请问FX3/CX3定时器中断怎么实现？

我想实现一个中断定时器，请问怎么实现？
我之前从资料上看到说，可以通过GPIO中断实现，但是并没能产生中断，下面是我的代码：
// 初始化代码：
CyU3PGpioClock_t gpioClock;
CyU3PGpioComplexConfig_t gpioConfig;
CyU3PReturnStatus_t apiRetStatus = CY_U3P_SUCCESS;


/* Init the GPIO module */
gpioClock.fastClkDiv = 2;
gpioClock.slowClkDiv = 0;
gpioClock.simpleDiv = CY_U3P_GPIO_SIMPLE_DIV_BY_2;
gpioClock.clkSrc = CY_U3P_SYS_CLK;
gpioClock.halfDiv = 0;
apiRetStatus = CyU3PGpioInit( gpioClock, CyFxGpioIntrCb);

CyU3PGpioComplexConfig_t gpioComplexConfig;
gpioComplexConfig.outValue = CyFalse;
gpioComplexConfig.inputEn = CyTrue;
gpioComplexConfig.driveLowEn = CyFalse;
gpioComplexConfig.driveHighEn = CyFalse;
gpioComplexConfig.pinMode = CY_U3P_GPIO_MODE_STAtiC;
gpioComplexConfig.intrMode = CY_U3P_GPIO_INTR_TIMER_THRES;
gpioComplexConfig.timerMode = CY_U3P_GPIO_TIMER_POS_EDGE;
gpioComplexConfig.timer = 0;
gpioComplexConfig.period =  0x00000001;   // Reset after each interrupt
gpioComplexConfig.threshold = 0x00000001; //Generate interrupt every 125us


apiRetStatus = CyU3PGpioSetComplexConfig(GPIO_TIMER,  gpioComplexConfig);
if (apiRetStatus != CY_U3P_SUCCESS)
{
vJackyTestPrintErr("CyU3PGpioSetComplexConfig failed: %dn",apiRetStatus);
}

/*****************************************************/
// 中断回调函数：
/****************************************************/
void CyFxGpioIntrCb (
uint8_t gpioId /* Indicates the pin that triggered the interrupt */
)
{
if(GPIO_TIMER == gpioId)
{
dwTimeCountNow++;
if(dwTimeCountNow>TIME_COUNT_MAX)
{
dwTimeCountNow = 0;
}
}
}
/*******************************************/
// 请问如何才能产生timer 中断？如果GPIO可以做timer 中断，我的代码是否有问题啊？
// 非常期待老师的回答