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_RAMNVIC_SetVectorTable(NVIC_VectTab_RAM, 0x0);#elseNVIC_SetVectorTable(NVIC_VectTab_FLASH, 0x0);#endifNVIC_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0x0～0xFTIM_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TIM2TIM_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_RAMNVIC_SetVectorTable(NVIC_VectTab_RAM, 0x0);#elseNVIC_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); }}。