ad.c

silicon lab 单片机 C8051F320的ADC控制程序

// Release 1.0
//    -Initial Revision (clm)
//    2008-11-13
//-----------------------------------------------------------------------------
// Includes
//-----------------------------------------------------------------------------

#include "c8051F320.h"                 // SFR declarations
#include <stdio.h>

//-----------------------------------------------------------------------------
// 16-bit SFR Definitions for 'F34x
//-----------------------------------------------------------------------------
sfr16 ADC0     = 0xbd;                 // ADC0 result

//-----------------------------------------------------------------------------
// Global CONSTANTS
//-----------------------------------------------------------------------------

#define SYSCLK       12000000          // SYSCLK frequency in Hz

sbit LED = P2^2;                       // LED='1' means ON

idata float volt;
//-----------------------------------------------------------------------------
// Function PROTOTYPES
//-----------------------------------------------------------------------------

void SYSCLK_Init (void);
void PORT_Init (void);
void ADC0_Init(void);
void ADC0_Conver(void);
//-----------------------------------------------------------------------------
// MAIN Routine
//-----------------------------------------------------------------------------

void main (void) 
{
   PCA0MD &= ~0x40;                    // WDTE = 0 (clear watchdog timer 
                                       // enable)

   SYSCLK_Init ();                     // Initialize system clock to 
                                       // 12MHz
   PORT_Init ();                       // Initialize crossbar and GPIO
   //Timer2_Init();                      // Init Timer2 to generate 
                                       // overflows to trigger ADC
   //UART0_Init();                       // Initialize UART0 for printf's
   ADC0_Init();                        // Initialize ADC0

   //EA = 1;							         // enable global interrupts
   while (1)
   {      
    	ADC0_Conver();                  
   }
}

//-----------------------------------------------------------------------------
// Initialization Subroutines
//-----------------------------------------------------------------------------
//
//-----------------------------------------------------------------------------
// SYSCLK_Init
//-----------------------------------------------------------------------------
// 
// Return Value:  None
// Parameters:    None
//
// This routine initializes the system clock to use the internal 12MHz 
// oscillator as its clock source.  Also enables missing clock detector reset.
//
//-----------------------------------------------------------------------------
void SYSCLK_Init (void)
{
   OSCICN = 0x83;                      // configure internal oscillator for
                                       // 12MHz / 1
   RSTSRC = 0x04;                      // enable missing clock detector
}

//-----------------------------------------------------------------------------
// PORT_Init
//-----------------------------------------------------------------------------
//
// Return Value:  None
// Parameters:    None
//
// Configure the Crossbar and GPIO ports.
// P0.4 - UART TX (push-pull)
// P0.5 - UART RX 
// P2.4 - ADC0 analog input
// P2.2 - LED (push-pull)
// 
//-----------------------------------------------------------------------------

void PORT_Init (void)
{
   //XBR0     = 0x01;                    // Enable UART0
   XBR1     = 0x40;                    // Enable crossbar and weak pull-ups
   P0MDOUT |= 0x10;                    // Set TX pin to push-pull
   P2MDOUT |= 0x04;                    // enable LED as a push-pull output
   //P2MDIN &= ~0x10;                    // set P2.4 as an analog input

   P1MDIN &= ~(1<<0);
   P1SKIP |=  (1<<0);
}

//-----------------------------------------------------------------------------
// ADC0_Init
//-----------------------------------------------------------------------------
//
// Return Value:  None
// Parameters:    None
//
// Configures ADC0 to make single-ended analog measurements on pin P2.4
//  
//-----------------------------------------------------------------------------

void ADC0_Init (void)
{

   AD0EN = 0;                      // ADC0 disabled, normal tracking, 
                                       // conversion triggered on TMR2 overflow

   REF0CN = 0x03;                      // Enable on-chip VREF and buffer

   AMX0P |= 0x0;                       // ADC0 positive input = P1.0
   AMX0N |= 0x1F;                       // ADC0 negative input = GND
                                       // i.e., single ended mode

   ADC0CF = ((SYSCLK/3000000)-1)<<3;   // set SAR clock to 3MHz

   ADC0CF |= 0x00;                     // right-justify results   
}

void ADC0_Conver(void)
{
	unsigned int temp;
	AD0EN = 1;                          // enable ADC0
	AD0BUSY=1;
	while(!AD0INT);
	AD0INT=0;
	temp=ADC0;
	volt=temp*0.00234375;
}

//-----------------------------------------------------------------------------
// End Of File
//-----------------------------------------------------------------------------