Max32 CAN Clock Oscillator Frequency

Created Mon, 13 May 2013 02:12:52 +0000 by SkierHiker

SkierHiker

Mon, 13 May 2013 02:12:52 +0000

Can someone tell me the correct oscillator frequency to use in the CAN Bit Rate Calculator for the Max32? I'm guessing it is either 8 or 16 mhz but not sure which one.

Also, does the Max32 use the MCP2510 CAN controller?

The two calculators I'm using are:

[url]http://www.kvaser.com/en/support/bit-timing-calculator.html[/url] [url]http://www.intrepidcs.com/support/mbtime.htm[/url]

Thanks - Mark.

dangeljs

Tue, 14 May 2013 01:31:52 +0000

The CAN datasheet for the chip is your best answer: http://ww1.microchip.com/downloads/en/DeviceDoc/61154C.pdf

The Chipkit boards run at 80MHz, and it has an on-board CAN controller inside the chip. So a transceiver is needed for the physical connections to connect to the bus.

Page 85 of the datasheet gives an example of setting up the bit timing with an 80MHz system clock.

Good Luck,

Jason

unexpectedly

Tue, 03 Feb 2015 21:28:15 +0000

That datasheet isn't very clear; the one working example is all magic numbers.

An online bit calculator got me close and thankfully, there's a downloadable calculator for anyone whose CAN bus isn't 1M.

The calculator worked for my 500k CAN-bus. Looking back at page 85, I don't see how I could come up with Propagation=3, Phase 1=8, Phase 2=8, Jump Width=1.

pedrodova

Mon, 06 Apr 2015 17:10:54 +0000

SkierHiker, the datasheet doesn’t go into the details and give an overview of the application for this IC. They will provide you with a general application note which can give you an idea but you can’t replicate that as is in a professionally developed circuit. Since I’m guessing that your CAN bus runs at more than 16Mhz, I think it’ll be best if you can try to have idea from the provided datasheet.