AnsweredAssumed Answered

Using Internal crystal oscillator in lpc845

Question asked by angiey y on Oct 15, 2019
Latest reply on Nov 6, 2019 by Sabina Bruce



I'm using LPCXpresso845MAX [OM13097]development board, and developed the application to the

requirement needed in the development board, so same we designed a prototype board for further process,

the issue is the frequencies generated in different prototype board, i..e., whatever the PWM frequency

generated in the development board same is loaded to the prototype boards so there is difference

of frequencies with 0.01hz in some board,0.02 in some board.


When I test the 14.40hz[CONSTANT FREQUENCY] in dev board I get 14.40hz ,
but below are the frequencies getting when programmed the same code in
prototype board..
PROTO 1: 14.40 [MODE]----> 14.40HZ
PROTO 2 :14.40[MODE]------> 14.42HZ
PROTO 3 :14.40[MODE]------> 14.39HZ//and sometimes 14.41
PROTO 4 :14.40[MODE]------> 14.40HZ
Not using external crystal oscillator in the prototype board, but internal code setting is of the XTAL is 12Mhz,
is there anything to be change or called for the internal crystal oscillator in the code, since in the code called the
below function BOARD_BootClockFRO30M();[function which is used for PLL].
So is there any other internal function or library to be added for the internal crystal oscillator?
Thank you