adc_8bits.c

透過C51的程式

/**
 * @file $RCSfile: Adc_8bits.c,v $
 *
 * Copyright (c) 2004 Atmel.
 *
 * Please read file license.txt for copyright notice.
 *
 * @brief This file is an example to use Adc.
 *
 * This file can be parsed by Doxygen for automatic documentation
 * generation.
 * Put here the functional description of this file within the software
 * architecture of your program.
 *
 * @version $Revision: 1.0 $ $Name:  $
 */

/* @section  I N C L U D E S */
#include "t89c51cc01.h"

unsigned char value_converted=0x00; /* converted value */
unsigned char value_AN6=0x00;       /* converted AN6 value */
unsigned char value_AN7=0x00;       /* converted AN7 value */
bit end_of_convertion=0;            /* software flag */

/**
 * FUNCTION_PURPOSE:this function setup Adc with channel 6 and 7 and start 
 * 8bits convertion.
 * FUNCTION_INPUTS:void
 * FUNCTION_OUTPUTS:void
 */
void main(void)
{
/* configure channel P1.6(AN6) and P1.7(AN7) for ADC */
ADCF = 0xC0;                        

/* init prescaler for adc clock */
/* Fadc = Fperiph/(2*(32-PRS)), PRS -> ADCLK[4:0] */
ADCLK = 0x06;                       /* Fosc = 16 MHz, Fadsc = 153.8khz */

ADCON = 0x20;                       /* Enable the ADC */


EA = 1;                             /* enable interrupts */
EADC = 1;                           /* enable ADC interrupt */
while(1)
{
   ADCON &= ~0x07;                  /* Clear the channel field ADCON[2:0] */
   ADCON |= 0x06;                   /* Select channel 6 */
   ADCON &= ~0x40;                  /* standard mode */
   ADCON |= 0x08;                   /* Start conversion */

   while(!end_of_convertion);       /* wait end of convertion */
   end_of_convertion=0;             /* clear software flag */
   value_AN6=value_converted;       /* save converted value */


   ADCON &= ~0x07;                  /* Clear the channel field ADCON[2:0] */
   ADCON |= 0x07;                   /* Select channel 7 */
   ADCON &= ~0x40;                  /* standard mode */
   ADCON |= 0x08;                   /* Start conversion */

   while(!end_of_convertion);       /* wait end of convertion */
   end_of_convertion=0;             /* clear software flag */
   value_AN7=value_converted;       /* save converted value */

}
}


/**
 * FUNCTION_PURPOSE:Adc interrupt, save ADDH into an unsigned char
 * FUNCTION_INPUTS:void
 * FUNCTION_OUTPUTS:void
 */
void it_Adc(void) interrupt 8
{
ADCON &= ~0x10;                     /* Clear the End of conversion flag */
value_converted = ADDH;             /* save value */
end_of_convertion=1;                /* set flag */
}