Jeff, Cool idea. I am not to the point of needing it today, but it's great to know it exists. Jim -----Original Message----- From: jeffrey.tenney@... [mailto:jeffrey.tenney@...] Sent: Thursday, August 29, 2002 12:44 PM To: 68300@yahoogroups.com Subject: RE: [68300] 68376: CAN bus rate and length issue Jim, My first impression is to go with approach #2 to save cost and development time. You can go with a "hardware" gateway that requires *very* little software and *no* microcontroller. I investigated the Infineon TwinCAN module (SAK 82C900) a while back. It is a standalone controller with *two* CAN interfaces. It has a hardware gateway mode, and it can operate without a host microcontroller if you put some minimal initialization code into a SPI EEPROM. It should be cheap, easy, and have miniscule processing lag during message forwarding. Caveat: We decided not to pursue the TwinCAN in our CAN project so I can't vouch for the TwinCAN. It could be a piece of junk for all I know. Jeff "Godiska, Jim" <jgodiska@...> on 08/28/2002 07:05:05 PM Please respond to 68300@yahoogroups.com To: "'68300@yahoogroups.com'" <68300@yahoogroups.com> cc: Subject: RE: [68300] 68376: CAN bus rate and length issue Jeff, My sincere thanks for your replies. I felt I was going in the right direction, but it is always good to hear confirmation from the experts. Although I was hoping to avoid it, I do have the option to cut my data rate in half (to 500 kHz). At 1 MHz my loading of the bus would be about 15%, with 500 kHz we would be about 30% for a maximum. In the early days, I found that 250 kHz was a definite problem, and I needed something in the 330 kHz range for decent operation. I do have another questions, though. If I would end up needing the 1 MHz data rate and a longer network on a future design, do you have any suggestions as for how to do this? I came up with a couple of ideas, but I do not know how well they would work: 1. Replace the line tranceiver chip with a fiber optic cable network. 2. Make up a repeater module using a microcontroller with 2 CAN bus controller modules to act as a CAN message receiver / buffer / re-transmitter unit. But some of the effective data bandwidth will obviously be limited by the repeater's processing time. Again, thanks for your help, Jeff. Jim -----Original Message----- From: jeffrey.tenney@... [mailto:jeffrey.tenney@...] Sent: Wednesday, August 28, 2002 7:54 PM To: 68300@yahoogroups.com Subject: Re: [68300] 68376: CAN bus rate and length issue Jim, Oops, correction here. Another difference in your choices for TouCAN settings is the sample mode, once per bit or three times per bit. I have no idea why they even put that option into the TouCAN, but my opinion is that it's useless. Pick your sample point (as you've picked 80%) and let the CAN protocol do the rest. Jeff Yahoo! Groups Sponsor ADVERTISEMENT < http://rd.yahoo.com/M=233351.2287382.3722243.2225243/D=egroupweb/S=17065542 <http://rd.yahoo.com/M=233351.2287382.3722243.2225243/D=egroupweb/S=17065542 > 05:HM/A=1212975/R=0/* http://www.gotomypc.com/u/tr/yh/grp/300_mapG/g22lp?Targ <http://www.gotomypc.com/u/tr/yh/grp/300_mapG/g22lp?Targ> et=mm/g22lp.tmpl> --------------------------------------------------- To unsubscribe from this group, send an email to: 68300-unsubscribe@yahoogroups.com To learn more about Motorola Microcontrollers, please visit http://www.motorola.com/mcu <http://www.motorola.com/mcu> < http://www.motorola.com/mcu <http://www.motorola.com/mcu> > Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service < http://docs.yahoo.com/info/terms/ <http://docs.yahoo.com/info/terms/> > . [Non-text portions of this message have been removed] --------------------------------------------------- To unsubscribe from this group, send an email to: 68300-unsubscribe@yahoogroups.com To learn more about Motorola Microcontrollers, please visit http://www.motorola.com/mcu <http://www.motorola.com/mcu> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/ <http://docs.yahoo.com/info/terms/> Yahoo! Groups Sponsor ADVERTISEMENT <http://rd.yahoo.com/M=229441.2311215.3726473.2225242/D=egroupweb/S=17065542 05:HM/A=1189560/R=0/*www.bmgmusic.com/acq/ee/q6/enroll/mhn/10/> --------------------------------------------------- To unsubscribe from this group, send an email to: 68300-unsubscribe@yahoogroups.com To learn more about Motorola Microcontrollers, please visit http://www.motorola.com/mcu <http://www.motorola.com/mcu> Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service <http://docs.yahoo.com/info/terms/> . [Non-text portions of this message have been removed]
Message
RE: [68300] 68376: CAN bus rate and length issue
2002-08-29 by Godiska, Jim