lm4f launchpad 在I2C中断初始化时代码越界

如题，在I2C初始化中断时，CCS仿真显示代码越界。一下是初始化代码：

SysCtlPeripheralEnable(SYSCTL_PERIPH_I2C0);
SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOB);

GPIOPinConfigure(GPIO_PB2_I2C0SCL);
GPIOPinConfigure(GPIO_PB3_I2C0SDA);
GPIOPinTypeI2C(GPIO_PORTB_BASE, GPIO_PIN_2 | GPIO_PIN_3);
HWREG(I2C0_MASTER_BASE + I2C_O_MCR) |= 0x01;

I2CMasterSlaveAddrSet(I2C0_MASTER_BASE, devAddr, false);
// 使能I2C中断 ;

IntEnable (INT_I2C0);
I2CMasterInitExpClk(I2C0_MASTER_BASE, SysCtlClockGet(), false);
I2CMasterEnable(I2C0_MASTER_BASE);
IntMasterEnable();

代码仿照例程所写，仿真到IntEnable (I2C0_MASTER_BASE);这句时卡住，CCS显示  Memory map prevented reading of target memory at 0xF000BE00 [code=0x20000]。求助