blinky.c

来自「8051试验程序 基础教材」· C语言 代码 · 共 116 行

//------------------------------------------------------------------------------------
// Blinky.c
//------------------------------------------------------------------------------------
// Copyright (C) 2005 Silicon Laboratories, Inc.
//
// AUTH: BW
// DATE: 4 SEP 01
//
// This program flashes the green LED on the C8051F020 target board about five times
// a second using the interrupt handler for Timer3.
// Target: C8051F02x
//
//

//------------------------------------------------------------------------------------
// Includes
//------------------------------------------------------------------------------------
#include <ioC8051f020.h>                    // SFR declarations

//------------------------------------------------------------------------------------
// 16-bit SFR Definitions for 'F02x
//------------------------------------------------------------------------------------

__sfr __no_init volatile unsigned short DP       @ 0x82;                    // data pointer
__sfr __no_init volatile unsigned short TMR3RL   @ 0x92;                    // Timer3 reload value
__sfr __no_init volatile unsigned short TMR3     @ 0x94;                    // Timer3 counter
__sfr __no_init volatile unsigned short ADC0     @ 0xbe;                    // ADC0 data
__sfr __no_init volatile unsigned short ADC0GT   @ 0xc4;                    // ADC0 greater than window
__sfr __no_init volatile unsigned short ADC0LT   @ 0xc6;                    // ADC0 less than window
__sfr __no_init volatile unsigned short RCAP2    @ 0xca;                    // Timer2 capture/reload
__sfr __no_init volatile unsigned short T2       @ 0xcc;                    // Timer2
__sfr __no_init volatile unsigned short RCAP4    @ 0xe4;                    // Timer4 capture/reload
__sfr __no_init volatile unsigned short T4       @ 0xf4;                    // Timer4
__sfr __no_init volatile unsigned short DAC0     @ 0xd2;                    // DAC0 data
__sfr __no_init volatile unsigned short DAC1     @ 0xd5;                    // DAC1 data

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

#define SYSCLK 2000000                    // approximate SYSCLK frequency in Hz

#define LED P1_bit.P16                         // green LED: '1' = ON; '0' = OFF
#define EA IE_bit.EA

//------------------------------------------------------------------------------------
// Function PROTOTYPES
//------------------------------------------------------------------------------------
void PORT_Init (void);
void Timer3_Init (int counts);
__interrupt void Timer3_ISR (void);

//------------------------------------------------------------------------------------
// MAIN Routine
//------------------------------------------------------------------------------------
void main (void) {

   // disable watchdog timer
   WDTCN = 0xde;
   WDTCN = 0xad;
	
   PORT_Init ();
   Timer3_Init (SYSCLK / 12 / 10);        // Init Timer3 to generate interrupts
                                          // at a 10Hz rate.

   EA = 1;											// enable global interrupts

   while (1) {                            // spin forever
   }
}

//------------------------------------------------------------------------------------
// PORT_Init
//------------------------------------------------------------------------------------
//
// Configure the Crossbar and GPIO ports
//
void PORT_Init (void)
{
   XBR2    = 0x40;                     // Enable crossbar and weak pull-ups
   P1MDOUT |= 0x40;                    // enable P1.6 (LED) as push-pull output
}

//------------------------------------------------------------------------------------
// 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
   TMR3RL  = -counts;                  // Init reload values
   TMR3    = 0xffff;                   // set to reload immediately
   EIE2   |= 0x01;                     // enable Timer3 interrupts
   TMR3CN |= 0x04;                     // start Timer3
}

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

//------------------------------------------------------------------------------------
// Timer3_ISR
//------------------------------------------------------------------------------------
// This routine changes the state of the LED whenever Timer3 overflows.
//
#pragma vector=0x73 //interrupt 14
__interrupt void Timer3_ISR (void)
{
   TMR3CN &= ~(0x80);                     // clear TF3
   LED = ~LED;                            // change state of LED
}