ARM Technical Support Knowledge Articles

USING THE RC OSCILLATOR FOR PHILIPS LPC CH

Applies to: uVision Debugger

Answer


Information in this article applies to:


QUESTION

How do I configure my project so that my application uses the Internal RC Clock of the Philips LPC devices?

ANSWER

There is a startup file named STARTLPC.A51 in the KEILC51LIB folder. This file contains all the configuration options for the LPC devices. Copy it to your project directory and include it in your project.

To change the options for the Oscillator Frequency, scan through this file for the following section and change the FOSC EQU to have the value 3.

;  Setup LPC Configuration Register (UCFG1, UCFG2)
;
; Oscillator Configuration (UCFG1.0 .. UCFG1.2)
; FOSC       Val  Description
; ----       ---  -----------
FOSC EQU 7  ; 0 = high frequency crystal or resonator (4MHz .. 20MHz)
;           ; 1 = medium frequency crystal or resonator (100kHz .. 4MHz)
;           ; 2 = low frequency crystal (20kHz .. 100kHz)
;           ; 3 = internal RC oscillator (6MHz +/- 25%)
;           ; 7 = (default on unprogrammed part) external clock input on X1

Article last edited on: 2005-08-04 07:30:20

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