I have an i.MX6UL dev board, booted, set up, all good.
Connecting CAN1H with CAN2H and CAN2L with CAN2L i can cansend/candump my CAN frames just fine, eg. what I send out on one CAN bus I can receive on the other. The connection is just two wires on the CAN connector J1202.
Now I'd like to send real CAN messages from another device to the dev board. Therefore I have set up two Arduino nanos, each equipped with an mcp2515 CAN transceiver. Sending frames from one to the other works just fine.
Sending frames from one Arduino/mcp2515 combo to the dev board does not work, no messages come through.
Serial parameters are set and fixed to 125kbps on all devices. I suspect wrong logic levels as my oscilloscope shows me vastly different levels (ie. in the two-digit millivolt range on the dev board)...
Do I need an external transceiver for the dev board?