[参考译文] TM4C1290NCPDT：尝试让脉冲计数器工作。

//****************************************************************************
//
// The variable g_ui32SysClock contains the system clock frequency in Hz.
//
//****************************************************************************
uint32_t g_ui32SysClock;


//*****************************************************************************
//
// The error routine that is called if the driver library encounters an error.
//
//*****************************************************************************
#ifdef DEBUG
void
__error__(char *pcFilename, uint32_t ui32Line)
{
}
#endif

//*****************************************************************************
//
// The interrupt handler for the Timer 0A interrupt.
//
//*****************************************************************************
void
Timer0AIntHandler(void)
{
    //
    // Clear the timer interrupt.
    //
    MAP_TimerIntClear(TIMER0_BASE, TIMER_CAPA_EVENT);

}

//*****************************************************************************
//
// The interrupt handler for the Timer 0B interrupt.
//
//*****************************************************************************
void
Timer0BIntHandler(void)
{
    //
    // Clear the timer interrupt.
    //
    MAP_TimerIntClear(TIMER0_BASE, TIMER_CAPB_EVENT);

}

//*****************************************************************************
//
// Configure the UART and its pins.  This must be called before UARTprintf().
//
//*****************************************************************************
void
ConfigureUART(void)
{
    //
    // Enable the GPIO Peripheral used by the UART.
    //
    MAP_SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOA);

    //
    // Enable UART0.
    //
    MAP_SysCtlPeripheralEnable(SYSCTL_PERIPH_UART0);

    //
    // Configure GPIO Pins for UART mode.
    //
    MAP_GPIOPinConfigure(GPIO_PA0_U0RX);
    MAP_GPIOPinConfigure(GPIO_PA1_U0TX);
    MAP_GPIOPinTypeUART(GPIO_PORTA_BASE, GPIO_PIN_0 | GPIO_PIN_1);

    //
    // Initialize the UART for console I/O.
    //
    UARTStdioConfig(0, 115200, g_ui32SysClock);
}

//*****************************************************************************
//
// Configure the system clock, UART, and setup Timer0 to be a Split Timer
// which uses the 8-bit prescaler to create two 24-bit timers to measure signal
// high periods based on rising and falling edge events on the Timer pins PL4
// and PL5.  The measurement results will be output on UART0 to the Virtual
// Serial Port.
//
//*****************************************************************************
int
main(void)
{
    uint32_t ui32EdgeCount = 0;
    uint32_t i;

    //
    // Run from the PLL at 120 MHz.
    // Note: SYSCTL_CFG_VCO_240 is a new setting provided in TivaWare 2.2.x and
    // later to better reflect the actual VCO speed due to SYSCTL#22.
    //
    g_ui32SysClock = MAP_SysCtlClockFreqSet((SYSCTL_XTAL_25MHZ |
                                             SYSCTL_OSC_MAIN |
                                             SYSCTL_USE_PLL |
                                             SYSCTL_CFG_VCO_240), 120000000);

    //
    // Enable the peripherals used by this example.
    //
    MAP_SysCtlPeripheralEnable(SYSCTL_PERIPH_TIMER0);
    MAP_SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOL);

    //
    // Configure the GPIO to be CCP pins for the Timer peripheral.
    //
    MAP_GPIOPinConfigure(GPIO_PL5_T0CCP1);

    //
    // Configure the GPIO for the Timer peripheral.
    //
    MAP_GPIOPinTypeTimer(GPIO_PORTL_BASE, GPIO_PIN_5);

    //
    // Initialize the UART and write initial status.
    //
    ConfigureUART();
    UARTprintf("Edge Capture Example for measuring the high period of an"
               "input signal.\n");
    UARTprintf("Input a square wave onto pin PL4 and PL5 of the "
               "EK-TM4C1294XL.\n");

    //
    // Initialize Timers A and B to both run as periodic up-count edge capture
    // timers.  This will split the 32-bit timer into two 16-bit timers.
    //
    MAP_TimerConfigure(TIMER0_BASE, (TIMER_CFG_SPLIT_PAIR |
                                     TIMER_CFG_B_PERIODIC |
				                     TIMER_CFG_B_CAP_COUNT_UP));

    //
    // To use the timer in Edge Time mode, it must be preloaded with initial
    // values.  If the prescaler is used, then it must be preloaded as well.
    // Since we want to use all 24-bits for both timers it will be loaded with
    // the maximum of 0xFFFF for the 16-bit wide split timers, and 0xFF to add
    // the additional 8-bits to the split timers with the prescaler.
    //
    MAP_TimerLoadSet(TIMER0_BASE, TIMER_BOTH, 0xFFFF);
    MAP_TimerPrescaleSet(TIMER0_BASE, TIMER_BOTH, 0xFF);

    //
    // configure Timer B
    // to trigger on a Negative Edge.
    //
    MAP_TimerControlEvent(TIMER0_BASE, TIMER_B, TIMER_EVENT_NEG_EDGE);

    //
    // Enable the Timer B interrupts for Capture Events.
    //
    MAP_TimerIntEnable(TIMER0_BASE, TIMER_CAPB_EVENT);


    //
    // Enable processor interrupts.
    //
    MAP_IntMasterEnable();

    //
    // Enable and wait for the port to be ready for access
    //
    SysCtlPeripheralEnable(SYSCTL_PERIPH_GPION);
    while(!SysCtlPeripheralReady(SYSCTL_PERIPH_GPION))
    {
    }

    //
    // Configure the GPIO port for the LED operation.
    //
    GPIOPinTypeGPIOOutput(GPIO_PORTN_BASE, GPIO_PIN_0);

    //
    // Enable both Timer Timer B to begin the application.
    //
    MAP_TimerEnable(TIMER0_BASE, TIMER_B);

    //
    // Loop Forever
    //
    for (i=0;i<100;i++)
    {
        //
        // Turn on the LED
        //
        GPIOPinWrite(GPIO_PORTN_BASE, GPIO_PIN_0, GPIO_PIN_0);

        //
        // Turn on the LED
        //
        GPIOPinWrite(GPIO_PORTN_BASE, GPIO_PIN_0, 0);

    }


    ui32EdgeCount = TimerValueGet(TIMER0_BASE, TIMER_B);

    if (ui32EdgeCount == 100){
        UARTprintf("pass");
    } else {
        UARTprintf("Fail");
    }

    while (1);


}