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Using CANBUS with your car

Topic last updated 11 May 2012, by Travis G. 1 reply
Gregor Mendel
11 May 2012

I drive a 2007 Toyota RAV-4. It is OBD-II compliant and uses CAN. I have an NXP LPC1768 mBed and I was wondering if I would need any extra hardware (besides level conversion circuitry) to communicate, as the 1768 has CAN support built in. I'd rather not have to buy an extra piece of hardware if I don't have to.

Thanks.

Travis G
11 May 2012

I'm using a CAN Tranceiver, 12V to 5V regulator, support passives and the MBED for CAN communication. I'm using an MCP2551 and 10uF capacitor for the CAN stuff, and TL750M05CKCSE3 (IC LDO REG POS-VOLT 5V TO220-3) and a few 10uF caps and a 1n4004 diode for the regulator. You don't need a termination resistor, as it's built into the OBD-II port on vehicles (i.e. any OBD-II readers don't have term resistors).

I'm using this board (but you could use JUST the CAN and regulator part. http://mbed.org/media/uploads/WiredHome/mbed_breakout_board_sch_v0.05.pdf

The tranceiver is only 5V, but since the OBD connector has 12V, might as well power the MBED and Tranceiver with it.