Add SIM7600G-H-M.2 (LTE+GNSS) to BOM

docs/BOM.md

@@ -20,3 +20,32 @@ type: default
 - The mainline kernel driver `peak_usb` is not compiled into the NVIDIA Tegra kernel (JetPack r36.4), so PEAK's proprietary driver is required.
 - Must be built with `NET=NETDEV_SUPPORT` for standard SocketCAN tools (`candump`, `ip link`, etc.).
 - The module lives at `/lib/modules/$(uname -r)/misc/pcan.ko` and is loaded via `modprobe pcan`.
+
+## Waveshare SIM7600G-H-M.2
+
+| Field | Value |
+|-------|-------|
+| **Manufacturer** | Waveshare (SIMCom SIM7600G-H-M.2 module) |
+| **Form factor** | M.2 B KEY |
+| **Purpose** | LTE Cat 4 cellular + multi-constellation GNSS (GPS, Beidou, GLONASS, GALILEO, QZSS) |
+| **Interface** | USB (ttyUSB* for AT commands/NMEA, usb0 for RNDIS Ethernet) |
+| **Power** | 3V – 4.2V (board rail) |
+| **Antennas** | 3× IPEX (LTE main + LTE diversity + GNSS) |
+| **Max data rate** | 150 Mbps DL / 50 Mbps UL (LTE Cat 4) |
+
+### Required software
+
+| Package | Purpose |
+|---------|---------|
+| `gpsd` | Decode NMEA from the GNSS ttyUSB port |
+| `minicom` (or `picocom`) | AT command terminal for module configuration |
+| `dhclient` / `NetworkManager` | Bring up the RNDIS network interface (`usb0`) |
+| `ppp` (optional) | If dial-up (ATD*99#) is preferred over RNDIS |
+
+### Notes
+
+- The module presents multiple USB serial ports (`/dev/ttyUSB0`–`/dev/ttyUSB4`) — typically ttyUSB2 for AT commands, ttyUSB3 for NMEA GPS data.
+- USB PID switching (`AT+CUSBPIDSWITCH=9011,1,1`) may be needed to expose the RNDIS network interface.
+- M.2 B KEY is **not** mechanically compatible with Mini-PCIe.
+- Supply voltage should be ~4.0 V for reliable operation.
+- DO NOT hot-plug while powered.