Hardware

What WiCAN OBD is made of: the OBD-II plug and the pins it uses, where its power comes from, the USB port on the back, the three LEDs and the CAN controller behind them.

The OBD-II plug

WiCAN OBD plugs into the car's OBD-II socket (SAE J1962) and uses four of the sixteen pins: the battery on 16, ground on 5, and the high-speed CAN bus on 6 and 14. The Pinout page has the drawing and the table.

Power

WiCAN runs from the car's battery as long as it is plugged in, whether the ignition is on or not. A parked car therefore keeps feeding it, which is what sleep mode is for: below a battery voltage you choose, WiCAN goes to sleep and draws under 1 mA, and it wakes when the engine charges the battery again. See Sleep and battery alert.

The voltage on the Status tab is measured on pin 16. With the engine off a healthy battery reads 12.4 to 12.8 V; with the engine running the alternator lifts it to about 13.5 to 14.8 V.

The USB port

The micro USB port is for flashing and recovery: it powers the board enough to flash a firmware over the cable, see Recovery over USB. It is not meant to power WiCAN in use, and WiCAN OBD does not act as a USB CAN adapter; that is WiCAN USB.

The LEDs

Three LEDs on the face of the case: power, WiFi and data. LEDs says what each one means.

The CAN controller

Frames

CAN 2.0A (11-bit ids) and CAN 2.0B (29-bit ids), data and remote frames

Bit rates

5, 10, 20, 25, 50, 100, 125, 250, 500, 800 and 1000 kbit/s, chosen under Settings › CAN

Modes

Normal, or Silent for listening only: WiCAN then never transmits, not even the acknowledge bit, so it cannot disturb the bus

Bus speed of a car

500 kbit/s on the OBD port of almost every car; 250 kbit/s on some, and on trucks

Hardware versions

The About tab shows the hardware as WiCAN-OBD. Units sold since mid 2022 are hardware version 3 (the board reads Wi-CAN v310); they measure the battery voltage and have sleep mode. The first units, hardware version 2.10, have neither: their Status tab shows no usable voltage and sleep mode stays off whatever the setting. Both run the same obd firmware image.