I followed this Tutorial and changed the code for my Micro-controller 16f1827. I also changed the function of the code. It should turn on a LED if the ADC Value is more than half of max. ADC Value and turn off a LED if less than half.
// CONFIG
#pragma config FOSC = HS // Oscillator Selection bits (HS oscillator)
#pragma config WDTE = OFF // Watchdog Timer Enable bit (WDT disabled)
#pragma config PWRTE = OFF // Power-up Timer Enable bit (PWRT disabled)
#pragma config BOREN = OFF // Brown-out Reset Enable bit (BOR disabled)
#pragma config LVP = OFF // Low-Voltage (Single-Supply) In-Circuit Serial Programming Enable bit (RB3 is digital I/O, HV on MCLR must be used for programming)
#pragma config CPD = OFF // Data EEPROM Memory Code Protection bit (Data EEPROM code protection off)
#pragma config WRT = OFF // Flash Program Memory Write Enable bits (Write protection off; all program memory may be written to by EECON control)
#pragma config CP = OFF // Flash Program Memory Code Protection bit (Code protection off)
#include <xc.h>
#include <pic16f1827.h>
#define _XTAL_FREQ 8000000
void ADC_Init()
{
ADCON0 = 0x81; //Turn ON ADC and Clock Selection
ADCON1 = 0x00; //All pins as Analog Input and setting Reference Voltages
}
unsigned int ADC_Read(unsigned char channel)
{
if(channel > 7) //Channel range is 0 ~ 7
return 0;
ADCON0 &= 0xC5; //Clearing channel selection bits
ADCON0 |= channel<<3; //Setting channel selection bits
__delay_ms(2); //Acquisition time to charge hold capacitor
GO_nDONE = 1; //Initializes A/D conversion
while(GO_nDONE); //Waiting for conversion to complete
return ((ADRESH<<8)+ADRESL); //Return result
}
void main()
{
unsigned int a;
TRISA = 0xFF; //Analog pins as Input
TRISB = 0x00; //Port B as Output
//TRISC = 0x00; //Port C as Output
ADC_Init(); //Initialize ADC
do
{
a = ADC_Read(0); //Read Analog Channel 0
//PORTB = a; //Write Lower bits to PORTB
//PORTC = a>>8; //Write Higher 2 bits to PORTC
if(a > 512){
PORTBbits.RB7 = 1;
}else{
PORTBbits.RB7 = 0;
}
__delay_ms(100); //Delay
}while(1); //Infinite Loop
}
The Code compiles without error in XC8. The problem is the PIC detects the ADC changes too slow. If I take the Input pin and connect it to the positive reference Value it turns on the LED with a Delay of maybe 2 Seconds. The same happens when I change the ADC Input to 0v. All changes are detected very slow. Why is the ADC working so slow?
