I2C users, SPRUE27B March2006 clearly states that the I2C module must be operated with a prescaled clock frequency of 7 to 12MHz.
The drivers provided and even recently patched by Ti Try to use a 1 Mhz clock, which will not work. Change psc=2 and you can get it to work at 400Khz (i2c_davinci_busFreq=400) no problem, we have even had it upto 560Khz. Glad to see Ti's driver QA is spot on! (sorry could not resist that dig!) Regards, Andrew On Fri, 2007-08-03 at 10:55 -0400, Arie Muijnck wrote: > The usual - we can do 400kHz, but we tuned it down to 100kHz because of > some slow I2C chips. > The main 'problem' is that a bit-bang driver takes CPU time while the > hardware version should be faster. But with a transfer of 100 us per > byte the overhead of an IRQ driven system is about the same. > > Arie de Muijnck > > -----Original Message----- > From: Andrew Armstrong [mailto:[EMAIL PROTECTED] > Sent: Friday, August 03, 2007 16:37 > To: Arie Muijnck > Cc: Peter Wippich; davinci-linux-open-source@linux.davincidsp.com > Subject: RE: DaVinci I2C Speed > > Arie, > > How fast a bus speed are you getting with your bit-banging driver? > > Regards, > > Andrew > > On Fri, 2007-08-03 at 10:28 -0400, Arie Muijnck wrote: > > We also first tried the standard DaVinci driver. When looking at the > > transfers with an oscilloscope we saw exactly one transfer per 10msec. > > The driver seems to wait for a system tick somewhere. > > > > We just replaced it with a bit-banging driver - 'problem solved' until > > we have time to dig into the DaVinci driver. > > > > Arie de Muijnck > > > > -----Original Message----- > > From: [EMAIL PROTECTED] > > [mailto:[EMAIL PROTECTED] On > > Behalf Of Andrew Armstrong > > Sent: Friday, August 03, 2007 16:18 > > To: Peter Wippich > > Cc: davinci-linux-open-source@linux.davincidsp.com > > Subject: Re: DaVinci I2C Speed > > > > Peter, > > > > That possibly could be a reason for its default, however, I am using > > this on my own hardware which does not use a MSP430. > > > > I have played with the speed and no way does it approach 100 or 400, > 65 > > is the fastest I can get it to run at before it goes nuts. > > > > Regards, > > > > Andrew > > > > > > On Fri, 2007-08-03 at 16:03 +0200, Peter Wippich wrote: > > > Hi Andrew, > > > > > > On Fri, 3 Aug 2007, Andrew Armstrong wrote: > > > > > > > Has anyone else noticed that the DaVinci I2C bus runs at an > > extrememly > > > > slow speed? > > > > > > > > The code appears to acknowledge that it should run faster but it > has > > > > been set to run at only a fraction of its potential? > > > > > > If I remember right this is simply because the MSP on the Dev. Board > > runs > > > a software i2c slave and can not tolerate higher speeds. > > > > > > Ciao, > > > > > > Peter > > > > > > _______________________________________________ > > > Davinci-linux-open-source mailing list > > > Davinci-linux-open-source@linux.davincidsp.com > > > > http://linux.davincidsp.com/mailman/listinfo/davinci-linux-open-source > > > > _______________________________________________ > > Davinci-linux-open-source mailing list > > Davinci-linux-open-source@linux.davincidsp.com > > http://linux.davincidsp.com/mailman/listinfo/davinci-linux-open-source > > > > -------------------------------------------------------- > > > > > > CONFIDENTIALITY NOTICE - This e-mail transmission, and any documents, > files or previous e-mail messages attached to it may contain information > that is confidential or legally privileged. If you are not the intended > recipient, or a person responsible for delivering it to the intended > recipient, you are hereby notified that you must not read this > transmission and that any disclosure, copying, printing, distribution or > use of any of the information contained in or attached to this > transmission is STRICTLY PROHIBITED. If you have received this > transmission in error, please immediately notify Arie Muijnck by > telephone or [EMAIL PROTECTED] and delete the original > transmission and its attachments without reading or saving in any > manner. > > _______________________________________________ > > Davinci-linux-open-source mailing list > > Davinci-linux-open-source@linux.davincidsp.com > > http://linux.davincidsp.com/mailman/listinfo/davinci-linux-open-source > > -------------------------------------------------------- > > > CONFIDENTIALITY NOTICE - This e-mail transmission, and any documents, files > or previous e-mail messages attached to it may contain information that is > confidential or legally privileged. If you are not the intended recipient, or > a person responsible for delivering it to the intended recipient, you are > hereby notified that you must not read this transmission and that any > disclosure, copying, printing, distribution or use of any of the information > contained in or attached to this transmission is STRICTLY PROHIBITED. If you > have received this transmission in error, please immediately notify Arie > Muijnck by telephone or [EMAIL PROTECTED] and delete the original > transmission and its attachments without reading or saving in any manner. > _______________________________________________ > Davinci-linux-open-source mailing list > Davinci-linux-open-source@linux.davincidsp.com > http://linux.davincidsp.com/mailman/listinfo/davinci-linux-open-source _______________________________________________ Davinci-linux-open-source mailing list Davinci-linux-open-source@linux.davincidsp.com http://linux.davincidsp.com/mailman/listinfo/davinci-linux-open-source
