Introduce the configuration method of the STM32F407 basic timer, respectively introduce the polling mode and the interrupt mode using the timer to complete the timing.
【1】Timer introduction
The timer-related chapters are in chapters 14, 15, 16, and 17 of the STM32F4xx reference manual.
【2】Basic timer configuration example
Add a Timer.c file, the code is as follows
#include "timer.h"
/*
函数功能:基本定时器7初始化配置
函数形参:
psc :预分频系数
arr :重载值
说明:定时器的视频频率为84MHZ ,是APB1时钟频率的2倍
*/
void Time7_InitConfig(u16 psc,u16 arr)
{
/*1. 开时钟*/
RCC->APB1ENR|=1<<5; //开启定时器7的时钟
RCC->APB1RSTR|=1<<5; //开启复位时钟
RCC->APB1RSTR&=~(1<<5);//关闭
/*2. 配置定时器的核心寄存器*/
TIM7->PSC=psc-1; //预分频
/*计数器的时钟频率CK_CNT等于fCK_PSC/(PSC[15:0]+1)*/
TIM7->ARR=arr; //重装载寄存器
TIM7->CR1|=1<<0; //使能计数器
}
The code in the Main.c file is as follows
#include "stm32f4xx.h" // Device header
#include "led.h"
#include "delay.h"
#include "key.h"
#include "usart.h"
#include "sys.h"
#include "exti.h"
#include "timer.h"
int main(void)
{
LED_Init();
KEY_Init();
USART1_Init(84,115200);
KEY_EXTI_Init();
/*
1/84000000得到定时器加的1的时间单位us
1/84000得到定时器加的1的时间单位ms
1/84得到定时器加的1的时间单位s =0.0119047619047619
*/
Time7_InitConfig(84,1000); //定时器7初始化
/*
分频84,最终频率1HMZ 计数器CNT+1的时间是1us
*/
while(1)
{
if(TIM7->SR&1<<0) //判断时间是否到达
{
TIM7->SR&=~(1<<0); //清除标志位
LED0=!LED0;
LED1=!LED1;
}
}
}
【3】Basic timer interrupt configuration example
Add the following code to the timer.c file
#include "timer.h"
/*
函数功能:基本定时器7初始化配置
函数形参:
psc :预分频系数
arr :重载值
说明:定时器的视频频率为84MHZ ,是APB1时钟频率的2倍
*/
void Time7_InitConfig(u16 psc,u16 arr)
{
/*1. 开时钟*/
RCC->APB1ENR|=1<<5; //开启定时器7的时钟
RCC->APB1RSTR|=1<<5; //开启复位时钟
RCC->APB1RSTR&=~(1<<5);//关闭
/*2. 配置定时器的核心寄存器*/
TIM7->DIER|=1<<0; //开启中断
SetNVICPriorityGrouping(TIM7_IRQn,1,1); //设置中断优先级
TIM7->PSC=psc-1; //预分频
/*计数器的时钟频率CK_CNT等于fCK_PSC/(PSC[15:0]+1)*/
TIM7->ARR=arr; //重装载寄存器
TIM7->CR1|=1<<0; //使能计数器
}
/*
函数功能:定时器中断服务函数
*/
void TIM7_IRQHandler(void)
{
TIM7->SR=0x0;
LED0=!LED0;
LED1=!LED1;
}
Main.c file code is as follows
#include "stm32f4xx.h" // Device header
#include "led.h"
#include "delay.h"
#include "key.h"
#include "usart.h"
#include "sys.h"
#include "exti.h"
#include "timer.h"
int main(void)
{
LED_Init();
KEY_Init();
USART1_Init(84,115200);
KEY_EXTI_Init();
/*
1/84000000得到定时器加的1的时间单位us
1/84000得到定时器加的1的时间单位ms
1/84得到定时器加的1的时间单位s =0.0119047619047619
*/
Time7_InitConfig(84,65000); //定时器7初始化
/*
分频84,最终频率1HMZ 计数器CNT+1的时间是1us
*/
while(1)
{
}
}