int Timer_FreeCountingMode(void)
{
    int volatile i;

    /* Init System, IP clock and multi-function I/O
       In the end of SYS_Init() will issue SYS_LockReg()
       to lock protected register. If user want to write
       protected register, please issue SYS_UnlockReg()
       to unlock protected register if necessary */
    SysInit();

    /* Init UART to 115200-8n1 for print message */
    UART_Open(UART0, 115200);

    printf("\nThis sample code demonstrate timer free counting mode.\n");
    printf("Please connect input source with Timer 0 capture pin PD.11, press any key to continue\n");
    UART_GeyChar();

    // Give a dummy target frequency here. Will over write capture resolution with macro
    TIMER_Open(TIMER0, TIMER_PERIODIC_MODE, 1000000);

    // Update prescale to set proper resolution.
    // Timer 0 clock source is 12MHz, to set resolution to 1us, we need to
    // set clock divider to 12. e.g. set prescale to 12 - 1 = 11
    TIMER_SET_PRESCALE_VALUE(TIMER0, 11);

    // Set compare value as large as possible, so don't need to worry about counter overrun too frequently.
    TIMER_SET_CMP_VALUE(TIMER0, 0xFFFFFF);

    // Configure Timer 0 free counting mode, capture TDR value on rising edge
    TIMER_EnableCapture(TIMER0, TIMER_CAPTURE_FREE_COUNTING_MODE, TIMER_CAPTURE_RISING_EDGE);

    // Start Timer 0
    TIMER_Start(TIMER0);

    // Enable timer interrupt
    TIMER_EnableCaptureInt(TIMER0);
    NVIC_EnableIRQ(TMR0_IRQn);

    while(1);

}
Exemple #2
0
/*---------------------------------------------------------------------------------------------------------*/
int main(void)
{
    volatile uint32_t u32InitCount;
    uint32_t au32CAPValus[10];

    /* Unlock protected registers */
    SYS_UnlockReg();

    /* Init System, peripheral clock and multi-function I/O */
    SYS_Init();

    /* Lock protected registers */
    SYS_LockReg();

    /* Init UART0 for printf */
    UART0_Init();

    printf("\n\nCPU @ %d Hz\n", SystemCoreClock);
    printf("+---------------------------------------------------+\n");
    printf("|    Timer External Capture Function Sample Code    |\n");
    printf("+---------------------------------------------------+\n\n");

    printf("# Timer Settings:\n");
    printf("  Timer0: Clock source is 12 MHz; Toggle-output mode and frequency is 500 Hz.\n");
    printf("  Timer3: Clock source is 12 MHz; Toggle-output mode and frequency is 1 Hz.\n");
    printf("  Timer2: Clock source is HCLK(72 MHz); Continuous counting mode; TCMP is 0xFFFFFF;\n");
    printf("          Counter pin enable; Capture pin and capture interrupt enable;\n");
    printf("# Generate 500 Hz frequency from TM0 and connect TM0 pin to Timer2 counter pin.\n");
    printf("# Generate 1 Hz frequency from TM3 and connect TM3 pin to TM2_EXT capture pin.\n");
    printf("# Get 500 event counts from Timer2 counter pin when each TM2_EXT pin interrupt occurred.\n\n");

    /* Initial Timer0 and Timer3 default setting */
    TIMER_Open(TIMER0, TIMER_TOGGLE_MODE, 1000);
    TIMER_Open(TIMER3, TIMER_TOGGLE_MODE, 2);

    /* Initial Timer2 default setting */
    TIMER_Open(TIMER2, TIMER_CONTINUOUS_MODE, 1);

    /* Configure Timer2 setting for external counter input and capture function */
    TIMER_SET_PRESCALE_VALUE(TIMER2, 0);
    TIMER_SET_CMP_VALUE(TIMER2, 0xFFFFFF);
    TIMER_EnableEventCounter(TIMER2, TIMER_COUNTER_FALLING_EDGE);
    TIMER_EnableCapture(TIMER2, TIMER_CAPTURE_FREE_COUNTING_MODE, TIMER_CAPTURE_FALLING_EDGE);
    TIMER_EnableCaptureInt(TIMER2);

    /* Enable Timer2 NVIC */
    NVIC_EnableIRQ(TMR2_IRQn);

    /* Clear Timer2 interrupt counts to 0 */
    u32InitCount = g_au32TMRINTCount[2] = 0;

    /* Start Timer0, Timer2 and Timer3 counting */
    TIMER_Start(TIMER0);
    TIMER_Start(TIMER2);
    TIMER_Start(TIMER3);

    /* Check TM2_EXT interrupt counts */
    while(1) {
        if(g_au32TMRINTCount[2] != u32InitCount) {
            au32CAPValus[u32InitCount] = TIMER_GetCaptureData(TIMER2);
            printf("[%2d] - %4d\n", g_au32TMRINTCount[2], au32CAPValus[u32InitCount]);
            if(u32InitCount > 1) {
                if((au32CAPValus[u32InitCount] - au32CAPValus[u32InitCount - 1]) != 500) {
                    printf("*** FAIL ***\n");
                    while(1);
                }
            }
            u32InitCount = g_au32TMRINTCount[2];
        }
        
        if(u32InitCount == 10)
            break;
    }

    /* Stop Timer0, Timer2 and Timer3 counting */
    TIMER_Close(TIMER0);
    TIMER_Close(TIMER2);
    TIMER_Close(TIMER3);

    printf("*** PASS ***\n");

    while(1);
}