F28335外部中断如何将下降沿触发变为上升沿

void InitExInt(void){
EALLOW;
GpioCtrlRegs.GPAMUX1.bit.GPIO13 = 0;
GpioCtrlRegs.GPADIR.bit.GPIO13 = 0;
GpioCtrlRegs.GPAQSEL1.bit.GPIO13= 0;
GpioIntRegs.GPIOXINT1SEL.bit.GPIOSEL = 13;//选择GPIO13为外部输入XINT3输入引脚
XIntruptRegs.XINT1CR.bit.POLARITY= 0;//下降沿触发中断
XIntruptRegs.XINT1CR.bit.ENABLE = 1; //使能XINT3中断
EDIS;