// PIC18F14K50 in C - Versione 0.7 - Febbraio 2012
// Copyright (c) 2010-2012 VincenzoV.net
// Creative Commons | Attribuzione-Condividi allo stesso modo 3.0 Unported.
// Creative Commons | Attribution-Share Alike 3.0 Unported
// https://www.vincenzov.net/tutorial/elettronica-di-base/PIC18F14K50

// Using internal ADC - Version 2

#include <p18f14k50.h>

#pragma config FOSC = IRCCLKOUT  // Internal RC oscillator (F/4 to OSC2 - pin 3) 
#pragma config WDTEN = OFF       // Watchdog disabled
#pragma config LVP = OFF         // Disable Low Voltage Programming
#pragma config MCLRE = ON        // Master clear enabled

void main(void)
{ unsigned int voltage;
  
  OSCCON=0x70;          // Select 16 MHz internal clock

  TRISC = 0x00;	        // Set PORTC as Output
  ANSEL = 0;            // Set as Digital I/O
  ANSELH = 0;           // Set as Digital I/O

  TRISBbits.TRISB4 = 1; // Set RB4  (pin 13, aka AN10) to input
  ANSELHbits.ANS10 = 1; // Set AN10 (pin 13, aka RB4) to analog
  
  ADCON0=0b00101001;   // Channel AN10 (xx10 10xx), Enable ADC (xxxx xxx1)
  ADCON1=0b00000000;   // VDD and VSS as voltage reference (xxxx 0000)
  ADCON2=0b00001101;   // Left justify result (0xxx xxx), 2 TAD delay (xx00 1xxx), TAD = 1 us (Fck/16 = 1 Mhz) (xxxx x101) 
  
  for (;;) 
  { ADCON0bits.GO = 1;         // Start conversion
    //PORTCbits.RC4 = 1;       // RC4 up at start of conversion - Debug and timing
    while (ADCON0bits.GO);     // Wait conversion done
    //PORTCbits.RC4 = 0;       // RC4 down at end of conversion - Debug and timing
    
    voltage = ADRESH;                // Read ADC high register and convert to 0-255 integer  
     
    PORTC = (voltage >> 4) & 0x0F;   // Dispaly 4 MSB
  }
}