Lpc2000

Olaf,

I've tried to calculate my own bit timing values for the 14.745 MHz crystal
but they are a bit out on the actual baud rate.

125k baud: I got 0x001C001E (for the LPC's CANBTR register) that's a BRP of
30 but that gives 122.875k baud. Is this tolerable?

250k baud: I got 0x001C000F (again for the LPC's CANBTR register) giving a
BRP of 15 that gives 245.750k baud. Again is this tolerable.

I haven't tried it for any other baud rates. I'll try higher ones to see if
the level of error is reduced.

Regards
Pauric

-----Original Message-----
From: Tutors of ESAcademy [mailto:esacademy@...]
Sent: 20 July 2004 08:44
To: lpc2000@yahoogroups.com
Subject: [lpc2000] Re: CAN bit timing with 14.745 MHz crystal frequency


--- In lpc2000@yahoogroups.com, Pauric Doherty <pauric_doherty@y...>
wrote:
> Does anybody have a CAN bit timing value for a 14.745 MHz crystal.
The new
> CAN_All sample from philips_apps is designed for a 12 MHz crystal.
>
> Is there a CAN bit rate calculator developed for ARM systems yet.
I've seen
> calculators for 8-bit CAN controllers.


Hi Pauric,

We don't have a CAN bit rate calculator for the LPC2xxx readily
available, but if it is just one rate we can help you calculate it...

Which rate do you need? Pls. note that 14.745 might limit your
choices in available bit rates...

Olaf

Tutor at ESAcademy
www.esacademy.com
www.canopen.com






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