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jason1987

Mon Jun 29 2009, 07:57PM

Registered Member #19032

Joined: Wed Jun 03 2009, 08:28PM

Posts: 27
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what does the following code do?

CODE:

#include<c8051f200.h> //

//definitions

sbit LED = P2^4;

void adc_init(); //to initialize adc

void port_init(); //to initialize the ports

void main()

{

unsigned int index=0, total_period= (unsigned int) 255*256, on_time=0;

port_init();

adc_init();

   // disable watchdog timer

   WDTCN = 0xde;

   WDTCN = 0xad;

    {

        ADBUSY = 0x01;                          //starts the adc conversion

        while(ADCINT);                            //polling for ADCINT which tells us the end of conversion

        ADCINT = 0x00;

        on_time = ((unsigned int)ADC0H)*256;

        for ( index = 0 ; index < total_period ; index++)

        {

            if (on_time--)

            {

                LED = 0x01; //switching on the LED

            }

            else

            {

                LED = 0x00; //switching off the LED

            }

        }

    }  

}

void adc_init ()

{

    AMX0SL = 0x3f;                         // enable AMUX & configure for p3.7 as i/p pin

    ADC0CF = 0x60;                         // set conversion clk at one sys clk and PGA at gain =1

    ADC0CN = 0xC0;                         // ADC is enabled and ADBUSY=0 (changed here)

    REF0CN = 0x03;                         // VDD is selected as Vref. Here are you using VDD for variable resistor also?

}

void port_init()

{

    P3MODE = 0X7F;                   // Except the P3.7 pin all are configured as digital I/O

}