f52x_blinky.c

8051试验程序 基础教材

//-----------------------------------------------------------------------------
// F52x_Blinky.c
//-----------------------------------------------------------------------------
// Copyright 2006 Silicon Laboratories, Inc.
// http://www.silabs.com
//
// File Description:
//
// This file blinks the LED at a constant rate.
//
//
// How To Test:
//
// 1) Download code to either Side A or Side B of a C8051F530 target board
// 2) Ensure that the LED jumper is shorted; The jumper is located on
//    HDR3 for the Side A LED and HDR4 for the Side B LED.
// 3) Run the code and if the LED blinks, the code works
//
//
// FID:            52X000005
// Target:         C8051F52x/53x
// Command Line:   None
//
// Release 1.0
//    -Initial Revision (CG)
//    -07 SEP 2006
//
//-----------------------------------------------------------------------------
// Includes
//-----------------------------------------------------------------------------

#include <ioc8051f520.h>                 // SFR declarations

//-----------------------------------------------------------------------------
// 16-bit SFR  and SBIT definitions
//-----------------------------------------------------------------------------

__sfr __no_init volatile unsigned short TMR2R @ 0xCA;                   // Timer2 16-bit reload reg. definition
__sfr __no_init volatile unsigned short TMR2  @ 0xCC;                   // Timer2 16-bit register

#define LED P1_bit.BIT3                       // LED definition

//-----------------------------------------------------------------------------
// Global Variables
//-----------------------------------------------------------------------------

long COUNTER;                          // Counter used to measure time between
                                       // toggles of the LED

//-----------------------------------------------------------------------------
// Defines
//-----------------------------------------------------------------------------

#define SYSCLK 24500000                // System Clock in MHz

//-----------------------------------------------------------------------------
// Prototypes
//-----------------------------------------------------------------------------

void OSCILLATOR_Init (void);
void PORT_Init (void);
void Timer2_Init (void);

//-----------------------------------------------------------------------------
// Main
//-----------------------------------------------------------------------------

void main ( void )
{
   PCA0MD &= ~0x40;                    // Disable the watchdog timer

   COUNTER = 0;                        // Initialize timer internal counter

   OSCILLATOR_Init ();                 // Initialize the oscillator
   PORT_Init ();                       // Initialize the crossbar and ports
   Timer2_Init ();                     // Initialize Timer2

   IE_bit.EA = 1;                             // Enable global interrupts
   while (1)                           // Loop forever
   {
      if ( COUNTER == 0 )              // If the counter is zero reload it
      {                                // and toggle the LED
         COUNTER = 500;                // Initialize the counter to be 
                                       // decremented by timer2; time
                                       // in miliseconds
         LED = ~LED;                   // Toggle LED
      }
   }
}

//-----------------------------------------------------------------------------
// Initialization Subroutines
//-----------------------------------------------------------------------------

//-----------------------------------------------------------------------------
// OSCILLATOR_Init
//-----------------------------------------------------------------------------
//
// Return Value : None
// Parameters   : None
//
// This function initializes the system clock to (24.5 Mhz)
//
//-----------------------------------------------------------------------------
void OSCILLATOR_Init (void)
{
   OSCICN = 0x87;                      // Configure internal oscillator for
                                       // its highest frequency
}

//-----------------------------------------------------------------------------
// PORT_Init
//-----------------------------------------------------------------------------
//
// Return Value : None
// Parameters   : None
//
// This function configures the crossbar and GPIO ports.
//
// P1.3   digital   push-pull     LED1
//-----------------------------------------------------------------------------

void PORT_Init (void)
{
   P1MDOUT = 0x08;                     // Force LED pin to be push-pull
   XBR1 = 0x40;                  	   // Enable crossbar, enable weak pull-ups
}

//-----------------------------------------------------------------------------
// Timer2_Init
//-----------------------------------------------------------------------------
//
// Return Value : None
// Parameters   : None
// Description  : Function that initialized the timer2 to create a 1msec time
//                base.
// Note:          Uses the value defined in the SYSCLK. Enables Interrupt.
//-----------------------------------------------------------------------------

void Timer2_Init (void)
{
   CKCON |= 0x10;                      // Timer2 uses the SYSCLK
   TMR2R = -((SYSCLK+500L)/1000);      // Time for 1msec @SYSCLK in both reload
   TMR2 = TMR2R;                       // and timer register
   TMR2CN = 0x04;                      // Timer2 in 16-bit reload timer mode
   IE_bit.ET2 = 1;                            // Enable interrupt in timer2
}

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

//-----------------------------------------------------------------------------
// Timer2_ISR
//-----------------------------------------------------------------------------
//
// Description  : Timer2 Interrupt. Asserted every 1msec and decrements the
//                the counter used to trigger an LED toggle.
//-----------------------------------------------------------------------------

#pragma vector = 0x2B
__interrupt void Timer2_ISR (void)
{
   TMR2CN_bit.TF2H = 0;                           // Reset timer2 interrupt flag
   if ( COUNTER ) {                    // Decrement counter if necessary
      COUNTER--; }
}
                                       
//-----------------------------------------------------------------------------
// End Of File
//-----------------------------------------------------------------------------