[Jiangsu University of Science and Technology Automation Association stm32F103c8t6] Notes [Initial 32 MCU and TIM timing interrupt initialization parameter configuration]

六、TIM定时中断

TIM基本结构---------------------------------编写原理 如图中所述

• 72M对7200进行分频,得到的就是10K的计数频率 ,在10kfrequency count down10000个数就是1s

1、RCC开启时钟

This basically every code is the first step,不用多想,在这里打开时钟后,The base clock of the timer and the working clock of the entire peripheral will be turned on at the same time

2、选择时基单元的时钟源

对于定时中断,We choose the internal clock source

3、配置时基单元

Including the prescaler here、自动重装器、计数模式等等,These parameters can be configured with a structure

4、配置输出中断控制,允许更新中断输出到NVIC

5、配置NVIC

在NVIC中打开定时器中断的通道,并分配一个优先级

6、运行控制

——————————————————————————————————————整个模块配置完成后,我们还需要使能一下计数器,要不然计数器是不会运行的,当定时器使能后,计数器就会开始计数了,当计数器更新时,触发中断,Finally, we write a timer interrupt function,In this way, the interrupt function will be automatically executed every once in a while,好,These are the general ideas of how we initialize the timer

The following is the code routine of the Jiangke University Automation Association：

#include "stm32f10x.h" // Device header

//extern uint16_t Num; //引用其他文件(主函数)的Num变量

void Timer_Init(void)
{
    
//开启时钟

	RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);//TIM2是APB1总线上的外设
	
//选择时基单元的时钟 

	TIM_InternalClockConfig(TIM2); //tim.h--->选择内部时钟,可以不写,因为定时器上电后默认选择内部时钟
	
//初始化时基单元 类似于GPIO的初始化
	TIM_TimeBaseInitTypeDef TIM_TimeBaseInitStructure; //配置时基单元
	TIM_TimeBaseInitStructure.TIM_ClockDivision = TIM_CKD_DIV1; //指定时钟分频 ,1分频 影响不大,Jump to definition can also be changed to 2、4分频 
	TIM_TimeBaseInitStructure.TIM_CounterMode = TIM_CounterMode_Up;//向上计数（And down、Three kinds of centers count it）
	TIM_TimeBaseInitStructure.TIM_Period = 10000 - 1; //周期 ARR自动重装器的值//有1的误差//形成CNT计数 重装值
	TIM_TimeBaseInitStructure.TIM_Prescaler = 7200 - 1;  //PSC预分频器的值 10k的计数频率 计10000的数//有1的误差//形成CNT计数 倍数变化
	TIM_TimeBaseInitStructure.TIM_RepetitionCounter = 0; //重复计数器的值 //高级定时器才有 Generic timer here 不用
	TIM_TimeBaseInit(TIM2, &TIM_TimeBaseInitStructure);//这里选择的是TIM2,注意下面的NVIC通道
	
	TIM_ClearFlag(TIM2, TIM_FLAG_Update);//TIM_TimeBaseInitThere is an explanation,Interrupts are initialized at the same time,At this time, you need to manually clear the update interrupt flag bit,防止reset直接到1
	
//使能更新中断,Interrupt output control

	TIM_ITConfig(TIM2, TIM_IT_Update, ENABLE); //使能中断 update 更新中断
	

//NVIC
	
	NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2); //优先级分组
	
	NVIC_InitTypeDef NVIC_InitStructure;
	NVIC_InitStructure.NVIC_IRQChannel = TIM2_IRQn; //TIM2在NVIC里的通道
	NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
	NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 2;
	NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;
	NVIC_Init(&NVIC_InitStructure);
	
//启动定时器,运行控制

	TIM_Cmd(TIM2, ENABLE); //启动定时器,This will allow the timer to start working,An interrupt is triggered when an update occurs
}

//——————————————————————————————————————————————————————————————————————————————————————————At this point, the timer initialization code is completed

//Next, write the interrupt function

/* void TIM2_IRQHandler(void) //startup_stm32f10x_md.s------->定时器2 的中断函数 { if (TIM_GetITStatus(TIM2, TIM_IT_Update) == SET)//See update interrupt flag bit { //Num++; TIM_ClearITPendingBit(TIM2, TIM_IT_Update);//清零标志位 } } */

The external clock is used as a counter

外部中断GPIO的配置,pull-up,Floating is not good

*********************************************************************

#include "stm32f10x.h" // Device header

//PA0 TIM2的ETR引脚
void Timer_Init(void)
{
    
	RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);
	RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);//External interrupt to be configuredGPIO
	
	GPIO_InitTypeDef GPIO_InitStructure;
	GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU;
	GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0;
	GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
	GPIO_Init(GPIOA, &GPIO_InitStructure);
	
	TIM_ETRClockMode2Config(TIM2, TIM_ExtTRGPSC_OFF, TIM_ExtTRGPolarity_NonInverted, 0x00);//通过ETRpin's external clock mode2配置
	//TIM_ExtTRGPSC_OFF No frequency division is required //TIM_ExtTRGPolarity_NonInverted极性,Active high or rising edge //0x00No filter needed
	TIM_TimeBaseInitTypeDef TIM_TimeBaseInitStructure;
	TIM_TimeBaseInitStructure.TIM_ClockDivision = TIM_CKD_DIV1;
	TIM_TimeBaseInitStructure.TIM_CounterMode = TIM_CounterMode_Up;
	TIM_TimeBaseInitStructure.TIM_Period = 10 - 1; //从0计到9　//CNT计数器的值
	TIM_TimeBaseInitStructure.TIM_Prescaler = 1 - 1;//No frequency division is required //If there is a prescaler Just block it a few times and add it once　　//被分频
	TIM_TimeBaseInitStructure.TIM_RepetitionCounter = 0;
	TIM_TimeBaseInit(TIM2, &TIM_TimeBaseInitStructure);
	
	TIM_ClearFlag(TIM2, TIM_FLAG_Update);
	TIM_ITConfig(TIM2, TIM_IT_Update, ENABLE);
	
	NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);
	
	NVIC_InitTypeDef NVIC_InitStructure;
	NVIC_InitStructure.NVIC_IRQChannel = TIM2_IRQn;
	NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
	NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 2;
	NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;
	NVIC_Init(&NVIC_InitStructure);
	
	TIM_Cmd(TIM2, ENABLE);
}

uint16_t Timer_GetCounter(void)
{
    
	return TIM_GetCounter(TIM2);
}

/* void TIM2_IRQHandler(void) { if (TIM_GetITStatus(TIM2, TIM_IT_Update) == SET) { TIM_ClearITPendingBit(TIM2, TIM_IT_Update); } } */

七、跨越不同.c文件的变量

Use the same variable across files,An error will be reported if it is not handled properly

解决方法
1、For example, the variable inside the interrupt,If you want to use it in the main function,in the file that uses the variable（中断文件）的上面,用externDeclare the variables to be used
比如：extern uint16_t Num;
2、Copy and paste the interrupt function below the main function,Then comment out the interrupt function in the interrupt,put it where it is used,这样更方便