help regarding PLL in LPC2378?

[nagarajanj21]

my question about we use external oscillator of about 12MHz frequency and will give input to PLL we get 60-72 MHz in LPc2378. what happened when we use external oscillator as 60 mhz instead of using PLL. help me...


thanks in advance...

 

[alexan_e]

According to the datasheet
page 32 ,
"The main oscillator can be used as the clock source for the CPU, with or without using the
PLL. The main oscillator operates at frequencies of 1 MHz to 25 MHz. This frequency can
be boosted to a higher frequency, up to the maximum CPU operating frequency, by the PLL"

So i don't think that you can use an external clock of 60MHz, and why would you when you have the PLL to multiply any frequency internally.

Alex