STM32F103 读取传感器数据PWM

jiangxun · 发表于 2015-10-21 22:28:45

以下是PWM.c
#include "pwm.h"

void TIM3_PWM_Init(void)
{
GPIO_InitTypeDef GPIO_InitStructure;
TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;
TIM_OCInitTypeDef  TIM_OCInitStructure;
TIM_ICInitTypeDef  TIM_ICInitStructure;
RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE);
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA  | RCC_APB2Periph_AFIO, ENABLE);  //????GPIO???è??AFIO???????????é?±??????

  //?è??????????????????????,????TIM3 CH3==>

B0 CH4==>

B1 ??PWM?????¨??
GPIO_InitStructure.GPIO_Pin =GPIO_Pin_7; //??????GPIO
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;  //???????ì????
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(GPIOA, &GPIO_InitStructure);

TIM_ICInitStructure.TIM_Channel = TIM_Channel_2;                //?¨???è??
  TIM_ICInitStructure.TIM_ICPolarity = TIM_ICPolarity_Rising;    //????????·?
  TIM_ICInitStructure.TIM_ICSelection = TIM_ICSelection_DirectTI; //???????????÷????????
  TIM_ICInitStructure.TIM_ICPrescaler = TIM_ICPSC_DIV1;          //?????¤·??????????????????à????????????×???????????????????????±??????????????????á±??
  //±???????4·????ò????????????????×??????????????ù??????????±???????·±???é???????????????í??±?????????????????
  TIM_ICInitStructure.TIM_ICFilter = 0x0;                         //???¨?è???????ú??????????±????¨?¨?????¨0x0~0xf
  TIM_PWMIConfig(TIM3, &TIM_ICInitStructure);                      //?ù???????è??TIM???è????
  TIM_SelectInputTrigger(TIM3, TIM_TS_TI2FP2);                   //????IC2????????·???
  TIM_SelectSlaveMode(TIM3, TIM_SlaveMode_Reset);    //TIM??????????·??????????????????????????÷????·??????÷???ü??????
  TIM_SelectMasterSlaveMode(TIM3, TIM_MasterSlaveMode_Enable); //?????¨?±?÷??±?????·?
  TIM_Cmd(TIM3, ENABLE);                                           //????TIM3
  TIM_ITConfig(TIM3, TIM_IT_CC2, ENABLE);                         //?ò??????
}
u16 IC2Value = 0;
u16 DutyCycle = 0;
u16 Frequency = 0;
void TIM3_IRQHandler(void)
{
TIM_ClearITPendingBit(TIM3,TIM_IT_CC2);//????TIM???????????í??
IC2Value=TIM_GetCapture2(TIM3);  //????IC2?????????÷??????????PWM????????????
if(IC2Value!=0)
{
DutyCycle=(TIM_GetCapture1(TIM3)*100)/IC2Value;    //????IC1?????????÷????????????????±?
Frequency=72000000/IC2Value; //????PWM????
}
else
{
DutyCycle=0;
Frequency=0;
}
}

以下是main.c
#include "delay.h"
#include "sys.h"
#include "usart.h"
#include "exti.h"
#include "wdg.h"
#include "pwm.h"

extern void TIM3_IRQHandler(void);
extern void TIM3_PWM_Init(void);
extern u16 IC2Value;
extern u16 DutyCycle ;
extern u16 Frequency ;

int main(void)
{

SystemInit();
delay_init(72);          //???±??????
NVIC_Configuration();    //????????
uart_init(9600); //?®????????

while(1)
{
delay_ms(1004);
   if(!IC2Value)
{
printf("CO2    = %d\r\n",DutyCycle);
printf("CO2 = %d\r\n",Frequency);
}
}
}

为何读取不到数据呢？用的是PA7 TIM3_CH2