// PIC Project Board

// PIC18F2550 + LTC2400 + LCD + USB

// Sample code demonstrates the use of sigma-delta converter.

// The program prints analog input 0-2.5V on LCD in micro Volts unit

// source code was compiled with Mikro-C compiler         



#define ADC_CS1 PORTC.F0 //            output bit

#define ADC_SDO PORTC.F1 // input bit

#define ADC_SCK PORTC.F2 // output bit





char *text = "PICProject Board";



unsigned long x1,x2,x3,x4,x5;



/* read 32-bit data from LTC2400            */



unsigned long read_ADC1(void)

           {

           char k;

           long n;

           n= 0;

           ADC_CS1 = 0;

           for(k=0; k<32; k++)

           {

           n<<= 1;

           ADC_SCK = 1;

           n |= ADC_SDO;

           ADC_SCK = 0;

           }

           ADC_CS1 = 1;

           n&=0x01fffffff; // maskout sign bit

           n>>=4; // get 24-bit conversion result

           return n;

           }



/* 5-point moving average */

// return data that scaled with reference voltage in uV unit



unsigned long filter_ADC(void)

           {

           x5 = x4;

           x4 = x3;

           x3 = x2;

           x2 = x1;

           x1 = read_ADC1();

           return ((((x1+x2+x3+x4+x5)/5)*148)/100); // x 149 E-9 convert to 2.479V

           }





 void main() 

{



           char buffer[20];

           long d;



           ADCON1 = 0x0E;

           TRISB = 0; // PORTB is output

           PORTC = 0xFF;

           TRISC = 0x02; // PORTC.1 is input bit

           Lcd_Init(&PORTB); // Initialize LCD connected to PORTB

           Lcd_Cmd(Lcd_CLEAR); // Clear display

           Lcd_Cmd(Lcd_CURSOR_OFF); // Turn cursor off

           Lcd_Out(1, 1, text);



          while(1)

           {

           PORTC.F7 ^= 1;

           d = filter_ADC();

           sprintl(buffer,"%08ld x0.1%cV",d,0xe4);

           Lcd_Cmd(LCD_SECOND_ROW);

           Lcd_Out_CP(buffer);

           Delay_ms(200);



            }

}