stm32 测频率（1HZ

2024-07-14 16:30| 来源: 网络整理| 查看: 265

stm32 测频率外部中断（低频）输入捕获模式（中高频）外部计数器模式（高频）准备电赛的过程中，尝试了几种测量频率的方法，也参考了一些博主，没有一种可以测量范围很广的方法，那就都尝试一下，需要什么就用什么吧。

下面的代码都是我运行成功的，可以测量

平台：stm32F407

外部中断（低频）

第一个想到的就是外部中断，也是最简单的方式，在每一个上升沿或者下降沿进入一次中断，定时统计进入中断的次数，即可算出频率，如果需要计算出占空比，可以在用另外一个定时器测量上升沿和下降沿的时间就可以啦，下面贴出外部中断和定时器的代码，在低频时很不错，但是50KHZ之后太不行了，误差好大，频繁进入中断，只能测测低频啦

下面展示一些内联代码片。 TIM4_Int_Init(10000-1,8400-1);//*外部中断测频率 PA0

// A code block /** * @brief 外部中断测频率 * @param * @retval */ void TIM4_Int_Init(u16 arr,u16 psc) { TIM_TimeBaseInitTypeDef TIM_TimeBaseInitStructure; NVIC_InitTypeDef NVIC_InitStructure; RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM4,ENABLE); ///使能TIM3时钟 TIM_TimeBaseInitStructure.TIM_Period = arr; //自动重装载值 TIM_TimeBaseInitStructure.TIM_Prescaler=psc; //定时器分频 TIM_TimeBaseInitStructure.TIM_CounterMode=TIM_CounterMode_Up; //向上计数模式 TIM_TimeBaseInitStructure.TIM_ClockDivision=TIM_CKD_DIV1; TIM_TimeBaseInit(TIM4,&TIM_TimeBaseInitStructure);//初始化TIM2 TIM_ITConfig(TIM4,TIM_IT_Update,ENABLE); //允许定时器2更新中断 TIM_Cmd(TIM4,ENABLE); //使能定时器3 NVIC_InitStructure.NVIC_IRQChannel=TIM4_IRQn; //定时器3中断 NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority=0x01; //抢占优先级1 NVIC_InitStructure.NVIC_IRQChannelSubPriority=0x03; //子优先级3 NVIC_InitStructure.NVIC_IRQChannelCmd=ENABLE; NVIC_Init(&NVIC_InitStructure); } void TIM4_IRQHandler(void) { if(TIM_GetITStatus(TIM4,TIM_IT_Update)==SET) //溢出中断 { LCD_ShowNum(60,60,freq,8,16); freq=0; } TIM_ClearITPendingBit(TIM4,TIM_IT_Update); //清除中断标志位 } // An highlighted block //外部中断初始化程序 void EXTIX_Init(void) { NVIC_InitTypeDef NVIC_InitStructure; EXTI_InitTypeDef EXTI_InitStructure; KEY_Init(); //按键对应的IO口初始化 RCC_APB2PeriphClockCmd(RCC_APB2Periph_SYSCFG, ENABLE);//使能SYSCFG时钟 GPIO_InitTypeDef GPIO_InitStructure; RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE); GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0; GPIO_InitStructure.GPIO_Mode=GPIO_Mode_IN; GPIO_InitStructure.GPIO_Speed=GPIO_High_Speed; GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_DOWN ; GPIO_Init(GPIOA, &GPIO_InitStructure); SYSCFG_EXTILineConfig(EXTI_PortSourceGPIOA, EXTI_PinSource0); /* 配置EXTI_Line0 */ EXTI_InitStructure.EXTI_Line = EXTI_Line0;//LINE0 EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt;//中断事件 EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Rising; //上升沿触发 EXTI_InitStructure.EXTI_LineCmd = ENABLE;//使能LINE0 EXTI_Init(&EXTI_InitStructure);//配置 NVIC_InitStructure.NVIC_IRQChannel = EXTI0_IRQn;//外部中断0 NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0x02;//抢占优先级2 NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0x02;//子优先级2 NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;//使能外部中断通道 NVIC_Init(&NVIC_InitStructure);//配置 } //外部中断0服务程序 void EXTI0_IRQHandler(void) { // if(GPIO_ReadInputDataBit(GPIOA,GPIO_Pin_0) == 1){ // GPIO_ResetBits(GPIOA,GPIO_Pin_6 | GPIO_Pin_7); // } freq++; EXTI_ClearITPendingBit(EXTI_Line0); //清除LINE0上的中断标志位 } 输入捕获模式（中高频）

既然是测频率，自然会想到定时器的输入捕获模式，本以为这个还不错，但是超过100KHZ误差就很大了，测中高频是可以的。这个我参考了野火的程序输入捕获可以对输入信号的上升沿、下降沿、双边沿进行捕获，用于测量脉宽、频率、占空比当相应的 ICx 信号检测到跳变沿后，将使用捕获/比较寄存器(TIMx_CCRx)来锁存计数器的值。通过检测 TIMx_CHx 上的边沿信号，在边沿信号发生跳变（比如上升沿/下降沿）的时候，将当前定时器的值（TIMx_CNT）存放到对应的通道的捕获/比较寄存（TIMx_CCRx）里面，完成一次捕获。同时还可以配置捕获时是否触发中断/DMA 等。通过对上升沿下降沿捕获的值来计算需要的值下面展示一些内联代码片。 // TIM8_Configuration();//输入捕获模式测频率

// A code block ** * @brief 定时器输入捕获模式 * @param * @retval */ /** * @brief 配置TIM复用输出PWM时用到的I/O * @param 无 * @retval 无 */ static void TIMx_GPIO_Config(void) { /*定义一个GPIO_InitTypeDef类型的结构体*/ GPIO_InitTypeDef GPIO_InitStructure; /*开启LED相关的GPIO外设时钟*/ RCC_AHB1PeriphClockCmd (GENERAL_OCPWM_GPIO_CLK, ENABLE); RCC_AHB1PeriphClockCmd (ADVANCE_ICPWM_GPIO_CLK, ENABLE); /* 定时器复用引脚 */ GPIO_PinAFConfig(GENERAL_OCPWM_GPIO_PORT,GENERAL_OCPWM_PINSOURCE,GENERAL_OCPWM_AF); GPIO_PinAFConfig(ADVANCE_ICPWM_GPIO_PORT,ADVANCE_ICPWM_PINSOURCE,ADVANCE_ICPWM_AF); /* 通用定时器PWM输出引脚 */ GPIO_InitStructure.GPIO_Pin = GENERAL_OCPWM_PIN; GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF; GPIO_InitStructure.GPIO_OType = GPIO_OType_PP; GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL; GPIO_InitStructure.GPIO_Speed = GPIO_Speed_100MHz; GPIO_Init(GENERAL_OCPWM_GPIO_PORT, &GPIO_InitStructure); /* 高级控制定时器PWM输入捕获引脚 */ GPIO_InitStructure.GPIO_Pin = ADVANCE_ICPWM_PIN; GPIO_Init(ADVANCE_ICPWM_GPIO_PORT, &GPIO_InitStructure); } /** * @brief 高级控制定时器 TIMx,x[1,8]中断优先级配置 * @param 无 * @retval 无 */ static void TIMx_NVIC_Configuration(void) { NVIC_InitTypeDef NVIC_InitStructure; // 设置中断组为0 NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2); // 设置中断来源 NVIC_InitStructure.NVIC_IRQChannel = ADVANCE_TIM_IRQn; // 设置抢占优先级 NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0; // 设置子优先级 NVIC_InitStructure.NVIC_IRQChannelSubPriority = 3; NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; NVIC_Init(&NVIC_InitStructure); NVIC_InitStructure.NVIC_IRQChannel = TIM5_IRQn; NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1; NVIC_Init(&NVIC_InitStructure); } static void TIM_PWMOUTPUT_Config(void) { TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure; TIM_OCInitTypeDef TIM_OCInitStructure; // 开启TIMx_CLK,x[2,3,4,5,12,13,14] RCC_APB1PeriphClockCmd(GENERAL_TIM_CLK, ENABLE); /* 累计 TIM_Period个后产生一个更新或者中断*/ //当定时器从0计数到9999，即为10000次，为一个定时周期 TIM_TimeBaseStructure.TIM_Period = 10000-1; // 通用定时器2时钟源TIMxCLK = HCLK/2=84MHz // 设定定时器频率为=TIMxCLK/(TIM_Prescaler+1)=100KHz TIM_TimeBaseStructure.TIM_Prescaler = 840-1; // 采样时钟分频 TIM_TimeBaseStructure.TIM_ClockDivision=TIM_CKD_DIV1; // 计数方式 TIM_TimeBaseStructure.TIM_CounterMode=TIM_CounterMode_Up; // 初始化定时器TIMx, x[1,8] TIM_TimeBaseInit(GENERAL_TIM, &TIM_TimeBaseStructure); /* PWM输出模式配置 */ /* 配置为PWM模式1 */ TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1; TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable; /* PWM脉冲宽度 */ TIM_OCInitStructure.TIM_Pulse = 3000-1; TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High; /* 使能通道1 */ TIM_OC1Init(GENERAL_TIM, &TIM_OCInitStructure); /*使能通道1重载*/ TIM_OC1PreloadConfig(GENERAL_TIM, TIM_OCPreload_Enable); // 使能定时器 TIM_Cmd(GENERAL_TIM, ENABLE); } static void TIM_PWMINPUT_Config(void) { TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure; TIM_ICInitTypeDef TIM_ICInitStructure; // 开启TIMx_CLK,x[1,8] RCC_APB2PeriphClockCmd(ADVANCE_TIM_CLK, ENABLE); TIM_TimeBaseStructure.TIM_Period = 0xFFFF-1; // 高级控制定时器时钟源TIMxCLK = HCLK=168MHz // 设定定时器频率为=TIMxCLK/(TIM_Prescaler+1)=100KHz TIM_TimeBaseStructure.TIM_Prescaler = 168-1; // 计数方式 TIM_TimeBaseStructure.TIM_CounterMode=TIM_CounterMode_Up; // 初始化定时器TIMx, x[1,8] TIM_TimeBaseInit(ADVANCE_TIM, &TIM_TimeBaseStructure); /* IC1捕获：上升沿触发 TI1FP1 */ TIM_ICInitStructure.TIM_Channel = ADVANCE_IC1PWM_CHANNEL; TIM_ICInitStructure.TIM_ICPolarity = TIM_ICPolarity_Rising; TIM_ICInitStructure.TIM_ICSelection = TIM_ICSelection_DirectTI; TIM_ICInitStructure.TIM_ICPrescaler = TIM_ICPSC_DIV1; TIM_ICInitStructure.TIM_ICFilter = 0x0; TIM_PWMIConfig(ADVANCE_TIM, &TIM_ICInitStructure); /* IC2捕获：下降沿触发 TI1FP2 */ TIM_ICInitStructure.TIM_Channel = ADVANCE_IC2PWM_CHANNEL; TIM_ICInitStructure.TIM_ICPolarity = TIM_ICPolarity_Falling; TIM_ICInitStructure.TIM_ICSelection = TIM_ICSelection_IndirectTI; TIM_ICInitStructure.TIM_ICPrescaler = TIM_ICPSC_DIV1; TIM_ICInitStructure.TIM_ICFilter = 0x0; TIM_PWMIConfig(ADVANCE_TIM, &TIM_ICInitStructure); /* 选择定时器输入触发: TI1FP1 */ TIM_SelectInputTrigger(ADVANCE_TIM, TIM_TS_TI1FP1); /* 选择从模式: 复位模式 */ TIM_SelectSlaveMode(ADVANCE_TIM, TIM_SlaveMode_Reset); TIM_SelectMasterSlaveMode(ADVANCE_TIM,TIM_MasterSlaveMode_Enable); /* 使能高级控制定时器 */ TIM_Cmd(ADVANCE_TIM, ENABLE); /* 使能捕获/比较2中断请求 */ TIM_ITConfig(ADVANCE_TIM, TIM_IT_CC1, ENABLE); } /** * @brief 初始化高级控制定时器定时，1ms产生一次中断 * @param 无 * @retval 无 */ void TIM8_Configuration(void) { TIMx_GPIO_Config(); TIMx_NVIC_Configuration(); TIM_PWMOUTPUT_Config(); TIM_PWMINPUT_Config(); printf("TIMx_Configuration_ok\n"); } void ADVANCE_TIM_IRQHandler (void) { TIM_ClearITPendingBit(ADVANCE_TIM, TIM_IT_CC1); IC1Value = TIM_GetCapture1(ADVANCE_TIM); IC2Value = TIM_GetCapture2(ADVANCE_TIM); //printf("IC1Value = %d IC2Value = %d ",IC1Value,IC2Value); // LCD_ShowNum(0,60,IC1Value,8,16); // LCD_ShowNum(70,70,IC1Value,8,16); if (IC1Value != 0) { DutyCycle = (float)(IC2Value * 100) / IC1Value; Frequency = 168000000/168/(float)IC1Value; printf("占空比：%0.2f%% 频率：%0.2fHz\n",DutyCycle,Frequency); LCD_ShowNum(10,20,DutyCycle,8,16); LCD_ShowNum(60,40,Frequency,8,16); } else { DutyCycle = 0; Frequency = 0; } } // An highlighted block void PWM1_Intput_Mode_Config(void); /* 通用定时器PWM输出 */ /* PWM输出引脚 */ #define GENERAL_OCPWM_PIN GPIO_Pin_5 #define GENERAL_OCPWM_GPIO_PORT GPIOA #define GENERAL_OCPWM_GPIO_CLK RCC_AHB1Periph_GPIOA #define GENERAL_OCPWM_PINSOURCE GPIO_PinSource5 #define GENERAL_OCPWM_AF GPIO_AF_TIM2 /* 通用定时器 */ #define GENERAL_TIM TIM2 #define GENERAL_TIM_CLK RCC_APB1Periph_TIM2 /* 高级控制定时器PWM输入捕获 */ /* PWM输入捕获引脚 */ #define ADVANCE_ICPWM_PIN GPIO_Pin_6 #define ADVANCE_ICPWM_GPIO_PORT GPIOC #define ADVANCE_ICPWM_GPIO_CLK RCC_AHB1Periph_GPIOC #define ADVANCE_ICPWM_PINSOURCE GPIO_PinSource6 #define ADVANCE_ICPWM_AF GPIO_AF_TIM8 #define ADVANCE_IC1PWM_CHANNEL TIM_Channel_1 #define ADVANCE_IC2PWM_CHANNEL TIM_Channel_2 /* 高级控制定时器 */ #define ADVANCE_TIM TIM8 #define ADVANCE_TIM_CLK RCC_APB2Periph_TIM8 /* 捕获/比较中断 */ #define ADVANCE_TIM_IRQn TIM8_CC_IRQn #define ADVANCE_TIM_IRQHandler TIM8_CC_IRQHandler 外部计数器模式（高频）

原本我还不知道有这种用法，后来看到有人这样用，真的能测到很高100khz-15Mhz误差0.01%——0.02%，频率过于大存在一定的误差，总体还不错。外部计数器可以用于脉冲数计数下面展示一些内联代码片。

// A code block void TIM2_Cnt_Init(void) { GPIO_InitTypeDef GPIO_InitStructure; TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure; NVIC_InitTypeDef NVIC_InitStructure; TIM_DeInit(TIM2); TIM_DeInit(TIM7); RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2|RCC_APB1Periph_TIM7,ENABLE); RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOB, ENABLE); GPIO_InitStructure.GPIO_Pin = GPIO_Pin_3; //GPIOA0 GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF; GPIO_InitStructure.GPIO_Speed = GPIO_Speed_25MHz; GPIO_InitStructure.GPIO_OType = GPIO_OType_PP; GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL; GPIO_Init(GPIOB,&GPIO_InitStructure); //初始化PA0 GPIO_PinAFConfig(GPIOB,GPIO_PinSource3,GPIO_AF_TIM2); TIM_TimeBaseStructure.TIM_Prescaler=0; TIM_TimeBaseStructure.TIM_CounterMode=TIM_CounterMode_Up; TIM_TimeBaseStructure.TIM_Period=0xFFFFFFFF; TIM_TimeBaseStructure.TIM_ClockDivision=TIM_CKD_DIV1; TIM_TimeBaseInit(TIM2,&TIM_TimeBaseStructure); TIM_TIxExternalClockConfig(TIM2,TIM_TIxExternalCLK1Source_TI2,TIM_ICPolarity_Rising,0); TIM_TimeBaseStructure.TIM_Prescaler=18000-1; TIM_TimeBaseStructure.TIM_CounterMode=TIM_CounterMode_Up; TIM_TimeBaseStructure.TIM_Period=1000-1; TIM_TimeBaseStructure.TIM_ClockDivision=TIM_CKD_DIV1; NVIC_InitStructure.NVIC_IRQChannel = TIM7_IRQn; NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority=0; NVIC_InitStructure.NVIC_IRQChannelSubPriority =0; NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; NVIC_Init(&NVIC_InitStructure); TIM_ITConfig(TIM7,TIM_IT_Update,ENABLE); TIM_Cmd(TIM7,ENABLE ); TIM_Cmd(TIM2,ENABLE ); } u32 TIM7_LastCnt; u32 TIM_ExtCntFreq; //频率为TIM_ExtCntFreq void TIM7_IRQHandler(void) { char str[32]; TIM_ExtCntFreq=(TIM2->CNT-TIM7_LastCnt)*(1/0.1); // printf("%3.3f\n",TIM_ExtCntFreq/1.0/2.128); TIM7_LastCnt=TIM2->CNT; TIM_ClearITPendingBit(TIM7,TIM_IT_Update); }

借鉴了一些别人的做法，从中学到了经验，非常感谢__,把自己的学习过程记录一下，也是一个巩固的好方法。如果有错误，请大家指正

【本文地址】

公司简介

联系我们