Car Diagnostics Device

A car diagnostics device, also known as an OBD-II (On-Board Diagnostics II) scanner or car diagnostic tool, is a device used to communicate with a vehicle’s computer system to access information and diagnostic codes stored in the vehicle’s onboard computer.

These devices can read and interpret error codes generated by various vehicle systems, including the engine, transmission, brakes and emissions control systems. They can also provide real-time data on engine performance, fuel efficiency and other parameters, allowing users to monitor the health and performance of their vehicle. There are many car diagnostics devices, especially those that interface with OBD-II ports and utilize UART interface to update its firmware.

FTDI products can be integrated into a car diagnostics device to communicate with a PC or laptop for firmware updating. The example below uses FTDI’s FT230XQ USB to UART IC which has the following key features, making it an ideal candidate for a car diagnostics device:

    • Single chip USB to asynchronous serial data transfer interface.
    • Entire USB protocol handled on the chip. No USB specific firmware programming required.
    • Fully integrated 2048 byte EEPROM for storing device descriptors.
    • Data transfer rates from 300 baud to 3 Mbaud.
    • 512 byte receive buffer and 512 byte transmit buffer utilizing buffer smoothing technology to allow for high data throughput.
    • FTDI’s royalty-free Virtual Com Port (VCP) and Direct (D2XX) drivers eliminate the requirement for USB driver development in most cases.
    • Transmit and receive LED drive signals.
    • UART interface support for 7 or 8 data bits, 1 or 2 stop bits and odd / even / mark / space / no parity.
    • Integrated +3.3V level converter for USB I/O.
    • Configurable I/O pin output drive strength.
    • Integrated power-on-reset circuit.
    • UART signal inversion option.
    • Internal 3.3V / 1.8V LDO regulators.
    • Low operating current of 8mA (typical) and USB suspend current of 125uA (typical) current.
    • Low USB bandwidth consumption.
    • UHCI / OHCI / EHCI host controller compatible.
    • USB 2.0 Full Speed compatible.
    • Extended operating temperature range: -40°C to 85°C.
    • Available in compact Pb-free 16 Pin SSOP and QFN packages (both RoHS compliant).


The block diagram shows at a high level how FTDI’s FT230XQ can be integrated into a car diagnostics device.


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