STM32F4定时器应用-等精度测频法

STM32F4定时器应用--等精度测频法

wfmjj 提问时间：2013-2-21 12:55 /

等精度测量法:定时器1对被测信号计数65536个周期作为闸门时间，在这个闸门时间内定时器2对标准信号进行计数。假定在这个闸门时间内标准信号的计数值为M。则有：65536/fc=M/fb通过这个公式就可以算出被测信号：fc=65536*fb/M。
本程序利用定时器3产生30KHZ的被测信号。定时器1对被测信号进行65536个周期计数。
定时器4产生60KHZ的标准信号。定时器2对标准信号在定时器1产生的闸门时间内计数。
主程序如下：
/**
  ******************************************************************************
  * @file app.c
  * @author  wangfei
  * @date 13-April-2012
  * @e-mail  wfmjj@hotmail.com
  * @brief Initialize peripherals.
  *****************************************************************************/
/* Includes ------------------------------------------------------------------*/
#include "stm32f4xx.h"
#include "app.h"
#include "bsp.h"
/* Private typedef -----------------------------------------------------------*/
/* Private define ------------------------------------------------------------*/
/* Private macro -------------------------------------------------------------*/
/* Private variables ---------------------------------------------------------*/
extern uint8_t TimeFlag;
extern uint32_t n_Counter;
uint16_t Counterh,Counterl;
uint8_t Data[5];
/* Private function prototypes -----------------------------------------------*/
/* Private functions ---------------------------------------------------------*//**
* @brief This function handles NMI exception.
  * @param  None
  * @retval None
  */
int main(void)
{
GPIO_ResetBits(GPIOE,(GPIO_Pin_0|GPIO_Pin_1|GPIO_Pin_2|GPIO_Pin_3));  //可以通过观察LED口高电平时间
Bsp_Init();
while(1)
{
uint8_t i;
TIM_ITConfig(TIM1,TIM_IT_Trigger,ENABLE);  //允许定时器1的触发中断
GPIO_SetBits(GPIOE,(GPIO_Pin_0|GPIO_Pin_1|GPIO_Pin_2|GPIO_Pin_3));
   TIM_Cmd(TIM1,ENABLE);                //打开定时器1,当检测到TIM1_CH1通道的上升沿后立即触发中断
while(TimeFlag==0);    //等待定时器1溢出中断
TIM1->DIER&=0X0000;    //失能定时器1的所有中断
GPIO_ResetBits(GPIOE,(GPIO_Pin_0|GPIO_Pin_1|GPIO_Pin_2|GPIO_Pin_3));  //可以通过观察LED口高电平时间
TimeFlag=0; //定时器1溢出标志置0
Counterh=n_Counter>>16;  //得到32位数据中的高16位
Counterl=n_Counter;    //得到32位数据中的低16位
Data[0]=Counterh>>8;
Data[1]=Counterh;
Data[2]=Counterl>>8;
Data[3]=Counterl;
  for(i=0;iCCMR1|=0X0100;  //配置定时器1为外部时钟模式1
TIM1->CCER&=0XFF5F;
TIM1->SMCR|=0X0067;
TIM_ClearFlag(TIM1,(TIM_FLAG_Update|TIM_FLAG_Trigger));
}
/**
  * @brief This function config timer3.
  * @param  None
  * @retval None
  */
void Bsp_TIM3_Config(void)
{
TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
TIM_OCInitTypeDef TIM_OCInitStructure;
RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE); //Open TIM3  Clock

TIM_TimeBaseStructure.TIM_Prescaler=3;       //clk_cnt prescale
TIM_TimeBaseStructure.TIM_CounterMode=TIM_CounterMode_Up; //TIM3 Count mode
TIM_TimeBaseStructure.TIM_Period=699;       //Fout_clk=Fclk_cnt/(ARR+1)=21000000/700=30KHZ
TIM_TimeBaseStructure.TIM_ClockDivision=0;

TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure);
/* PWM1 Mode configuration: TIM3_Ch1 */
TIM_OCInitStructure.TIM_OCMode=TIM_OCMode_PWM1;             //select PWM1 mode
TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable; //config oc1 as output
TIM_OCInitStructure.TIM_Pulse=350;                         //config TIM3_CCR1 vaule
TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High; //config oc1 high level avaliable
TIM_OC1Init(TIM3, &TIM_OCInitStructure);

TIM_OC1PreloadConfig(TIM3, TIM_OCPreload_Enable);       // turn on oc1 preload

/* PWM1 Mode configuration: TIM3_Ch2 */
TIM_OCInitStructure.TIM_OCMode=TIM_OCMode_PWM1;             //select PWM1 mode
TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable; //config oc2 as output
TIM_OCInitStructure.TIM_Pulse=200;                         //config TIM3_CCR2 vaule
TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High; //config oc2 high level avaliable
TIM_OC2Init(TIM3, &TIM_OCInitStructure);

TIM_OC2PreloadConfig(TIM3, TIM_OCPreload_Enable);       // turn on oc2 preload
/* PWM1 Mode configuration: TIM3_CH3 */
TIM_OCInitStructure.TIM_OCMode=TIM_OCMode_PWM1;             //select PWM1 mode
TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable; //config oc3 as output
TIM_OCInitStructure.TIM_Pulse=100;                         //config TIM3_CCR1 vaule
TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High; //config oc3 high level avaliable
TIM_OC3Init(TIM3, &TIM_OCInitStructure);

TIM_OC3PreloadConfig(TIM3, TIM_OCPreload_Enable);       // turn on oc3 preload

/* PWM1 Mode configuration: TIM3_CH4 */
TIM_OCInitStructure.TIM_OCMode=TIM_OCMode_PWM1;             //select PWM1 mode
TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable; //config oc4 as output
TIM_OCInitStructure.TIM_Pulse=500;                         //config TIM3_CCR1 vaule
TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High; //config oc4 high level avaliable
TIM_OC4Init(TIM3, &TIM_OCInitStructure);

TIM_OC4PreloadConfig(TIM3, TIM_OCPreload_Enable);       // turn on oc4 preload
TIM_ARRPreloadConfig(TIM3, ENABLE);  /* TIM3 enable counter */
  TIM_Cmd(TIM3, ENABLE);
}
/**
  * @brief This function config usart3.
  * @param  None
  * @retval None
  */
void Bsp_USART3_Config(void)
{
USART_InitTypeDef USART_InitStructure;

  RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART3,ENABLE); //turn on usart3 clock

  USART_InitStructure.USART_BaudRate =115200 ;       //波特率设置
  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;
  USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;
  USART_Init(USART3, &USART_InitStructure);

  //USART_ITConfig(USART3,USART_IT_RXNE,ENABLE);
  USART_Cmd(USART3,ENABLE);
  USART_ClearFlag(USART3, USART_FLAG_TC); //清除发送完成标志位
}
/**
  * @brief This function config nvic.
  * @param  None
  * @retval None
  */
void Bsp_NVIC_Config(void)
{
  NVIC_InitTypeDef NVIC_InitStructure;
NVIC_PriorityGroupConfig(NVIC_PriorityGroup_0);

  NVIC_InitStructure.NVIC_IRQChannel=TIM1_TRG_COM_TIM11_IRQn;
  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure);

  NVIC_InitStructure.NVIC_IRQChannel=TIM1_UP_TIM10_IRQn;
  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 2;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure);
}
/**
  * @brief This function config timer2.
  * @param  None
  * @retval None
  */
void Bsp_TIM2_Config(void)
{
TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;

RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2,ENABLE);  //打开定时器2的时钟
  TIM_DeInit(TIM2);

TIM_TimeBaseStructure.TIM_Prescaler=0;
  TIM_TimeBaseStructure.TIM_CounterMode=TIM_CounterMode_Up;    //定时器2向上计数
  TIM_TimeBaseStructure.TIM_Period=0xffff;
  TIM_TimeBaseStructure.TIM_ClockDivision = 0;
  TIM_TimeBaseInit(TIM2, &TIM_TimeBaseStructure);

TIM2->ARR|=0XFFFFFFFF; //配置
//定时器2外部时钟模式1的配置
TIM2->CCMR1|=0X0001;
TIM2->CCER&=0XFFF5;
TIM2->SMCR|=0X0057;

TIM_ClearFlag(TIM2,TIM_FLAG_Update); //初始化时必须将溢出中断清0必须在开溢出中断之前。
}
/**
  * @brief This function config timer4.
  * @param  None
  * @retval None
  */
void Bsp_TIM4_Config(void)
{
  TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
TIM_OCInitTypeDef TIM_OCInitStructure;

RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM4,ENABLE);  //turn on TIM4 clock TIM_TimeBaseStructure.TIM_Prescaler=1;       //Fck_cnt=84MHZ/2=42MHZ
TIM_TimeBaseStructure.TIM_CounterMode=TIM_CounterMode_Up; //TIM3 Count mode
TIM_TimeBaseStructure.TIM_Period=699;       //Fout_clk=Fclk_cnt/(ARR+1)=42000/700=60KHZ
TIM_TimeBaseStructure.TIM_ClockDivision=0;

TIM_TimeBaseInit(TIM4, &TIM_TimeBaseStructure);

/* PWM1 Mode configuration: TIM4_Ch1 */
TIM_OCInitStructure.TIM_OCMode=TIM_OCMode_PWM1;             //select PWM1 mode
TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable; //config oc1 as output
TIM_OCInitStructure.TIM_Pulse=350;                         //config TIM3_CCR1 vaule
TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High; //config oc1 high level avaliable
TIM_OC1Init(TIM4, &TIM_OCInitStructure);

TIM_OC1PreloadConfig(TIM4, TIM_OCPreload_Enable);       // turn on oc1 preload

/* PWM1 Mode configuration: TIM4_Ch2 */
TIM_OCInitStructure.TIM_OCMode=TIM_OCMode_PWM1;             //select PWM1 mode
TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable; //config oc2 as output
TIM_OCInitStructure.TIM_Pulse=500;                         //config TIM3_CCR2 vaule
TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High; //config oc2 high level avaliable
TIM_OC2Init(TIM4, &TIM_OCInitStructure);

TIM_OC2PreloadConfig(TIM4, TIM_OCPreload_Enable);       // turn on oc2 preload

/* PWM1 Mode configuration: TIM4_CH3 */
TIM_OCInitStructure.TIM_OCMode=TIM_OCMode_PWM1;             //select PWM1 mode
TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable; //config oc3 as output
TIM_OCInitStructure.TIM_Pulse=100;                         //config TIM3_CCR1 vaule
TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High; //config oc3 high level avaliable
TIM_OC3Init(TIM4, &TIM_OCInitStructure);

TIM_OC3PreloadConfig(TIM4, TIM_OCPreload_Enable);       // turn on oc3 preload
/* PWM1 Mode configuration: TIM4_CH4 */
TIM_OCInitStructure.TIM_OCMode=TIM_OCMode_PWM1;             //select PWM1 mode
TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable; //config oc4 as output
TIM_OCInitStructure.TIM_Pulse=600;                         //config TIM3_CCR1 vaule
TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High; //config oc4 high level avaliable
TIM_OC4Init(TIM4, &TIM_OCInitStructure);

TIM_OC4PreloadConfig(TIM4, TIM_OCPreload_Enable);       // turn on oc4 preload

TIM_ARRPreloadConfig(TIM4, ENABLE);  /* TIM3 enable counter */
  TIM_Cmd(TIM4, ENABLE);

}</em>

定时器1触发中断程序如下：
void TIM1_TRG_COM_TIM11_IRQHandler(void)
{
if(TIM_GetITStatus(TIM1,TIM_IT_Trigger)==SET)  //检查是否为触发中断
{
  TIM1->DIER&=0XFFBF; //清除定时器1的触发中断
  TIM1->DIER|=0X0001; //使能定时器1的溢出中断
  TIM2->CR1|=0X0001; //打开定时器2使其对标准信号开始计数
  TIM1->SR&=0XFFBF;    //在退出中断之前必须清除其中断标志位
}
}
定时器1溢出中断如下：
void TIM1_UP_TIM10_IRQHandler(void)
{
if(TIM_GetITStatus(TIM1,TIM_IT_Update)==SET)  //检查定时器1溢出标志位是否置1
{
  n_Counter=TIM2->CNT;  //读出计数器2的值
  TIM1->CR1&=0XFFFE; //关闭定时器1
  TIM2->CR1&=0XFFFE; //关闭定时器2
  TIM2->CNT&=0X0000; //清除计数器2计数寄存器的值
  TimeFlag=1;       //1s标志位置1
  TIM1->SR&=0XFFFE; //退出定时器1溢出中断之前,必须清除定时器1的溢出标志位
}
}