Q: Can I use the CAN drivers at low speeds?
Yes. The 82527 CAN chip and 82C250 transceiver support bus speeds from 1Mbps all the way down to 5kbps.
Q: How can I calculate the values needed for different CAN bus speeds?
We have a number of baud rate settings pre-defined in our CE CAN sample code(see ClientDlg.cpp). If you have a rate that's different from those, you can calculate the baud rate and SP(sample point) yourself. The 82C527 data sheet has information about how to set the values for Bit Timing Registers 0 and 1. Alternatively, you can use the Windows application from www.kvaser.com (Developer, Downloads -> Software Tools, General utility programs -> Bit timing register calculator for 82c200, 82527, and compatibles) to calculate the values. We recommend using a SP between 60 and 70%.
For example, for 83.3kbps you could set BTR0 to 0xC3 and BTR1 to 0x7E (this gives SP=67%).
For further links and information about CAN on ADS products, please consult the CAN bus topic index.
Edited by akidder 20-Nov-2003: Updated Kvaser site path for locating bit timing calculator (from "Downloads -> Driver routines and programs -> Bit timing register calculator, b82c200.zip") |
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Posted - 17 Apr 2003 : 14:38:30
