2004810152947.c

c8051f120实现锁相环程序供你参考

//------------------------------------------------------------------------------------
// Blinky.c
//------------------------------------------------------------------------------------
// Copyright 2002 Cygnal Integrated Products, Inc.
//
// AUTH: BD
// DATE: 1 JUL 2002
//
// This program flashes the green LED on the C8051F120 target board about five times
// a second using the interrupt handler for Timer3.
// Target: C8051F12x
//
// Tool chain: KEIL Eval 'c'
//////////////////////////////////////////////////////
//在P0.0口测系统时钟频率
////////////////////////////////////////////////////////
//------------------------------------------------------------------------------------
// Includes
//------------------------------------------------------------------------------------
#include <c8051f120.h>                    // SFR declarations
   char i;

//-----------------------------------------------------------------------------
// 16-bit SFR Definitions for 'F12x
//-----------------------------------------------------------------------------

sfr16 RCAP3    = 0xCA;                 // Timer3 reload value
sfr16 TMR3     = 0xCC;                 // Timer3 counter

//------------------------------------------------------------------------------------
// Global CONSTANTS
//------------------------------------------------------------------------------------
unsigned int dey;
#define SYSCLK 3062500                    // approximate SYSCLK frequency in Hz

sbit  LED = P1^6;                         // green LED: '1' = ON; '0' = OFF

//------------------------------------------------------------------------------------
//
 //unsigned int dey;
// Function PROTOTYPES
//------------------------------------------------------------------------------------
void PORT_Init (void);
void Timer3_Init (int counts);
void Timer3_ISR (void);
//------------------------------------------------------------------------------------
// MAIN Routine
//------------------------------------------------------------------------------------
void main (void)

 {
   // disable watchdog timer
   WDTCN = 0xde;
   WDTCN = 0xad;

   SFRPAGE = CONFIG_PAGE;                 // Switch to configuration page
   PORT_Init ();

   SFRPAGE = TMR3_PAGE;                   // Switch to Timer 3 page
   Timer3_Init (SYSCLK / 12 / 10);        // Init Timer3 to generate interrupts
                                          // at a 10 Hz rate.
   EA = 1;											// enable global interrupts

   SFRPAGE = LEGACY_PAGE;                 // Page to sit in for now

   while (1)
 {             // spin forever
  while(dey==100)   
  {
     LED=!LED;    
	 dey=0;
  }
  }
 }
//------------------------------------------------------------------------------------
// PORT_Init
//------------------------------------------------------------------------------------
//
// Configure the Crossbar and GPIO ports
//
void PORT_Init (void)    

{
                             // software timer
     int i;  
   char SFRPAGE_SAVE = SFRPAGE;        // Save Current SFR page

   SFRPAGE = CONFIG_PAGE;              // set SFR page

   OSCXCN |= 0x67;
   OSCICN |= 0xc0;
   OSCICL |= 0x00;
for(i=0;i++;i<=256)   
 {}
for(i=0;i++;i<=256)   //延时1ms    
 {} 
while(OSCXCN==0x67)
     {   }

   //OSCICN = 0x83;                      // set internal oscillator to run
                                       // at its maximum frequency

   CLKSEL = 0x00;                      // Select the internal osc. as
   XBR1  |= 0x80;
   XBR2   |= 0x40;                     // Enable crossbar and weak pull-ups
   P0MDOUT |=0xff;
   
  P1MDOUT |= 0xff;                                     // the SYSCLK source

   //Turn on the PLL and increase the system clock by a factor of M/N = 2
  // SFRPAGE = CONFIG_PAGE;

 //  PLL0CN  = 0x00;                     // Set internal osc. as PLL source
   SFRPAGE = LEGACY_PAGE;
   FLSCL   = 0x10;                     // Set FLASH read time for 50MHz clk
                                       // or less
   SFRPAGE = CONFIG_PAGE;
   PLL0CN |= 0x01;                     // Enable Power to PLL
   PLL0DIV = 0x01;                     // Set Pre-divide value to N (N = 1)
   PLL0FLT = 0x01;                     // Set the PLL filter register for
                                       // a reference clock from 19 - 30 MHz
                                       // and an output clock from 45 - 80 MHz
   PLL0MUL = 0x05;                     // Multiply SYSCLK by M (M = 2)

   for (i=0; i < 256; i++) ;           // Wait at least 5us
   PLL0CN  |= 0x07;                    // Enable the PLL
   while(!(PLL0CN & 0x10));            // Wait until PLL frequency is locked
   CLKSEL  = 0x02;                     // Select PLL as SYSCLK source

   SFRPAGE = SFRPAGE_SAVE;             // Restore SFR page
}
//------------------------------------------------------------------------------------
// Timer3_Init
//------------------------------------------------------------------------------------
//
// Configure Timer3 to auto-reload and generate an interrupt at interval
// specified by <counts> using SYSCLK/12 as its time base.
//
//
void Timer3_Init (int counts)
{
   TMR3CN = 0x00;                      // Stop Timer3; Clear TF3;
                                       // use SYSCLK/12 as timebase
   RCAP3   = -counts;                  // Init reload values
   TMR3    = 0xffff;                   // set to reload immediately
   EIE2   |= 0x01;                     // enable Timer3 interrupts
   TR3 = 1;                            // start Timer3
}

//------------------------------------------------------------------------------------
// Interrupt Service Routines
//------------------------------------------------------------------------------------

//------------------------------------------------------------------------------------
// Timer3_ISR
//------------------------------------------------------------------------------------
// This routine changes the state of the LED whenever Timer3 overflows.
//
// NOTE: The SFRPAGE register will automatically be switched to the Timer 3 Page
// When an interrupt occurs.  SFRPAGE will return to its previous setting on exit
// from this routine.
//
void Timer3_ISR (void) interrupt 14
     
 {
    TF3 = 0;                               // clear TF3      
     dey++;
     LED=!LED;
   }