Lpc2000

"Crystal Oscillator" section in the "System Control Block" chapter of 
the LPC2114/2124/2212/2214 and LPC2119/2129/2194/2292/2294 User 
Manuals covers input frequency range topics.

If on-chip PLL system or boot-loader is used, input clock frequency 
is limited to exclusive range of 10 MHz to 25 Mhz. 

These restrictions are imposed by the design of the PLL circuitary. 
Since all Philips LPC2000 parts have the same PLL module, above 
requirements exist in the case of LPC2104/5/6 parts, too.

Regards,

Philips Apps Team



--- In lpc2000@yahoogroups.com, "tphatrapornnant" <tp35@l...> wrote:
> Hi,
> 
> As I remember, I used to try 2.0 MHz crystal oscilator but it 
seemed 
> PLL can't work at lower than 10MHz. I have just tested by changing 
> OSC from now 10 MHz to 2 MHz with 6 time multiplier. The 1 ms 
> interrupt timer changed to 1.8 ms, it should be 5 ms. So, I afraid 
it 
> doesn't work at 4 MHz.    
> 
> Teera.
> 
> --- In lpc2000@yahoogroups.com, "microbit" <microbit@c...> wrote:
> > Hi All,
> > 
> > This might have come up before I think, but I can't seem to
> > readily find it in my LPC2000 folder.
> > 
> > Has anyone ever tried supplying LPC2000 with an external 4 MHz
> > clock signal, to be used with PLL at higher clock rates ?
> > 
> > Since it's a full swing Ext signal, I don't see any limitations, 
> other
> > than the osc buffer ckty, which surely should handle that.
> > I'm thinking of multiplying up to 64 MHz cclk.. a tad too high.
> > And 8 X = 32 MHz is too low.
> > This is for LPC2119/29.
> > Space is critical and I need to save an SMT Xtal real estate wise.
> > 
> > -- Kris