/*
 * File:   main.c
 * Author: sfokin
 *
 * Created on March 7, 2025, 4:38 PM
 */
#include <xc.h>
#define _XTAL_FREQ 8000000

// Configuration bits
#pragma config FOSC = INTOSCIO  // Internal oscillator
#pragma config WDTE = OFF       // Watchdog disabled
#pragma config PWRTE = OFF      // Power-up Timer disabled
#pragma config MCLRE = OFF      // MCLR pin as digital input
#pragma config CP = OFF         // Code protection off
#pragma config CPD = OFF        // Data code protection off
#pragma config BOREN = OFF      // Brown-out Reset disabled
#pragma config IESO = OFF       // Internal/External Switchover disabled
#pragma config FCMEN = OFF      // Fail-Safe Clock Monitor disabled

void __interrupt() isr(void) {
    INTCONbits.GIE = 0;
    
    if (PIR1bits.ADIF) {
        // Read ADC result
        unsigned int adc_result = 0;
        adc_result = ((ADRESH & 0x03) << 8) | ADRESL;
        
        // Update PWM duty cycle
        CCPR1L = adc_result >> 2;        // Upper 8 bits
        CCP1CONbits.DC1B = adc_result & 0x03; // Lower 2 bits
        
        // Clear interrupt flag and restart conversion
        PIR1bits.ADIF = 0;
        ADCON0bits.GO = 1;
    }
    
    INTCONbits.GIE = 1;
}

void main(void) {
    // Clock setup
    OSCCON = 0x70;             // 8MHz internal oscillator
    
    // GPIO configuration
    TRISIO = 0b00000010;       // GP1 input, GP2 output
    ANSEL = 0b00000010;        // AN1 analog, ADCS2=0 (Fosc/32)
    
    // ADC configuration
    ADCON0 = 0x85;             // ADON=1, CHS=AN1, ADCS=10 (Fosc/32)
    
    // PWM configuration
    PR2 = 0xFF;                // PWM period ~7.8kHz (1:1 prescaler)
    CCP1CON = 0x0C;            // PWM mode
    T2CON = 0x06;              // Timer2 on, prescaler 1:1
          
    // Interrupt configuration
    //PIR1bits.ADIF = 0;         // Clear ADC ready flag
    PIE1bits.ADIE = 1;         // Enable ADC interrupts
    INTCONbits.PEIE = 1;       // Enable peripheral interrupts
    INTCONbits.GIE = 1;        // Enable global interrupts
   
    // Start first conversion
    ADCON0bits.GO = 1;
    
    while(1) {
        // Main loop sleeps between conversions
        //SLEEP();
    }
}