Lpc2000

Hey Pete, 

Thanks for the reply. In reference to your questions:

> 1. are you configuring the vpbdiv and pll FIRST and then 
configuring 
> the RTC?
Yes I config'ed PLL first, but I skipped the vpbdiv config. I'm 
aware vpbdiv is 0 by default, so I have the uart/timer/rtc 
configured based on (pclk = 1/4 cclk).

> 2. are you enabling the RTC AFTER you have intiialised the fac and 
> int?
Yes. And after trying the values u've calculated (PreInt=0x1C1, 
PreFac=0), the RTC was strangely going twice as fast. (see my 1st & 
2nd first post)
 
> 3. have you tried running with vpbdiv set to 1 (ie resulting in 
> 60mhz opertion (ish).. i am using that for my system without any 
> problem...

Nope...but it's definitely worth a try. I would assume RTC (once 
config'ed) should count correctly regardless of vpbdiv. I'll let u 
know tomorrow how it goes. If u can, try running the RTC with VPBDIV 
= 0 and see what happens. 

Thanks a mil,
Leighton

--- In lpc2000@yahoogroups.com, "Pete" <peterbrown_abroad@y...> 
wrote:
> 
> 
> ok, just been reading your threads....
> 
> for what its worth, and please pardon me if this isnt the solution 
> or you have already considered this... but:
> 
> 
> given your crystal, and the pll & vpbdiv settings I calculated the 
> following:
> 
> YOUR PreInt=0x1C1  and YOUR PreFac = 0.
> 
> Now there is some mention in the databook that preint must be >1, 
> and there is somemention about prefac containing a 0 however i 
didnt 
> really understand what it was on about.... but, im just wondering 
if 
> there is some issue if prefac is 0...
> 
> other questions, which are 'basic' but lets ask and get them out 
the 
> way:
> 
> 1. are you configuring the vpbdiv and pll FIRST and then 
configuring 
> the RTC?
> 2. are you enabling the RTC AFTER you have intiialised the fac and 
> int?
> 3. have you tried running with vpbdiv set to 1 (ie resulting in 
> 60mhz opertion (ish).. i am using that for my system without any 
> problem...
> 
> well, hope this helps. if not then i hope u get it sorted soon!
> 
> kind regards
> pete
> 
> --- In lpc2000@yahoogroups.com, Robert Adsett <subscriptions@a...> 
> wrote:
> > At 09:54 AM 10/6/04 -0700, you wrote:
> > >Yes I have PLLCFG = 0x23 (MSEL=3 PSEL =1). You had any luck 
with 
> > >configuring rtc's?
> > 
> > Actually I haven't worked with them at all (for the kind of 
stuff 
> I 
> > normally do they strike me as a solution looking for a problem, 
> I'd have 
> > rather have had a few more timers [even w/o associated output 
> pins]) but 
> > since you didn't seem to be getting any response I thought I 
might 
> act as a 
> > bit of a sounding board.
> > 
> > I seem to be reading the documentation the same as you so the 
next 
> check 
> > was to check that pclk was what you thought it was (it does seem 
> to be).  I 
> > don't see where your factor of two is coming from either but 
I'll 
> mull it 
> > over a bit more.
> > 
> > Robert
> > 
> > 
> > " 'Freedom' has no meaning of itself.  There are always 
> restrictions,
> > be they legal, genetic, or physical.  If you don't believe me, 
try 
> to
> > chew a radio signal. "
> > 
> >                          Kelvin Throop, III