高精度测频率

一.捕获法

现给出主要代码CaiJi.c

#include "stm32f10x.h"

#include "CaiJi.h"

//配置系统时钟,使能各外设时钟

void RCC_Configuration(void)

{

SystemInit();

RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE); //时钟配置

RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA | RCC_APB2Periph_GPIOF | RCC_APB2Periph_AFIO , ENABLE );

}

void GPIO_Configuration(void)

{

GPIO_InitTypeDef GPIO_InitStructure;

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6 | GPIO_Pin_7 | GPIO_Pin_8 | GPIO_Pin_9; GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_OD;

GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;

GPIO_Init(GPIOF, &GPIO_InitStructure);

GPIO_SetBits(GPIOF,GPIO_Pin_6 | GPIO_Pin_7 | GPIO_Pin_8 | GPIO_Pin_9);

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_7;

GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;

GPIO_Init(GPIOA, &GPIO_InitStructure);

}

void NVIC_Configuration(void)

{

NVIC_InitTypeDef NVIC_InitStructure;

#ifdef VECT_TAB_RAM

NVIC_SetVectorTable(NVIC_VectTab_RAM, 0x0);

#else

NVIC_SetVectorTable(NVIC_VectTab_FLASH, 0x0);

#endif

NVIC_PriorityGroupConfig(NVIC_PriorityGroup_0);

NVIC_InitStructure.NVIC_IRQChannel = TIM3_IRQn; //NVIC配置

NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;

NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;

NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;

NVIC_Init(&NVIC_InitStructure);

}

//////////////////////////////////////////////////////////////////////////

void TIM3_Configuration(void)//TIM2初始化函数

{

TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;

TIM_ICInitTypeDef TIM_ICInitStructure;

TIM_DeInit(TIM3);

TIM_TimeBaseStructure.TIM_Period = 0xffff;

TIM_TimeBaseStructure.TIM_Prescaler = ?; //此值保密，呵呵，大家自己可以算一下，唯一奥，不然不准

TIM_TimeBaseStructure.TIM_ClockDivision = 0;

TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;

TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure);

TIM_ICInitStructure.TIM_Channel = TIM_Channel_2; //通道选择

TIM_ICInitStructure.TIM_ICPolarity = TIM_ICPolarity_Rising; //上升沿触发

TIM_ICInitStructure.TIM_ICSelection = TIM_ICSelection_DirectTI;//管脚与寄存器对

应关系

TIM_ICInitStructure.TIM_ICPrescaler = TIM_ICPSC_DIV1;

//输入预分频。意思是控制在多少个输入周期做一次捕获，如果

//输入的信号频率没有变，测得的周期也不会变。比如选择4分频，则每四个输入周

//期才做一次捕获，这样在输入信号变化不频繁的情况下，可以减少软件被不断中断的次数。

TIM_ICInitStructure.TIM_ICFilter = 0x0; //滤波设置，经历几个周期跳变认定波形稳定0x0～0xF

TIM_ICInit(TIM3, &TIM_ICInitStructure);

//TIM_PWMIConfig(TIM3, &TIM_ICInitStructure); //根据参数配置TIM外设信息

TIM_SelectInputTrigger(TIM3, TIM_TS_TI2FP2); //选择IC2为始终触发源

TIM_SelectSlaveMode(TIM3, TIM_SlaveMode_Reset);//TIM从模式：触发信号的上升沿重新初始化计数器和触发寄存器的更新事件

TIM_SelectMasterSlaveMode(TIM3, TIM_MasterSlaveMode_Enable); //启动定时器的被动触发

TIM_Cmd(TIM3, ENABLE); //启动TIM2

TIM_ITConfig(TIM3, TIM_IT_CC2, ENABLE); //打开中断使能CC1中断请求

}

stm32f10x_it.c文件

#include "stm32f10x.h"

#include "stm32f10x_it.h"

#include "xpt2046.h"

#include"delay.h"

extern int pinlv;

extern int caiji;

extern int m_timer;

void TIM3_IRQHandler(void)

{

if (TIM_GetITStatus(TIM3, TIM_IT_CC2) == SET)

{

pinlv = TIM_GetCapture2(TIM3);

caiji = 720000000/pinlv;

//caiji=30000;

TIM_ClearITPendingBit(TIM3, TIM_IT_CC2); //清楚TIM的中断待处理位

}

}

二.中断法CaiJi.C文件

#include "stm32f10x.h"

#include "CaiJi.h"

//配置系统时钟,使能各外设时钟

void RCC_Configuration(void)

{

SystemInit();

RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA | RCC_APB2Periph_GPIOF | RCC_APB2Periph_AFIO , ENABLE );

}

void GPIO_Configuration(void)

{

GPIO_InitTypeDef GPIO_InitStructure;

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6 | GPIO_Pin_7 | GPIO_Pin_8 | GPIO_Pin_9; GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_OD;

GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;

GPIO_Init(GPIOF, &GPIO_InitStructure);

GPIO_SetBits(GPIOF,GPIO_Pin_6 | GPIO_Pin_7 | GPIO_Pin_8 | GPIO_Pin_9);

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_7;

GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;

GPIO_Init(GPIOA, &GPIO_InitStructure);

}

void Exit_Configuration()

{

EXTI_InitTypeDef EXTI_InitStructure;

NVIC_InitTypeDef NVIC_InitStructure;

GPIO_EXTILineConfig(GPIO_PortSourceGPIOA, GPIO_PinSource7);

//EXTI_InitStructure.EXTI_Line = EXTI_IMR_MR7;

EXTI_InitStructure.EXTI_Line = EXTI_Line7;

EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt;

EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Rising_Falling;

EXTI_InitStructure.EXTI_LineCmd = ENABLE;

EXTI_Init(&EXTI_InitStructure);

EXTI_GenerateSWInterrupt(EXTI_Line7);

NVIC_PriorityGroupConfig(NVIC_PriorityGroup_0);

NVIC_InitStructure.NVIC_IRQChannel = EXTI9_5_IRQn;

NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;

NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;

NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;

NVIC_Init(&NVIC_InitStructure);

}

void NVIC_Configuration(void)

{

#ifdef VECT_TAB_RAM

NVIC_SetVectorTable(NVIC_VectTab_RAM, 0x0);

#else

NVIC_SetVectorTable(NVIC_VectTab_FLASH, 0x0);

#endif

}

void Timerx_Init2()

{

TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;

//TIM_DeInit(TIM2);

TIM_TimeBaseStructure.TIM_Period =9999;

TIM_TimeBaseStructure.TIM_Prescaler = 7199;

TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1 ;

TIM_TimeBaseStructure.TIM_RepetitionCounter =10 ;//只有高级定时器才有用

TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;

RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);

TIM_TimeBaseInit(TIM2, &TIM_TimeBaseStructure);

// TIM_ClearFlag(TIM2, TIM_FLAG_Update);清除更新标志位

// TIM_ARRPreloadConfig(TIM2, DISABLE);//预装载寄存器的内容被立即传送到影子寄存器

TIM_ITConfig(TIM2, TIM_IT_Update, ENABLE);

TIM_Cmd(TIM2, ENABLE);

NVIC_InitTypeDef NVIC_InitStructure;

NVIC_PriorityGroupConfig(NVIC_PriorityGroup_0);

NVIC_InitStructure.NVIC_IRQChannel = TIM2_IRQn;

NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;

NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;

NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;

NVIC_Init(&NVIC_InitStructure);

}

stm32f10x,it.h文件

#include "stm32f10x.h"

#include "xpt2046.h"

#include"delay.h"

extern int pinlv;

extern int caiji;

extern int m_timer;

void EXTI9_5_IRQHandler(void)

{

if(EXTI_GetITStatus(EXTI_Line7) != RESET)

{

GPIO_SetBits(GPIOF,GPIO_Pin_6 | GPIO_Pin_7 | GPIO_Pin_8 | GPIO_Pin_9);//测试用

pinlv=pinlv+1;

EXTI_ClearITPendingBit(EXTI_Line7);

}

}

void TIM2_IRQHandler(void)

{

if (TIM_GetITStatus(TIM2, TIM_IT_Update) == SET)

{

m_timer=m_timer+1;

if(m_timer==5){

//GPIO_SetBits(GPIOF,GPIO_Pin_6 | GPIO_Pin_7 | GPIO_Pin_8 | GPIO_Pin_9);//测试用

caiji=pinlv;

pinlv=0;

m_timer=0;

//delay_m_timers(1000);

}

TIM_ClearITPendingBit(TIM2, TIM_IT_Update); }

}