CAN Communication Issue

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CAN Communication Issue

Post  lyh8 on Fri Apr 23, 2010 4:32 pm

Hello Sir,

I tried to run TI F2808 eCAN example code to exercise CAN communication on the dsp. I also use National Instrument's Bus Monitor tool associated with their USB-8473 CAN card to monitor the communication. I set both side to be 125kbps. When I ran the example code, the oscillosope showed data on the bus, however, there were no data shown in the Bus Monitor tool. Do you any clue what could be wrong?

lyh8

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Re: CAN Communication Issue

Post  lzmind on Fri Apr 23, 2010 5:13 pm

To make CAN communication successfully, you must make right the following three things.

1. Each end of the CAN bus must have a 120 ohm termination resistor.
2. Each node must run at the same baud rate. Use your scope to measure the bit width of the data sent from your target. As your baud rate is 250 kbps, the bit width should be 8 us, because 1/8us = 125 kbps.
3. The sampling point of each node should be similar, for example, all nodes are sampled at 80% point.

Hope that helps.

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Re: CAN Communication Issue

Post  lyh8 on Fri Apr 23, 2010 11:53 pm

Thank you for your advice. It was true that my target baud rate was not 125 kbps, I had wrong BRP setting that I thought it was. Now the data are shown in Bus Monitor window.

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