定时器中断
添加Timer.c和Timer.h文件

初始化

1.RCC开启时钟(TIM2是APB1总线的外设)
2.选择时基单元的时钟源,定时中断选择内部时钟源
3.配置时基单元,用一个结构体
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,并分配优先级
6.运行控制,模块配置完成后,还需要使能计数器。定时器使能后,计数器开始计数,当计数器更新时,触发中断,最后写一个定时器的中断函数
c
void TIM_DeInit(TIM_TypeDef* TIMx);
回复缺省配置
c
void TIM_TimeBaseInit(TIM_TypeDef* TIMx, TIM_TimeBaseInitTypeDef* TIM_TimeBaseInitStruct);
时基单元初始化
c
void TIM_TimeBaseStructInit(TIM_TimeBaseInitTypeDef* TIM_TimeBaseInitStruct);
把结构体变量赋一个默认值
c
void TIM_Cmd(TIM_TypeDef* TIMx, FunctionalState NewState);
使能计数器
NewState,新状态,使能/失能
c
void TIM_ITConfig(TIM_TypeDef* TIMx, uint16_t TIM_IT, FunctionalState NewState);
使能中断输出信号
c
void TIM_InternalClockConfig(TIM_TypeDef* TIMx);
//选择内部时钟
void TIM_ITRxExternalClockConfig(TIM_TypeDef* TIMx, uint16_t TIM_InputTriggerSource);
//选择ITRx其他定时器的时钟
void TIM_TIxExternalClockConfig(TIM_TypeDef* TIMx, uint16_t TIM_TIxExternalCLKSource,uint16_t TIM_ICPolarity, uint16_t ICFilter);
//选择TIx捕获通道的时钟
//TIM_TIxExternalCLKSource:选择TIx具体的某个引脚
//TIM_ICPolarity:输入极性
//ICFilter:滤波器
void TIM_ETRClockMode1Config(TIM_TypeDef* TIMx, uint16_t TIM_ExtTRGPrescaler, uint16_t TIM_ExtTRGPolarity,uint16_t ExtTRGFilter);
//选择ETR通过外部时钟模式1输入的时钟
//TIM_ExtTRGPrescaler:外部触发预分频器
void TIM_ETRClockMode2Config(TIM_TypeDef* TIMx, uint16_t TIM_ExtTRGPrescaler, uint16_t TIM_ExtTRGPolarity, uint16_t ExtTRGFilter);
//选择ETR通过外部时钟模式2输入的时钟
void TIM_ETRConfig(TIM_TypeDef* TIMx, uint16_tTIM_ExtTRGPrescaler, uint16_t TIM_ExtTRGPolarity,uint16_t ExtTRGFilter);
//单独用来配置ETR引脚的预分频器,极性,滤波器
c
void TIM_PrescalerConfig(TIM_TypeDef* TIMx, uint16_t Prescaler, uint16_t TIM_PSCReloadMode);
单独写预分频值
Prescaler:预分频值
TIM_PSCReloadMode:模式(听从安排,在更新时间后生效;手动产生更新事件,立即生效)
c
void TIM_CounterModeConfig(TIM_TypeDef* TIMx, uint16_t TIM_CounterMode);
改变计数器的计数模式
TIM_CounterMode:新的计数器模式
c
void TIM_ARRPreloadConfig(TIM_TypeDef* TIMx, FunctionalState NewState);
自动重装寄存器预装功能配置
c
void TIM_SetCounter(TIM_TypeDef* TIMx, uint16_t Counter);
给计数器写入一个值
c
void TIM_SetAutoreload(TIM_TypeDef* TIMx, uint16_t Autoreload);
给自动重装寄存器写入一个值
c
uint16_t TIM_GetCounter(TIM_TypeDef* TIMx);
获取当前计数器的值
c
uint16_t TIM_GetPrescaler(TIM_TypeDef* TIMx);
获取当前的预分频器的值
在该程序中
如果想跨文件使用变量Num,解决方法两种:
1.用extern声明一下要用的变量
2.将中断函数放到主函数后面
问题:
c
void TIM_TimeBaseInit(TIM_TypeDef* TIMx, TIM_TimeBaseInitTypeDef* TIM_TimeBaseInitStruct)
/* Generate an update event to reload the Prescaler and the Repetition counter
values immediately */
//让值立即起作用,手动生成一个更新事件,但同时,更新事件和更新中断同时发生,更新中断会置中断标志位,所以一旦初始化完,更新中断就会立即进入,所以一上电就会立即进中断
解决方案:
c
TIM_ClearFlag(TIM2 , TIM_FLAG_Update);
手动把更新中断标志位清除一下
Tim.c:
c
void Timer_Init(void)
{
RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2 , ENABLE);
TIM_InternalClockConfig(TIM2);
TIM_TimeBaseInitTypeDef TIM_TimeBaseInitStructure;
TIM_TimeBaseInitStructure.TIM_ClockDivision = TIM_CKD_DIV1 ;
TIM_TimeBaseInitStructure.TIM_CounterMode = TIM_CounterMode_Up;
TIM_TimeBaseInitStructure.TIM_Period = 10000 - 1;
TIM_TimeBaseInitStructure.TIM_Prescaler = 7200 - 1;
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);
}
main.c:
c
uint16_t Num;
int main(void)
{
OLED_Init();
Timer_Init();
OLED_ShowString(1, 1, "Num:");
while(1)
{
OLED_ShowNum(1, 5, Num,5);
OLED_ShowNum(2, 5, TIM_GetCounter(TIM2), 5);
}
}
void TIM2_IRQHandler(void)
{
if(TIM_GetITStatus(TIM2, TIM_IT_Update) == SET)
{
Num++;
TIM_ClearITPendingBit(TIM2 , TIM_IT_Update);
}
}
定时器外部时钟
当使用外部时钟:
连接到PA0上时
TIM_ETRClockModexConfig:
Mode 1:一个只有踩下油门踏板(高电平)才会转动的发动机。
Mode 2:一个每点火一次(边沿)就转动一下的发动机,无论油门踏板是否踩着
滤波器选择:
使用浮空输入情况:
外部输入信号功率很小,内部上拉电阻可能会影响到这个输入信号

c
TIM_TimeBaseInitStructure.TIM_Prescaler = 1 - 1;
没有预分频,每次遮挡CNT都加1
如果有预分频,遮挡几次才会加一次
Timer.c:
c
void Timer_Init(void)
{
RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2 , ENABLE);
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);
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);
TIM_TimeBaseInitTypeDef TIM_TimeBaseInitStructure;
TIM_TimeBaseInitStructure.TIM_ClockDivision = TIM_CKD_DIV1 ;
TIM_TimeBaseInitStructure.TIM_CounterMode = TIM_CounterMode_Up;
TIM_TimeBaseInitStructure.TIM_Period = 10 - 1;
TIM_TimeBaseInitStructure.TIM_Prescaler = 1 - 1;
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);
}
main.c:
c
uint16_t Num;
int main(void)
{
OLED_Init();
Timer_Init();
OLED_ShowString(1, 1, "Num:");
OLED_ShowString(1, 1, "CNT:");
while(1)
{
OLED_ShowNum(1, 5, Num,5);
OLED_ShowNum(2, 5, Timer_GetCounter(),5);
}
}
void TIM2_IRQHandler(void)
{
if(TIM_GetITStatus(TIM2, TIM_IT_Update) == SET)
{
Num++;
TIM_ClearITPendingBit(TIM2 , TIM_IT_Update);
}
}
注:本文来源b站江协课程,为笔记