/*
 * ADC.C
 * read 40-bit data from PIC16C715 4-channel 8-bit resolution ADC
 * and 7-bit input port_B
 *  P3.5 SCLK
 *  P3.4 SDA
 * c:\mc\cc51 %1 -ilp h=c:\mc m=s s=c52robot.asm  < need new startup file
 * 
 * Copyright (c) 2000 by Wichit Sirichote
 */

#include "c:\mc\8051io.h"  /* include i/o header file */
#include "c:\mc\8051reg.h"
#include "c:\mc\8051bit.h"

extern register char cputick;

unsigned register char i,j,temp,x;
unsigned register char buffer[5];

#define SCLK P3.5
#define SDA P3.4

#define LED P1.3   // for testing

main()
{
   while(1)
   {
      disable();
    // read_40bit();    // swap two versions which one is faster
      read_ADC();
      see_sensor();
 //     printf("\n%u %u %u %u %08b",buffer[0],buffer[1],buffer[2],buffer[3],buffer[4]);
   }
}

pause(int j)
{
   int i;
   for (i = 0; i < j; i++)
   ;
}

read_40bit(){  // read ADC and input port from 715 converter
        disable();
        setbit(LED)
        clrbit(SCLK)       // start bit
        pause(10);
        for(j=0;j<5;j++)   /* outer loop 5-byte */
        {
        for(i=0;i<8;i++)    /* inner loop 8-bit */
        {
         clrbit(SCLK)
         pause(3);
         setbit(SCLK)        /* produce rising edge pulse */
         pause(3);
         asm {
            setb SDA
            mov A,temp
            mov C,SDA      // read data put to carry flag
            rrc A           /* shift carry flag into A, save to temp */
            mov temp,A
             }
        }
        buffer[j] = temp; /* save temp to BUFFER[j] */
        }
        clrbit(LED)
      //  enable();
}

read_ADC()  //use rrc instruction shifting SDA in 40-bit register
{
        disable();
        setbit(LED)
        clrbit(SCLK)       // start bit
        pause(10);
        for(i=0;i<40;i++)    /* loop 40-bit */
        {
         clrbit(SCLK)
         pause(3);
         setbit(SCLK)        /* produce rising edge pulse */
         pause(3);
       asm{          // 40-bit SIPO register using buffer[5]
       setb  SDA
       mov   C,SDA
       mov   A,buffer+4
       rrc   A
       mov   buffer+4,A
       mov   A,buffer+3
       rrc   A
       mov   buffer+3,A
       mov   A,buffer+2
       rrc   A
       mov   buffer+2,A
       mov   A,buffer+1
       rrc   A
       mov   buffer+1,A
       mov   A,buffer
       rrc   A
       mov   buffer,A
       }
         }
       clrbit(LED)
      // enable();
}

see_sensor()
{
   //    putch(13);
       printf("%03u\n",buffer[0]);
    //  if(buffer[1]>=80)
       x= (buffer[0])/3;
       x+=10;
       for(i=0;i<x; i++)
       putch(' ');
       putch('x');
       putch(13);
}