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AnsweredHot!Configuring ECAN peripheral on a dsPIC33EV @ 60MIPS

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f.stojanovic
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2019/07/09 05:29:55 (permalink)
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Configuring ECAN peripheral on a dsPIC33EV @ 60MIPS

Good afternoon everybody,
 
I hope this thread is posted in the right subforum. If otherwise, I apologize in advance.
 
I am currently attempting to configure the ECAN peripheral on my dsPIC33EV256GM106 on the dsPIC33EV 5V CAN-LIN Starter Kit. My application needs to run @60 MIPS.
 
After reading the Family Reference Manual, the application note AN1249, as well as playing the demo software provided, I've noticed that the only Fcy an ECAN peripheral is ever configured is 40 MHz or less. What's more, the FCAN frequency either equals Fcy or is twice its value (defined by the _CANCKS bit value) and cannot exceed 40 MHz.
 
Does this mean that the ECAN module simply cannot run at, say, 60 or 70 MIPS (i.e. Fosc equaling 120 or 140 MHz )? 
 
Thank you very much, have a nice day.
~Phil
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du00000001
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Re: Configuring ECAN peripheral on a dsPIC33EV @ 60MIPS 2019/07/09 08:33:40 (permalink) ☼ Best Answerby f.stojanovic 2019/07/11 07:29:13
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My guess: the FRMs are from the times when dsPICs maxed out @40 MIPS.
And the CAN LIN Starter Kit might operate at the same 40 MIPS just due to "convenience" (for the developer) issues.
I expect the CAN module to run as well @ 60 or even 120 MHz.
 
Just to mention it: 70 MIPS is (officially) only applicable up to 85 °C !
(Although we already ran the µC at up to 80..85 MIP. Can't recall the temperature - might have not exceeded the 85 °C.)

PEBKAC / EBKAC / POBCAK / PICNIC (eventually see en.wikipedia.org)
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CSA
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Re: Configuring ECAN peripheral on a dsPIC33EV @ 60MIPS 2019/07/10 01:46:08 (permalink) ☄ Helpfulby f.stojanovic 2019/07/11 07:29:10
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I am running two CAN buses on a dspic33ep512mu814 with FCAN of 70 MHz and a BITRATE of 250 KBPS.
Not sure how that compares to your device, but they are in the same family. I don't see that you would have any issues running the CAN bus at the maximum clock speed of the device.
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f.stojanovic
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Re: Configuring ECAN peripheral on a dsPIC33EV @ 60MIPS 2019/07/11 07:28:52 (permalink)
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Hi everyone,
 
Thank you for your replies. Indeed, the module works @60 and 70 MIPS without an issue. That note was addressing the older DSC units which maxed at 40 MIPS.
 
I was able to create a function to automatically configure the registers given a desired baud rate and a bus length in meters. It works flawlessly.
Cheers,
~Phil
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