//PWM1
//Program to test PWM feature

//Written for PIC12F683 and CC5X compiler
//Personal and non-commercial use encouraged
//Copyright 2007 - David Theunissen - See www.flyelectric.ukgateway.net

//PREPROCESSOR section ========================================================

#include "12F683.H"				//PIC chip file

#pragma config = 0b.11.1100.0100//Core device configuration


//VARIABLES section ===========================================================

#define LED GPIO.0
	

//FUNCTIONS section ===========================================================
	
void main()
{
//Set port levels to known state
	GPIO = 0;
    
//Configure ports as Input (1) or Output (0)
	TRISIO.0 = 0;				//Sets GP0 to be Output for LED
	TRISIO.2 = 0;				//Sets GP2 (CCP1) to be Output for PWM

//Set ADC ports    							
    ANSEL.0 = 0;				//Set ADC port AN0 to Digital
    ANSEL.2 = 0;				//Set ADC port AN2 to Digital
       
//Set comparitor
    CMCON0 = 0b.111;			//Switches all 3 comparator ports off

//Set clock frequency (011 = 500khz)
	OSCCON.6 = 0;
	OSCCON.5 = 1;
	OSCCON.4 = 1;

//Set up Timer 2 (used by PWM)
	T2CON.2 = 1;				//Enables Timer2
    T2CON.1 = 1;				//Sets Timer2 prescaler to 16
    T2CON.0 = 0;				//Part of above
	
//Set PWM period / frequency
    PR2 = 156;					//20ms with 500khz clock
    
//Set PWM duty cycle ('on' time) - the 3 registers concatenate into one 10bit number
//32 = 0b100000 = ~1ms high with 500khz clock
    CCPR1L = 0b1000;			//High 8bits
    CCP1CON.5 = 0;				//2nd lowest bit
    CCP1CON.4 = 0;				//Lowest bit
    
//Enable PWM
    CCP1CON.3 = 1;				//CCP1 mode select - enables PWM mode
    CCP1CON.2 = 1;				//Part of above
    
    
    LED = 1;					//So you know circuit is powered up
    
    while(1);					//Keeps checking the while condition but does nothing else
    							//(PIC needs to keep 'busy' for PWM to keep running too)
    
}							//end main