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16- vs 32-bit CAN filter efficiency

Question asked by Charles Miller on Sep 1, 2016
Latest reply on Sep 2, 2016 by Charles Miller
Is there a benefit to using 16-bit filters versus 32-bit filters in terms of MCU efficiency?  I am writing a driver for DeviceNet CAN, and the only frames I expect have standard (11-bit) identifiers, not extended.  For this, 16-bit filters seem just fine, as a have don't-cares for the EXID[17:15] bits.  With 32-bit filters, I would extend the don't cares to all EXID bits.

The question is: is it less desirable to use don't-cares for 18 EXID bits versus 3 bits (for 16-bit filters)?   Factors could include filtering speed, delay, processor resource, power, etc.  I just don't know enough about the internal network processing implementation to make a judgement.  (Or even know if it really matters in the long-run...)

Thanks, all.

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