/*
   ADC.C sample program interfaces LTC1298/MCP3202 12-bit
   Analog-to-Digital Converter

   The converted digital data was displayed with onboard LCD

   22 Nov 2004
   Written by W.SIRICHOTE, kswichit@kmitl.ac.th

*/

#include <8051io.h>  /* include i/o header file */
#include <8051reg.h>
#include <8051bit.h>

#define Data P1.1
#define CLK P1.2
#define CS P1.3


#include "lcddrv.c"

char buffer[20];

int read_ADC(char n)
{
	int k;
	char i,channel;
	k=0;

        clrbit(CS)

	if(n==0) channel= 0x0d;
	else channel= 0x0f;

// send config nibble dummy read NULL bit after config nibble
     for(i=0; i<4; i++)
	{

                 clrbit(CLK)
                 if(channel&8) setbit(Data)
                 else clrbit(Data)
                 setbit(CLK)
		 channel <<=1;
	}

        P1 |= 2; // change to input bit
        clrbit(CLK)  

// now read 12-bit data
    for(i=0; i<12; i++)
	{
	        k<<=1;
                setbit(CLK)
                clrbit(CLK)
                if(P1&2) k |=1;
                 else k &= ~1;
	}
            setbit(CS)

        return k&=0xfff;
}


void main(void)
{
    InitLcd();

     while(1)
     {
     P1 ^=0x80;  // blink onboard LED
     sprintf(buffer,"ADC0=%d   ",read_ADC(0));
   //  printf("\n%s",buffer);
     goto_xy(0,0);
     Puts(buffer);

     sprintf(buffer,"ADC1=%d   ",read_ADC(1));
   //  printf(" %s",buffer);
     goto_xy(0,1);
     Puts(buffer);

   //  delay(100);
     }
}