Lpc2000

Ok then...forgot about the divider value. Well, I tried out what u said too. I expect it to work but apparently the PLL's still not locking...Any ideas?
 
Uwe Arends <Uwe_Arends@...> wrote:
Leighton,

from the user manual, the CCO clock has to be in the range from 156 to 320MHz.
It is calculated as M*Fosc * 2 * P with M being PLLCFG[4:0] + 1 and P being
one of 1, 2, 4, 8 for the four different values possible for PLLCFG[6:5].

Your setting of PLLCFG would cause it to run at 4*14.7456MHz * 2 * 1 == 117.96MHz,
just outside the allowed range. Set P to 2 and you should be ok => PLLCFG = 0x23.

hth
-uwe
----- Original Message ----- 
From: "Leighton Rowe" <leightonsrowe@...>
To: <lpc2000@yahoogroups.com>
Sent: Tuesday, August 24, 2004 10:54 PM
Subject: [lpc2000] PLL not locking


> I'm working on a custom 2114 board (using a 14.7456 MHz crystal) and 
> I'm noticing something weird going on with the PLL.
> 
> PLLCFG = 0x03;                  //PLL Multiplier = 4 (58.98 MHz0
> PLLCON = 1;                     // PLL Enable
> 
> PLLFEED = 0xAA;
> PLLFEED = 0x55;                         
> 
> while(!(PLLSTAT & 0x0400));     //Wait until PLL is locked
>   
> PLLCON = 3;                           // Connect PLL clock
> PLLFEED = 0xAA;                         
> PLLFEED = 0x55;  
> 
> Apparently the PLL isn't locking, causing the processor to basically 
> wait forever. 
> 
> This code works fine with the mcb2100 @ 12.Mhz (Multiplier = 5). But 
> I have no clue as to why the the PLL isn't locking @ 14.74 MHz after 
> I set up the registers. 
> 
> Anyone worked on this before. Your help is needed. Thanks.
> 
> Leighton
> 
> 
> 
> 
> 
> 
> 
> 
>  
> Yahoo! Groups Links
> 
> 
> 
>  
> 
> 


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