CAN Shield RX blinking but no data


I’m interfacing to a CAN Bus running at 250kBaud and am just using the sample read program with the speed changed to 250. I can see the data coming through with my CAN analyzer hooked to my laptop but the shield is not picking up the data. The rx light will blink but the MSG_Recieved flag is not tripping.

Any ideas?

Also since I’m attaching to a terminated bus, should I break off the resistor by the screw down plug?

Any help would be greatly appreciated!

Just a note on the messages:

As a ref, one of the messages is an extended frame with this detail:
Rate: 250.000 kBaud
Length: 8
Data 00 00 00 00 00 00 00 00

These packets come at a rate of 1 per second and there are other packets on the bus being sent in close proximity (.0006) seconds after.

Got it working. Had to set up a filter and mask.

What version of the library were your using?

I was using what was on the site at that time. I think the buffer was moving too slow without a mask as there were a few messages firing in very close proximity.

Looking at the GitHub history, it looks like the filters were initialized with the extended ID flag raised which would have prevented standard IDs from being received. This might have been the cause if the library was old enough. This has been fixed since May 22, 2013.


I’m using the CAN Bus shield and I would only like to send a single message. When I run a program it will spam hundreds of messages per second even if I only call sendMsgBuf a single time.

Any ideas?

Tell me about your setup. It sounds as if you only have one active CAN device on your bus. Per CAN specification, a controller will resend a message till it receives an acknowledge from another controller on the bus.

Can you tell me how did you setup the filter and mask.
I am having the exact same issue