LM4F120XL定时器捕获问题

//*****************************************************************************
//
// pwm.c - Example demonstrating timer-based PWM on a 16-bit CCP.
//
// Copyright (c) 2010-2012 Texas Instruments Incorporated. All rights reserved.
// Software License Agreement
//
// Texas Instruments (TI) is supplying this software for use solely and
// exclusively on TI's microcontroller products. The software is owned by
// TI and/or its suppliers, and is protected under applicable copyright
// laws. You may not combine this software with "viral" open-source
// software in order to form a larger program.
//
// THIS SOFTWARE IS PROVIDED "AS IS" AND WITH ALL FAULTS.
// NO WARRANTIES, WHETHER EXPRESS, IMPLIED OR STATUTORY, INCLUDING, BUT
// NOT LIMITED TO, IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE APPLY TO THIS SOFTWARE. TI SHALL NOT, UNDER ANY
// CIRCUMSTANCES, BE LIABLE FOR SPECIAL, INCIDENTAL, OR CONSEQUENTIAL
// DAMAGES, FOR ANY REASON WHATSOEVER.
//
// This is part of revision 9453 of the Stellaris Firmware Development Package.
//
//*****************************************************************************

/*PB5（TIMER1_B）产生PWM并且是正常的，配置PB1（TIMER2_B）捕获产生pwm的下降沿，但是中断函数一直进不去啊，设置断点发现进不去，求助，问题出在哪里，*/（已经在startup_ccs.c中注册了中断函数）

#ifndef PART_LM4F120H5QR
#define PART_LM4F120H5QR
#endif

#include "inc/hw_memmap.h"
#include "inc/hw_types.h"
#include "inc/hw_timer.h"
#include "inc/hw_ints.h"
#include "inc/hw_gpio.h"
#include "driverlib/timer.h"
#include "driverlib/interrupt.h"
#include "driverlib/sysctl.h"
#include "driverlib/gpio.h"
#include "utils/uartstdio.h"
#include "driverlib/pin_map.h"

//*****************************************************************************
//
// Configure Timer1B as a 16-bit PWM with a duty cycle of 66%.
//
//*****************************************************************************

int i=0;
void Timer2BIntHandler(void);

int main(void)
{
//
// Set the clocking to run directly from the external crystal/oscillator.
//
SysCtlClockSet(SYSCTL_SYSDIV_4 | SYSCTL_USE_OSC | SYSCTL_OSC_MAIN |
SYSCTL_XTAL_16MHZ);

//
// The Timer1 peripheral must be enabled for use.
//
SysCtlPeripheralEnable(SYSCTL_PERIPH_TIMER1);
SysCtlPeripheralEnable(SYSCTL_PERIPH_TIMER2);
//
// For this example CCP1 is used with port B pin 5.
// The actual port and pins used may be different on your part, consult
// the data sheet for more information.
// GPIO port B needs to be enabled so these pins can be used.
//
SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOB);

//
// Configure the GPIO pin muxing for the Timer/CCP function.
// This is only necessary if your part supports GPIO pin function muxing.
// Study the data sheet to see which functions are allocated per pin.
//
GPIOPinConfigure(GPIO_PB5_T1CCP1);
GPIOPinConfigure(GPIO_PB1_T2CCP1);
//
// Set up the serial console to use for displaying messages. This is
// just for this example program and is not needed for Timer/PWM operation.
//
GPIOPinTypeTimer(GPIO_PORTB_BASE, GPIO_PIN_5);
GPIOPinTypeTimer(GPIO_PORTB_BASE, GPIO_PIN_1);

//
// Configure Timer1B as a 16-bit periodic timer.
//
TimerConfigure(TIMER1_BASE, TIMER_CFG_16_BIT_PAIR |
TIMER_CFG_B_PWM);
TimerConfigure(TIMER2_BASE, TIMER_CFG_16_BIT_PAIR |
TIMER_CFG_B_CAP_COUNT);
//
// Set the Timer1B load value to 50000. For this example a 66% duty
// cycle PWM signal will be generated. From the load value (i.e. 50000)
// down to match value (set below) the signal will be high. From the
// match value to 0 the timer will be low.
//
TimerLoadSet(TIMER1_BASE, TIMER_B, 40000);

TimerLoadSet(TIMER2_BASE, TIMER_B, 1);
TimerControlEvent(TIMER2_BASE,TIMER_B,TIMER_EVENT_NEG_EDGE);
//
// Set the Timer1B match value to load value / 3.
//
TimerMatchSet(TIMER1_BASE, TIMER_B, TimerLoadGet(TIMER1_BASE, TIMER_B) / 2);
TimerMatchSet(TIMER2_BASE, TIMER_B, 1);
//
// Enable Timer1B.
//
IntMasterEnable();

TimerEnable(TIMER1_BASE, TIMER_B);

TimerIntEnable(TIMER2_BASE, TIMER_CAPB_EVENT);
IntEnable(INT_TIMER2B);
TimerEnable(TIMER2_BASE, TIMER_B);

TimerIntRegister(TIMER2_BASE, TIMER_B,Timer2BIntHandler);
//
// Loop forever while the Timer1B PWM runs.
//
while(1)
{
;
}
}

void Timer2BIntHandler(void)
{
i++;
if(i==10000)
{
i=0;
}
}

PB5（TIMER1_B）产生PWM并且是正常的，配置PB1（TIMER2_B）捕获产生pwm的下降沿，但是中断函数一直进不去啊，设置断点发现进不去，求助，问题出在哪里，