Cables and power¶
USB connection¶
Use USB 3 throughout: the computer port, cable, adapters, and any hub. Charge-only cables do not work; USB 2 adds latency.
| Computer | Connection to the comma's USB-C port |
|---|---|
| Jetson or Linux PC | USB-A to USB-C, from the computer's USB-A port |
| Mac | USB-C to USB-C |
| iPhone or iPad | Powered USB 3 USB-C hub and data cable; direct USB-C can be unreliable |
| Android | USB-A to USB-C, from a USB 3 hub with USB-C power pass-through |
A USB-C to USB-A adapter with a USB-A to USB-C cable is an alternative for a phone, but does not keep it charging. The comma's USB-C port cannot serve Jetlink and chestnut at the same time.
On a direct cable the comma does not charge an iPhone unless you turn it on:
some iPhones lose the link once the comma powers them. To try it, run
echo -n 1 > /data/params/d/JetlinkChargePhone on the comma and replug the
cable. If the link goes down while the phone charges, the comma stops
charging it until the next plug. A powered hub charges the phone without it.
Connection setting¶
Set Settings > Models > Jetlink while offroad:
- USB: Jetson, Linux PC, Mac, or Android.
- iOS: iPhone or iPad.
Power requirements¶
Power the Jetson and comma separately. The Jetson's supply and cable must deliver at least 25 W and tolerate voltage drops at engine start. Always on or Switched: see the power setup table.
Recommended Jetson power setup¶
Orin Nano Super devkit: a straight 12 V-to-DC barrel adapter on a supply that stays on when the ignition is off (such as an always-on 12 V accessory socket), with Jetson deep sleep enabled.
- Plug: 5.5 mm outer / 2.5 mm inner, center-positive. Check this when buying; the photo shows the style only. Other carrier boards may differ.
- Confirm the socket stays powered after ignition off, including after any delayed shutoff.
- Choose Always on in the installer for deep sleep;
jetlink setupchanges an existing setup.
Parking, starting, and how battery-protection shutdown differs from sleep: Choose your power setup.
Advanced reference¶
TCP testing · Link protocol · Custom USB integrations
From the Jetlink documentation.