Content originally posted in LPCWare by Dilberto on Sat Mar 01 07:32:39 MST 2014
Quote:
What is the max frequency of LPC-812 Board?
What is the max frequency of pll ?
According to NxP doc UM10601 ( LPC800 User manual, Rev. 1.3 — 22 July 2013 ) :
Quote:
The input frequency range is 10 MHz to 25 MHz.
The CCO frequency range is 156 MHz to 320 MHz.
Remark: The divider values for P and M must be selected so that the PLL output clock
frequency FCLKOUT is lower than 100 MHz because the main clock is limited to a
maximum frequency of 100 MHz
Kindly remember that, in the LPC812-Max Board, the crystal, although present in the board, is NOT wired to the microcontroller.
This can be done by changing jumpers SJ2 and SJ3 ( see attached figure ).
The processor can run with CPU clock up to 30 MHz without introducing wait states ( see Flash Memory Controller ( FMC ) register set, pg 260 of referred manual ).
Above this value and up to 100 MHz, wait states must be introduced for memory access.
However, beware of the power consumption! As higher the frequency used, higher the power consumption is.
Hope this helps.
