PRODUCTS & TECHNOLOGY
Analog IC Enables Automotive ODB-II Remote Diagnostics from Cell Phones
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A new automotive integrated circuit is an ODB-II Diagnostics Interface/Controller. The JV700 from JVD Semiconductors is a custom Analog ASIC that resides in a small dongle that plugs into the vehicle’s ODB-II connector (typically located under the dash). The JV700 incorporates all the critical analog functions required to interface and communicate through the ODB-II connector with all major automotive buses. The chip receives instructions to configure a complex array of low RDS(on) MOSFET switches that properly align the chip’s five bus transceivers to the correct ODB-II pins based on the vehicle’s make, model, year and VIN. The JV700 then communicates the vehicle information via a serial bus to a nearby microcontroller where the data is processed and communicated via Bluetooth to a cell phone or mobile computer for viewing.
Diagnostic Trouble Codes (DTCs) are how ODB-II identifies and communicates to technicians where and what onboard problems exist. The first number in the DTC indicates whether the code is an SAE generic code (applies to all ODB-II systems) or is specific to the vehicle manufacturer. The remaining three numbers provide information regarding the specific vehicle system and circuit.
While these communication protocol standards are universal, not every make and model uses the same pins on the ODB-II connector to access the information, making universal diagnosis all but impossible without the circuitry found in the JV700.
To further complicate diagnostic testing, there remain several pins in the ODB-II connector that are unspecified and their use is left to the vehicle manufacturer’s discretion. These unassigned pins are available for use by the manufacturer for things such as airbags, alarms, remotes and more, and their use varies widely among the world’s car manufacturers and even among different models produced by a single manufacturer. The JV700 can connect and communicate with the unassigned pins to read and manage the peripheral information as well.
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