main.c

 #include "reg51.h"

 #include "os_cfg.h"

 #define TASK_DELAY0 TIME_PER_SEC/1 //任务执行频度为1Hz

 #define TASK_DELAY1 TIME_PER_SEC/2 //任务执行频度为2Hz

 #define TASK_DELAY2 TIME_PER_SEC/10 //任务执行频度为10Hz

 #define TASK_DELAY3 TIME_PER_SEC/20 //任务执行频度为20Hz

 void (* code task[])() = {task0,task1,task2,task3};

 sbit LED0 = P1^;

 sbit LED1 = P1^;

 sbit LED2 = P1^;

 sbit LED3 = P1^;

 /*main主函数*/

 void main(void)

 {

 unsigned char i;

 os_timer0_init();

 EA = ;    //开总中断

 while()

 {

 for(i=;i<MAX_TASK;i++)

 if (task_delay[i]==) {run(task[i]); break;} //任务优先级调度

 }

 }

 void task0(void)

 {

 LED0 = !LED0;

 task_delay[] = TASK_DELAY0;

 }

 void task1(void)

 {

 LED1 = !LED1;

 task_delay[] = TASK_DELAY1;

 }

 void task2(void)

 {

 LED2 = !LED2;

 task_delay[] = TASK_DELAY2;

 }

 void task3(void)

 {

 static unsigned char state=;

 switch (state)

 {

 case :

 LED3 = !LED3;

 state = ;

 task_delay[] = TASK_DELAY3;

 break;

 case :

 LED3 = !LED3;

 state = ;

 task_delay[] = TASK_DELAY3*;

 break;

 case :

 LED3 = !LED3;

 state = ;

 task_delay[] = TASK_DELAY3*;

 break;

 default:

 break;

 }

 }

 os_cfg.h

 #include "reg51.h"

 #define TIME_PER_SEC 200 //定义任务时钟频率，200Hz

 #define CLOCK 22118400    //定义时钟晶振，单位Hz

 #define MAX_TASK 4    //定义任务数量

 extern void task0(void);

 extern void task1(void);

 extern void task2(void);

 extern void task3(void);

 extern unsigned char task_delay[MAX_TASK];

 extern void run(void (*ptask)());

 extern void os_timer0_init(void);

 os_cfg.c

 #include "os_cfg.h"

 unsigned char task_delay[MAX_TASK];

 //定时器0初始化

 void os_timer0_init(void)

 {

 unsigned char i;

 for(i=;i<MAX_TASK;i++) task_delay[i]=; //赋初值task_delay[0]=0，task_delay[1]=0，task_delay[2]=0，task_delay[3]=0

 TMOD = (TMOD & 0XF0) | 0X01; //定时器0工作在模式1，16Bit定时器模式

 TH0 = (-CLOCK/TIME_PER_SEC/) / ;    //CRY_OSC,TIME_PER_SEC在easycfg.h中配置

 TL0 = (-CLOCK/TIME_PER_SEC/) % ;

 TR0 =;

 ET0 =;    //开启定时器和中断

 }

 // 系统OS定时中断服务

 void os_timer0(void) interrupt

 {

 unsigned char i;

 TH0 = (-CLOCK/TIME_PER_SEC/) / ;    //CRY_OSC,TIME_PER_SEC在easycfg.h中配置

 TL0 = (-CLOCK/TIME_PER_SEC/) % ;

 for(i=;i<MAX_TASK;i++) if(task_delay[i]) task_delay[i]--;    //每节拍对任务延时变量减1 ，减至 0 后，任务就绪。

 }

 void run(void (*ptask)())

 {

 (*ptask)();

 }