[National Technology N32G430] 4. Make a simple and easy-to-use multi-task scheduling system
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【National Technology N32G430】3. Timer - Domestic chip exchange - Electronic Engineering World - Forum (eeworld.com.cn)
[Purpose] When I first learned microcontrollers, delays were all implemented using while blocks, and there was no task scheduling system. Later, because I needed to coordinate several peripherals, I learned state machines, and then I came into contact with operating systems such as freeRTos and RT-hread. This time, when I was learning 51 programming from Diwenping, I learned a very simple and practical multi-task scheduling system. Today, I will transfer it to N32F430 to deepen my impression of task creation, scheduling, and deletion.
1. Following the creation of the timer in the previous article, create a new task.c file as follows:
#include "task.h"
#include <string.h>
#include "main.h"
typedef struct{
u32 countdown;
u32 interval;
TASK_FUNC func_cb;
u8 sta;
}TASK;
#define TASK_STA_IDLE 0x00 //空闲
#define TASK_STA_WAIT 0x01 //等待
#define TASK_TABLE_LEN 8
static TASK task_table[TASK_TABLE_LEN];
static double cur_tick,last_tick,elapsed_tick;
static u16 task_id;
void task_init()
{
cur_tick = 0;
last_tick = 0;
memset((void*)task_table,0,sizeof(task_table));
}
void task_tick(void)
{
cur_tick +=1;
}
//返回任务id，从1开始的，0代表失败
u16 task_create(u32 countdown, u32 interval, TASK_FUNC func_cb)
{
u16 i;
for(i=0; i<TASK_TABLE_LEN; i++)
{
if(task_table[i].sta == TASK_STA_IDLE)
{
task_table[i].countdown = countdown;
task_table[i].interval = interval;
task_table[i].func_cb = func_cb;
task_table[i].sta = TASK_STA_WAIT;
return i+1;
}
}
return 0; //创建失败
}
void task_delete(u16 id)
{
if(id>=1 && id<= TASK_TABLE_LEN)
{
id--;
task_table[id].countdown = 0;
task_table[id].interval = 0;
task_table[id].func_cb = 0;
task_table[id].sta = TASK_STA_IDLE;
}
}
void task_handler(void)
{
elapsed_tick = cur_tick - last_tick;//获得时间差
last_tick = cur_tick;
for(task_id = 0; task_id < TASK_TABLE_LEN; task_id ++)
{
if(task_table[task_id].countdown == 0)
continue;
if(task_table[task_id].countdown>elapsed_tick)
{
task_table[task_id].countdown -= elapsed_tick;
}
else{
task_table[task_id].countdown = 0;
}
if((task_table[task_id].countdown == 0) && (task_table[task_id].sta == TASK_STA_WAIT))
{
if(task_table[task_id].func_cb)
task_table[task_id].func_cb();
if(task_table[task_id].interval)
task_table[task_id].countdown = task_table[task_id].interval;
else
task_table[task_id].sta = TASK_STA_IDLE;
}
}
}
2. Header file: task.h:
#ifndef __TASK_H__
#define __TASK_H__
#include "main.h"
//变量申明
typedef void (*TASK_FUNC)(void);
void task_init(void);
void task_tick(void);
u16 task_create(u32 countdown, u32 interval, TASK_FUNC func_cb);
void task_delete(u16 id);
void task_handler(void);
#endif
3. Import the three files of GPIOdemo:
#include "bsp_led.h" //led驱动
#include "bsp_delay.h" //延时函数
#include "task.h" //任务调度
#include "log.h" //打印函数
4. Main function:
#include "main.h"
#include "task.h"
u16 task1_id,task2_id;
u16 num1,num2;
//任务1
void task1()
{
num1++;
printf("hellow task1 num:%d\r\n",num1);
if(num1>20)
task_delete(task1_id);
}
//任务2
void task2()
{
num2 += 2;
printf("hellow task2 num2:%d\r\n",num2);
if(num2>30)
task_delete(task2_id);
}
/**
*\*\brief Main program
**/
int main(void)
{
log_init();
time6_init();
task_init();
num1 = num2 = 0;
task1_id = task_create(1000,1000,task1); //创建任务1
task2_id = task_create(1000,1000,task2); //创建任务2
while(1)
{
task_handler();
}
}
After compiling and downloading, run the program as shown in the video below. In short, this is a very good task system that is short and concise. It is a good example for learning task creation. I would like to thank Mr. Xiong Jiayu for his detailed explanation.
任务系统
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