STM32——检测输入方波的频率

Main ()
{
#include “stm32f10x.h”
#include “stdio.h”
float Frequency_value;

#define LED_ON GPIO_ResetBits(GPIOA,GPIO_Pin_12)
#define LED_OFF GPIO_SetBits(GPIOA,GPIO_Pin_12)
Void TIM2_Configuart(void)
{
TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2,ENABLE);//使能其所在时钟

 TIM_TimeBaseStructure.TIM_Period = 400-1; //设置重装载寄存器的周期
 TIM_TimeBaseStructure.TIM_Prescaler = 36000-1; //设置时钟频率除数的预分频值
 TIM_TimeBaseStructure.TIM_ClockDivision = 0; //设置时钟分割
 TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up; //向上的计数模式
 TIM_TimeBaseInit(TIM2, &TIM_TimeBaseStructure); //TIM3的初始化
 TIM_ETRClockMode2Config(TIM3,TIM_ExtTRGPSC_OFF,TIM_ExtTRGPolarity_Inverted,0);
 // TIM_ExtTRGPSC_OFF :ETRP 预分频 OFF
 // TIM_ExtTRGPolarity_NonInverted : TIM外部触发极性非翻转：高电平或者上升沿有效
 TIM_SetCounter(TIM3,0);
 TIM_Cmd(TIM2, ENABLE);  //使能TIM3 

}
Void TIM3_Configuart(void)
{
TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3,ENABLE);//使能其所在时钟

 // TIM_Period | TIM_Prescaler 16位
 TIM_TimeBaseStructure.TIM_Period = 0XFFFF - 1; //设置重装载寄存器的周期
 TIM_TimeBaseStructure.TIM_Prescaler = 0X00; //设置时钟频率除数的预分频值
 TIM_TimeBaseStructure.TIM_ClockDivision = 0; //设置时钟分割
 TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up; //向上的计数模式
 TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure); //TIM3的初始化
 TIM_ITConfig(TIM3,TIM_IT_Update,ENABLE ); //TIM3更新中断使能
 TIM_Cmd(TIM2, ENABLE);  //使能TIM2 

}
Void IO_Configuart(void)
{
GPIO_InitTypeDef GPIO_InitStructure;
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA,ENABLE);//使能其所在时钟
GPIO_InitStructure.GPIO_Pin= GPIO_Pin_12 //设置引脚
GPIO_InitStructure.GPIO_Mode=GPIO_Mode_Out_PP; //设置模式
GPIO_InitStructure.GPIO_Speed=GPIO_Speed_50MHz;//设置速度
GPIO_Init(GPIOA,&GPIO_InitStructure);

}
Void NVIC_ Configuart(void)
{
NVIC_InitTypeDef NVIC_InitStructure;
NVIC_InitStructure.NVIC_IRQChannel = TIM2_IRQn; //TIM2中断
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0; //先占优先0级
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1; //从占优先3级
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; //IRQ通道使能
NVIC_Init(&NVIC_InitStructure); //初始化NVIC寄存器
}
void USART1_Configuart(void)
{
GPIO_InitTypeDef GPIO_InitStructure;
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA,ENABLE);

GPIO_InitStructure.GPIO_Pin= GPIO_Pin_9 | GPIO_Pin_10; //设置引脚TX | RX
GPIO_InitStructure.GPIO_Mode=GPIO_Mode_AF_PP; //设置串行通信模式
GPIO_InitStructure.GPIO_Speed=GPIO_Speed_50MHz;//设置速度
GPIO_Init(GPIOA,&GPIO_InitStructure);

USART_InitTypeDef USART_InitStructure;
RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1,ENABLE);

USART_InitStructure.USART_BaudRate = 115200;
USART_InitStructure.USART_WordLength = USART_WordLength_8b;
USART_InitStructure.USART_StopBits = USART_StopBits_1;
USART_InitStructure.USART_Parity = USART_Parity_No;
USART_InitStructure.USART_HardWareFlowControl = USART_HardWareFlowControl_None;//无流控
USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;//使能发送和接收
USART_Init(USART1,&USART_InitStructure);
USART_Cmd(USART1,ENABLE);
}
int fputc(int ch, FILE *f)
{
USART_SendData(USART1, (unsigned char) ch);
while (USART_GetFlagStatus(USART1, USART_FLAG_TC) == RESET) {}
return ch;
}
void Delay_ms(void)
{
long int i,j;
for (i = 0; i < 10000; i++)
for (j = 0; j < 1000; j++);
}

int main(void)
{
TIM3_Configuart();
TIM2_Configuart();
IO_Configuart();
NVIC_ Configuart();
USART1_Configuart();

While(1)
{
LED_ON;
printf("\nHello!\n");
printf("\n%f",Frequency_value);
Delay_ms();
LED_OFF;
Delay_ms();
}
Return 0;
}
/stm32f10x_it.c********/
//定时器3中断服务程序
void TIM3_IRQHandler(void) //TIM3中断
{
if (TIM_GetITStatus(TIM2, TIM_IT_Update) != RESET) //检查TIM3更新中断发生与否
{
TIM_ClearITPendingBit(TIM2, TIM_IT_Update ); //清除TIMx更新中断标志
Frequency_value = TIM_GetCounter(TIM3)/0.2; //周期200ms
TIM_SetCounter(TIM3,0);//从0开始计数字
}
/stm32f10x_it.c********/
/stm32f10x_it.h********/
Extern float Frequency_value;
void TIM2_IRQHandler(void);
/stm32f10x_it.h********/