `requirements.txt` hash changed (or venv missing).

Optional reboot after first install or low-level config changes:

```bash
sudo reboot
```