rtcmainclock_abstract.txt

LPCXpresso1768

The RTCmainclock project is a simple program for the NXP 'LPC1768' 
microcontroller using Keil 'MCB1700' evaluation board, and 
demonstrates how to configure the RTC as main clock source.

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!!
!! This example demonstrates example 2 of chapter "Examples of PLL0 settings" 
!! in the LPC17xx User manual.
!! Please read this chapter and chapter "PLL0 setup sequence" carefully!
!!
!! Do not use the USB in this configuration!
!!
!! This example uses it own system_LPC17xx.c file: system_LPC17xx_RTCmain.c!
!!
!! NOTE ! NOTE ! NOTE ! NOTE ! NOTE ! NOTE ! NOTE ! NOTE ! NOTE ! NOTE ! NOTE ! NOTE ! NOTE ! NOTE ! NOTE !!
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In the "Configuration wizard" in system_LPC17xx_RTCmain.c several clock settings can be done. The 
PLL clock source is selected to be the RTC oscillator. PLL0 is configured to have a 288MHz output 
creating a 288/4 = 72 MHz CClk.


Example functionality:                                                   
 - Clock Settings:
   - RTC  =  32.768 kHz
   - PLL0_MSEL = 8789
   - PLL0_NSEL = 2
   - PLL0  = 288 MHz
   - CCLK  =  72 MHz