pwm

#include <xc.h>                                     //PIC hardware mapping
#include<pic16f1829.h>
#define _XTAL_FREQ 500000                            //Used by the XC8 delay_ms(x) macro
//totale stap cycle van 256 stappen duurt 8 seconde elke stap duurt dus 32 miliseconde elke instrucite duurt  0,008 mili seconde 32/0,008 = 4000 stappen nodig maar de timer heeft maar 255 stappen dus gebruik maken van post of pre scalar.dus een scalar van 1:16.
#define vertraging32 60500 //= 32000 (milisec) / 16 (want prescalar = 1:2 en 65536 (2^16) - 2000 = 63536)

//config bits that are part-specific for the PIC16F1829
#pragma config FOSC=INTOSC, WDTE=OFF, PWRTE=OFF, MCLRE=OFF, CP=OFF, CPD=OFF, BOREN=ON, CLKOUTEN=OFF, IESO=ON, FCMEN=ON
#pragma config WRT=OFF, PLLEN=OFF, STVREN=OFF,BORV = LO, LVP=OFF


typedef enum {
    dim,
    fel,
    noppes
} knop;

unsigned int index = 0;
volatile knop vroeger = dim;
volatile knop nu = noppes;

void init(void) {
    //setup clock
    OSCCON = 0b00111000; //500KHz clock speed
    //set up leds
    TRISC = 0; //all LED pins are outputs
    LATC = 0;
    //set up button
    TRISAbits.TRISA2 = 1; //switch as input
    ANSELAbits.ANSA2 = 0; //digital switch

    //setup the PWM
    CCP2CON = 0b00001100; //PWM mode single output
    PR2 = 255; //Frequency at 486Hz. Anything over ~60Hz will get rid of any flicker
    //PWM Period = [PR2 + 1]*4*Tosc*T2CKPS = [255 + 1] * 4 * (1 / 500KHz) * 1
    CCPTMRSbits.C2TSEL = 0b00; //select timer2 as PWM source
    T2CONbits.T2CKPS = 0b00; //1:1 prescaler
    T2CONbits.TMR2ON = 1; //start the PWM

    //setup TIMER1 as the delay
    T1CON = 0x10; // Fosc/4, prescaler 1:2, tmr1 of
    //1:256 prescaler for a delay of: (insruction-cycle * 256-counts)*prescaler = ((8uS * 256)*256) =~ 524mS

    TMR1IE = 1;
    PIE1bits.TMR1IE = 1; //enable the TMR4 rollover interrupt
    PIR1bits.TMR1IF = 0;
    //setup interrupt on change for the switch
    INTCONbits.IOCIE = 1; //enable interrupt on change global
    IOCANbits.IOCAN2 = 1; //when SW1 is pressed, enter the ISR

    PEIE = 1;
    GIE = 1; //enable global interupt
}

void __interrupt() ISR() {
    if (PORTAbits.RA2 == 0 && IOCAFbits.IOCAF2 == 1) {
        IOCAFbits.IOCAF2 = 0; //flag = clear
        if (vroeger == dim) {
            vroeger = fel;
            nu = fel;
        } else {
            vroeger = dim;
            nu = dim;
        }
    } else if (PORTAbits.RA2 == 1 && IOCAFbits.IOCAF2 == 1) {
        IOCAFbits.IOCAF2 = 0;
        nu = noppes;
    }

    if (PIR1bits.TMR1IF == 1) {
        PIR1bits.TMR1IF = 0;
        TMR1 += vertraging32;

        switch (nu) {
            case noppes:
                break;

            case dim:
                if (index > 0) {
                    index--;
                }
                break;

            case fel:
                if (index < 255) {
                    index++;
                }
                break;
        }
    }

    CCPR2L = ((PWM_Lookup[index] >> 2) & 0xFF);
    CCP2CONbits.DC2B = ((PWM_Lookup[index] >> 8) & 0x03);
}

void main() {
    init();

    while (1) {

    }


}