brettrd/canadapter

A CANbus adapter for FPGA dev boards

CANadapter

This is a basic CAN bus adapter based on the MCP2515 and the MCP2551. The design is largely compatible with the Sparkfun CAN-BUS Shield for the sake of everyone's sanity.

The connectors are intended to be pin-compatible with Pmod, but there doesn't seen to be a standard or even defacto pinout for CANbus on Pmod online.

Board images generated by gerblook.org

##Major design goals:

• Full electrical isolation
• Hardy CAN front-end
• Support CAN bus development on the FPGA driven icoBoard.

Parts List:

CAN interface:

• 1x MCP2551 soic8 - CAN interface chip
• 1x PESD1CAN sot23 - TVS diode
• 2x TLP2361 fast optocoupler - optoisolation
• 2x 60R 1210 resistor - termination resistors
• 1x 4.7nF 1206 capacitor - Common mode filter
• 1x 1uF 1206 capacitor
• 1x 100R 0603 resistor
• 1x 330R 0603 resistor
• 1x 4K7 0603 resistor
• 1x 4pin header

CAN Controller:

• 1x MCP2515 soic18 7.5mm - CAN controller IC
• 1x 16MHz 5032 crystal
• 1x 1uF 1206 capacitor
• 2x 18pF 0603 capacitor
• 1x 2x6pin header

canadapter's Issues

Voltage 3.3V < 5V

MCP2551 transciever is for 5V operation while
PMOD power is 3.3V

I'd suggest to replace 2551 with a different
3.3V compliant transciever, usually they are
SMD don't know of any DIL pacage with 3.3V

Choose an optocoupler

The optoisolator in the schematic is just a place-holder.