Cyclone 3 and Can bus - Possible?

Altera_Forum · ‎08-10-2009

Hello,

I would like to know if it is possible to build a can bus on my FPGA. I use a Neek II (cyclone 3 starter board : EP3C25F324). This FPGA has no CAN transceiver, but a RS-232 transceiver.

Can I connect the RX and TX signals of the can bus to the RX and TX pins of the RS-232 ? I tried with 2.5V (default) in the planner, the compilation is OK, but my CAN analyzer didn't detect any outputs signals. I think the voltage isn't good.

Is it possible to change the voltage to have something like : high = from 2.75 to 4V and low= from 0.5 to 2.25V ?

I use the "NiosII Advanced CAN IFI" IP to generate the can-bus signals, and the db-9 plug is connected to can-bus analyzer.

Thank you for your help.

Julie

Altera_Forum · ‎08-10-2009

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This FPGA has no CAN transceiver

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But a hardware CAN transceiver is required to interface a CAN bus. Particularly, CAN is a differential bus, so single-ended RS232 can't work.

Altera_Forum · ‎08-10-2009

Hello,

Ok, now I know.

Thank you for the quick reply.

Julie