adcmain.c

P87C591的a/d 转换程序

/*------------------------------------------------------------------------------
adcMain.c : Sample Program that demonstrates the A to D converter of the 
following microcontrollers

Philips 80C591
Philips 83C591
Philips 87C591
Philips 80C552
Philips 83/87C552
Philips 87C552
Philips 80C554
Philips 83/87C554
Philips 83/87C557E4
Philips 83/87C557E8


Copyright (c) 1988-2001 Keil Elektronik GmbH and Keil Software, Inc.
All rights reserved.
--------------------------------------------------------------------------*/

#include <REG591.h>
#include <stdio.h>

#define V_REF 5

/*------------------------------------------------------------------------------
Read_ADC( unsigned char ): reads an analog signal from the received unsigned
char and returns the converted value
------------------------------------------------------------------------------*/
unsigned Read_ADC( unsigned char channel )
{
  ADCON &= ~0x07;            /* Clears the input channels */
  ADCON |= 0x07 & channel;   /* Loads Channel to sampled */

  ADCON |= 0x8;              /* Starts Conversion */
  while(  (ADCON & 0x8) );   /* Waits for Conversion to end */
  return( ( ( (unsigned) ADCH << 8) | ADCON ) >> 6 );		
}

unsigned int reading[8];
/*------------------------------------------------------------------------------
main() : Outputs the digital conversion of channels 0 - 7.
------------------------------------------------------------------------------*/
void main( void )
{
  unsigned int i;

	/*------------------------------------------------
	Setup the serial port for 1200 baud at 16MHz.
	------------------------------------------------*/
  S0CON  = 0x50;		           /* SCON: mode 1, 8-bit UART, enable rcvr      */
  TMOD  |= 0x20;               /* TMOD: timer 1, mode 2, 8-bit reload        */
  TH1    = 221;                /* TH1:  reload value for 1200 baud @ 16MHz   */
  TR1    = 1;                  /* TR1:  timer 1 run                          */
  TI     = 1;                  /* TI:   set TI to send first char of UART    */
	

  ADCON = 0x20; 				/* Set Startmode to start via software */
  while(1)
  {
    for( i = 0; i < 2 ; i++ )
    {
      i = 0;
      reading[i] = Read_ADC(i);
      //printf ("ADC #%u Count %4u = %01u.%04u Volts\r",
      //  (unsigned) i, (unsigned) reading[i],
      //  (unsigned) (reading[i] * V_REF) >> 10,                        /* Output Integer Portion */
      //  (unsigned) ((reading[i] * V_REF * 10000UL) >> 10UL) % 10000); /* Output Decimal Portion */      
      ADCON &= ~0x10;		/*Resets to Ready to Read Flag.   */
    }
  }
}