mikkeli
ba9fefb5d2
In the car with ignition on, the listen-only probe found 500 kbps (2673 frames in 3 s, zero RX errors; nothing at other rates). The OBD port isn't gatewayed: 27 periodic IDs, ~893 frames/s. A udev rule now starts can-up@can_pcan on boot and hot-plug with 500k and listen-only, to be dropped when obd-poller becomes the single writer. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
4.8 KiB
4.8 KiB
type
| type |
|---|
| reference |
Bill of Materials
PEAK-System PCAN-USB
| Field | Value |
|---|---|
| Manufacturer | PEAK-System Technik GmbH |
| Model | PCAN-USB |
| USB ID | 0c72:000c |
| Purpose | USB-to-CAN adapter for reading car CAN bus traffic |
| Interface | SocketCAN netdev |
| Bitrate | 500 kbps, measured on the Z27AG OBD port (listen-only by default; see CAN bitrate plan) |
| Driver | PEAK proprietary driver 9.2.0 (netdev build) — out-of-tree module, must be rebuilt after kernel updates |
Notes
- The mainline kernel driver
peak_usbis not compiled into the NVIDIA Tegra kernel (JetPack r36.4), so PEAK's proprietary driver is required. - Must be built with
NET=NETDEV_SUPPORTfor standard SocketCAN tools (candump,ip link, etc.). - The module lives at
/lib/modules/$(uname -r)/misc/pcan.koand is loaded viamodprobe pcan. - Jetson Orin Nano has a built-in CAN controller (exposed by GPIO pins). Kernel
canNorder is not stable, so both are pinned by udev: onboard →can_onboard, PCAN-USB →can_pcan(device naming).
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, QMI cdc-wdm0 + wwan0 for data) |
| 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 |
ModemManager + NetworkManager |
Manage the modem and the LTE data connection (QMI) |
qmi_wwan + cdc-wdm kernel modules |
Not in the Tegra kernel; built out of tree in ~/infra/qmi_wwan/ |
minicom (or picocom) |
AT command terminal for module configuration |
Notes
- The module presents multiple USB serial ports (
/dev/ttyUSB0–/dev/ttyUSB4) — ttyUSB2/3 for AT commands, ttyUSB1 for NMEA GPS data (symlinked as/dev/sim7600-gps). - Default USB composition (PID 9001) is used with QMI; no PID switch needed. PPP dial-up does not work with the povo SIM (network detaches).
- Setup details: SIM7600 setup report.
- 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.
RTC backup battery
Status: optional, low priority. Battery choice settled (CR2032); footprint/R560 still to verify against NVIDIA's schematic.
| Field | Value |
|---|---|
| Purpose | Keep the RTC (rtc0, nvvrs-pseq-rtc) running while the board is unpowered, so the clock is correct at boot without network or GPS |
| Carrier board | P3768 (Orin Nano Developer Kit): pads present, connector not populated (needs soldering) |
| Connector (per NVIDIA docs, as quoted on the forum) | Wieson AC2651-0011-003-HH, 2-pin, 1.25 mm pitch. A community-used substitute is Molex 53398-0271 header + 51021-0200 housing |
| Battery | CR2032 (primary 3 V lithium) in a holder with leads. Not ML2032 or other rechargeables: the module datasheet says the backup pin (PMIC_BBAT) does not support charging, so a rechargeable just drains, and it has ~⅓ of the capacity |
| Expected life | RTC draws 12–50 µA while unpowered (~15 µA measured on the forum) → CR2032 (~220 mAh) lasts ~1.5–2 years typical, ~6 months worst case. Drains only while the board has no power |
| Extra parts | Forum reports also populating R560 (0.56 Ω, e.g. Panasonic ERJ2BQFR56X); confirm in the P3768 schematic |
Notes
- Without it the clock boots at a stale date (seen 2026-10-08: June 4) until NTP syncs. See the time sync report.
- Forum sources: RTC battery on Orin Nano DevKit, How to add RTC battery.
- A reported side effect: the battery lead and socket make the case cover sit unevenly.
- Polarity: one forum post says the positive pad is marked with a white triangle. Confirm with a meter before connecting.
- Test after fitting: power off fully, wait a few minutes, boot with no network, and check
cat /sys/class/rtc/rtc0/date(should be today, not a reset date). - Low priority: online almost always means NTP within a minute; the gap only matters for offline drives (see the time sync report).