STM32F3-PWM输入捕获测量频率脉宽…

利用STM32的PWM输入捕获功能，可以测方波的占空比和(或)频率

使用时将相应的输入配置为对应定时器对应的复用功能，外部待测量波形从该引脚输入

再配置定时器输入捕获功能相应参数，选择主从模式，最后打开中断或者DMA读取测量数据

1. Enable TIM clock 
2. Configure the TIM pins by configuring the corresponding
GPIO pins
3.  Fill the
TIM_ICInitStruct 
5. Call TIM_ICInit(TIMx, &TIM_ICInitStruct) ;. Call
TIM_PWMIConfig(TIMx, &TIM_ICInitStruct) ;
6. Enable the NVIC or the DMA to read the measured
frequency.
7. Enable the corresponding interrupt (or DMA request) to read
the Captured value
8. Configure the slave mode controller in reset mode
9. Call the TIM_Cmd(ENABLE) function to enable the TIM
counter.
10. Use TIM_GetCapturex(TIMx); to read the captured
value.

代码：

#ifndef
__PWM_INPUT_H
#define
__PWM_INPUT_H
#include "main.h"
#define PWM_INPUT_TIM
TIM3
#define PWM_INPUT_TIM_CLK
RCC_APB1Periph_TIM3
#define PWM_INPUT_CHANNEL
     
TIM_Channel_2
#define PWM_INPUT_PIN
GPIO_Pin_4
#define PWM_INPUT_PORT
GPIOA
#define PWM_INPUT_GPIOCLK
RCC_AHBPeriph_GPIOA
#define PWM_INPUT_GPIOAF
GPIO_AF_2
#define PWM_INPUT_PINSOURCE
    GPIO_PinSource4
void
PWM_INPUT_Config(void);
void
TIM3_IRQHandler(void);
#endif

//========================================================/
#include
"PWM_Input.h"
volatile  
uint16_t IC2Value = 0;
volatile uint16_t DutyCycle =
0;
volatile uint32_t Frequency =
0;
void
PWM_INPUT_Config(void)
{
GPIO_InitTypeDef
GPIO_InitStructure;
 
NVIC_InitTypeDef NVIC_InitStructure;
 
TIM_ICInitTypeDef
 TIM_ICInitStructure; 

RCC_AHBPeriphClockCmd(PWM_INPUT_GPIOCLK,ENABLE);
RCC_APB1PeriphClockCmd(PWM_INPUT_TIM_CLK,ENABLE);

 GPIO_InitStructure.GPIO_Pin
  = PWM_INPUT_PIN;
 GPIO_InitStructure.GPIO_Mode
 = GPIO_Mode_AF;
 GPIO_InitStructure.GPIO_Speed
= GPIO_Speed_50MHz;
 GPIO_InitStructure.GPIO_OType
= GPIO_OType_PP;
 GPIO_InitStructure.GPIO_PuPd
 = GPIO_PuPd_UP;
 GPIO_Init(PWM_INPUT_PORT,
&GPIO_InitStructure);
 GPIO_PinAFConfig(PWM_INPUT_PORT,
PWM_INPUT_PINSOURCE, PWM_INPUT_GPIOAF);

 
NVIC_InitStructure.NVIC_IRQChannel = TIM3_IRQn;
 NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority
= 0;
 NVIC_InitStructure.NVIC_IRQChannelCmd
= ENABLE;
 NVIC_Init(&NVIC_InitStructure);

 TIM_ICInitStructure.TIM_Channel=PWM_INPUT_CHANNEL;
 TIM_ICInitStructure.TIM_ICFilter=0x0;
 TIM_ICInitStructure.TIM_ICPolarity=TIM_ICPolarity_Rising;
 TIM_ICInitStructure.TIM_ICPrescaler=TIM_ICPSC_DIV1;
 TIM_ICInitStructure.TIM_ICSelection=TIM_ICSelection_DirectTI;
 TIM_PWMIConfig(PWM_INPUT_TIM,&TIM_ICInitStructure);
 TIM_SelectInputTrigger(PWM_INPUT_TIM,TIM_TS_TI2FP2);
 TIM_SelectSlaveMode(PWM_INPUT_TIM,TIM_SlaveMode_Reset);
 TIM_SelectMasterSlaveMode(PWM_INPUT_TIM,TIM_MasterSlaveMode_Enable);
 TIM_Cmd(PWM_INPUT_TIM,ENABLE);
 TIM_ITConfig(PWM_INPUT_TIM,TIM_IT_CC2,ENABLE);
}
void
TIM3_IRQHandler(void)
{
 TIM_ClearITPendingBit(TIM3,
TIM_IT_CC2);
 IC2Value =
TIM_GetCapture2(TIM3);
 if (IC2Value
!= 0)
 {
 
 DutyCycle = (TIM_GetCapture1(TIM3) * 100) /
IC2Value;
 
 Frequency = 72000000 / IC2Value;
 }
 else
 {
 
 DutyCycle = 0;
 
 Frequency = 0;
 }
// printf("DutyCycle=
%d\n",DutyCycle);
// printf("Frequency=
%d\n",Frequency);
}
风子
2015,05,23