Lpc2000

--- In lpc2000@yahoogroups.com, Robert Adsett <subscriptions@a...> 
wrote:

> >PLLCFG = 0x61 (P=3, M=1): 577ns (should be 14.7Mhz but is 29Mhz)
> 
> Ah, I see what's happening,  I should have clued in earlier
> 
> PlLLCFG of 61 gives PSEL of 3, MSEL of 1
> 
> That gives a P of 8 and and M of 2

Call me embarrassed!  Thanks everyone for your help on this.  I 
totally missed the lookup tables that translate the bits for the P 
and M values.  Things make much more sense now!  

The CrossWorks startup code contains these lines:

  /* Configure PLL Multiplier/Divider */
  mov r1, #0x24 /* multipler = 4, divider = 1 */

I both assumed the values were chosen for a 14.7 Mhz crystal as this 
is the frequency found on most demo boards (for serial port reasons) 
and I also read the comment as M = 4 and P = 1.  In reality, those 
are just the raw bit values MSEL and PSEL and they get translated 
into M = 5 and P = 2 by the magic tables.

I and others still seem to be stuck with the flash loading problem, 
but at least the PLL is working right now!  Progress!

Thanks again to all.