TM4C123GH6Pm测量一段高电平持续时间

LiKent

void Timer0IntHandler(void)
{


    TimerIntClear(TIMER0_BASE,TIMER_CAPA_EVENT);
    TimeLater=TimerValueGet(TIMER0_BASE,TIMER_A) ;

 

}

void InitTimer()
{
    SysCtlPeripheralEnable(SYSCTL_PERIPH_TIMER0); // Timer0

    SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOB);//PORTB for timer0

    GPIOPinConfigure(GPIO_PB6_T0CCP0 ); // configure PB6 for Timer0A
      GPIOPinTypeGPIOInput(GPIO_PORTB_BASE, GPIO_PIN_6);
     GPIOPinTypeTimer(GPIO_PORTB_BASE, GPIO_PIN_6);//PB6 for timer0
    TimerConfigure(TIMER0_BASE,TIMER_CFG_A_CAP_TIME_UP|TIMER_CFG_SPLIT_PAIR);
   TimerControlEvent(TIMER0_BASE,TIMER_A,TIMER_EVENT_BOTH_EDGES);

   if(GPIOPinRead(GPIO_PORTB_BASE, GPIO_PIN_6)==24)
     { 

         TimeBeginning=TimerValueGet(TIMER0_BASE,TIMER_A) ;

     }

  TimerLoadSet(TIMER0_BASE, TIMER_A, 1000);
     TimerIntRegister(TIMER0_BASE,TIMER_A,Timer0IntHandler);
    IntMasterEnable();
    TimerIntEnable(TIMER0_BASE, TIMER_CAPA_EVENT);
    TimerControlEvent(TIMER0_BASE,TIMER_A,TIMER_EVENT_NEG_EDGE);
    IntEnable(INT_TIMER0A);

   TimerEnable(TIMER0_BASE , TIMER_A);

    }

这样配置定时器：

使用Timer0 的PB6引脚作为方波输入引脚。

配置定时器向上计数。设置初值1000

定时器设置为上升沿触发，检测到上升沿时，获取定时器的值（使用TimeValueGet（）），作为方波高电平起点值。

中断注册为下降沿触发。中断函数里获取定时器的值，作为方波高电平终点值。两者作差得到高电平持续时间。

但是，我在运行程序时view expressions，发现只有高电平起点的定时器值一直为零。附图如下，这是为什么

8 年多前

0 LiKent 8 年多前

Prodigy 211 points

工程师大牛快进来看看啊

0 LiKent 8 年多前回复 LiKent

Prodigy 211 points

被定时器困扰了好久了

0 Maka Luo 8 年多前

TI__Genius 12740 points

if(GPIOPinRead(GPIO_PORTB_BASE, GPIO_PIN_6)==24)//24 0X18 PIN4 AND PIN5 
   { 
  
       TimeBeginning=TimerValueGet(TIMER0_BASE,TIMER_A) ; 
  
   }
这个函数永远进不去，TimeBeginning的值永远是初始化值。

0 LiKent 8 年多前回复 Maka Luo

Prodigy 211 points

#include <stdint.h>
#include <stdbool.h>
#include "inc/hw_memmap.h"
#include "inc/hw_types.h"
#include "inc/hw_ints.h"
#include "driverlib/interrupt.h"
#include "driverlib/sysctl.h"
#include "driverlib/uart.h"
#include "driverlib/gpio.h"
#include "driverlib/pin_map.h"
#include "driverlib/timer.h"
#include "driverlib/pwm.h"
#include "utils/uartstdio.h"

void Delay_Ns(uint32_t n)
 {
     uint32_t i = 0;
     for(i = n;i > 0;i--)
         SysCtlDelay(SysCtlClockGet() / 3);
 }

unsigned int TimeBeginning,TimeLater,interval;
int PF1;

void Timer0IntHandler(void)
{


    TimerIntClear(TIMER0_BASE,TIMER_CAPA_EVENT);
    TimeLater=TimerValueGet(TIMER0_BASE,TIMER_A) ;




}
 void InitUART()
 {
     SysCtlPeripheralEnable(SYSCTL_PERIPH_UART0);//Enable UART0 module

     SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOA);//for UART
     GPIOPinTypeUART(GPIO_PORTA_BASE, GPIO_PIN_0 | GPIO_PIN_1);//PA0&PA1 for UART0

     UARTClockSourceSet(UART0_BASE, UART_CLOCK_PIOSC);
   //configure the baud clock source the precision internal oscillator(UART_CLOCK_PIOSC)
     UARTStdioConfig(0, 4800, 16000000);

 }
void InitTimer()
{
    SysCtlPeripheralEnable(SYSCTL_PERIPH_TIMER0); // Timer0

    SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOB);//PORTB for timer0

    GPIOPinConfigure(GPIO_PB6_T0CCP0 ); // configure PB6 for Timer0A
 
   GPIOPinTypeGPIOInput(GPIO_PORTB_BASE, GPIO_PIN_6);
 
    GPIOPinTypeTimer(GPIO_PORTB_BASE, GPIO_PIN_6);//PB6 for timer0

   TimerConfigure(TIMER0_BASE,TIMER_CFG_A_CAP_TIME_UP|TIMER_CFG_SPLIT_PAIR);
  
  TimerControlEvent(TIMER0_BASE,TIMER_A,TIMER_EVENT_BOTH_EDGES);//both edge to start timing



  TimerLoadSet(TIMER0_BASE, TIMER_A, SysCtlClockGet()/1000);//16000
 
 

   TimerIntRegister(TIMER0_BASE,TIMER_A,Timer0IntHandler);
    IntMasterEnable();
    TimerIntEnable(TIMER0_BASE, TIMER_CAPA_EVENT);
    TimerControlEvent(TIMER0_BASE,TIMER_A,TIMER_EVENT_NEG_EDGE);
    IntEnable(INT_TIMER0A);

   TimerEnable(TIMER0_BASE , TIMER_A);
   if(GPIOPinRead(GPIO_PORTB_BASE, GPIO_PIN_6)==0x40)
        {
       UARTprintf("find pos edge");//to inspect whether this program ever entre  if{}
            TimeBeginning=TimerValueGet(TIMER0_BASE,TIMER_A) ;

        }

    }


void InitPWM()
{
        SysCtlPWMClockSet(SYSCTL_PWMDIV_1);
        SysCtlPeripheralEnable(SYSCTL_PERIPH_PWM1);//使能pwm1外设
        SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOF);//使能PF
        GPIOPinConfigure(GPIO_PF1_M1PWM5 );//设置端口复用，
        GPIOPinTypePWM(GPIO_PORTF_BASE, GPIO_PIN_1);//设置端口的pwm输出功能

        PWMGenConfigure(PWM1_BASE, PWM_GEN_2, PWM_GEN_MODE_DOWN | PWM_GEN_MODE_NO_SYNC);//下降计数，非同步
        PWMGenPeriodSet(PWM1_BASE, PWM_GEN_2, 640);//0.1MHz

        PWMPulseWidthSet(PWM1_BASE, PWM_OUT_5, 320);//占空比50%，脉冲宽度320
        PWMOutputState(PWM1_BASE, PWM_OUT_5_BIT, true);
        PWMGenEnable(PWM1_BASE, PWM_GEN_2);
        PF1=GPIOPinRead(GPIO_PORTF_BASE,GPIO_PIN_1);
        }
/*
 *PB6 for timer0
 * trigPWM PF1
 * echo PB6
 * UART0 PA0 & PA1
 * */
    int main(void)
   {
      uint32_t distance;
        SysCtlClockSet(SYSCTL_SYSDIV_1|SYSCTL_USE_OSC|SYSCTL_OSC_MAIN|SYSCTL_XTAL_16MHZ);

        InitPWM();
        InitUART();
        UARTprintf("Hello ,measurement starts->\n");







while(1)
{

            InitTimer();

       distance=0;

       interval=TimeLater-TimeBeginning;
        UARTprintf("The time is %d:\n",interval);
       distance=1.0/interval*17000;

        UARTprintf("The distance is %d\n:",distance);
        Delay_Ns(3);





}
 }

TimeBeginning还是0，没有发生任何变化。UART，PWM配置正确。求解问题到底出在哪里

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TM4C123GH6Pm测量一段高电平持续时间