#include "adc.h"

/* ADCON0: bit 7 - bit 0 (11-1 pg 111)
 *         ADCS1:ADCS0:CHS2:CHS1:CHS0:GO/DONE:-:ADON
 * 
 * ADCON1: bit 7 - bit 0
 *         ADFM:-:-:-:PCFG3:PCFG2:PCFG1:PCFG0
 */

void Adc_Init(void) {
    ADCON0 = 0x00; // A/D Off, GO_DONE not in progress, Channel 0, Fosc/2
    ADCS0 = 0; // A/D Conversion Fosc/32 ADCS1:ADCS0 (0b10) (Table 11-1)
    ADCS1 = 1;

    //ADCON1
    ADFM = 1; // results right justified
    
    //16F887
    //VCFG0 = VCFG1 = 0; // AN0-AN7 Analog input, Vref+/- Vdd/Vss
    
    //16F877A
    PCFG0 = PCFG1 = PCFG2 = 0;
}

unsigned int Adc_Read(unsigned int channel) {
    ADCON0bits.CHS = channel; // Set CHS bits for channel (pg111)
    ADCON0bits.ADON = 1; // Turn on ADC
    __delay_us(5); // Enough time for A/D acquisition
    ADCON0bits.GO_DONE = 1; // A/D Conversion bit set 1 (conversion in progress)
    while (ADCON0bits.GO_DONE == 1); // Wait for conversion to finish
    return ((ADRESH << 8) + ADRESL); // return combined 10 bits of conversion
}