[DemoCode下载] 利用定时器捕捉双边沿

/**************************************************************************//**

 * [url=home.php?mod=space&uid=288409]@file[/url]    main.c

 * @brief

 *          Demonstrate how to use the TIMER0 capture function to capture

 *          both edge of external capture signal and calculate the time

 *          of high level duration of capture signal.

 * @note

 * Copyright (C) 2013 Nuvoton Technology Corp. All rights reserved.

 ******************************************************************************/

#include <stdio.h>

#include "M0518.h"



/****************************************************************************/

/* Define                                                                   */

/****************************************************************************/



#define HCLK_CLOCK           50000000



/****************************************************************************/

/* Global variables                                                         */

/****************************************************************************/



volatile uint32_t g_au32TMRCapCountRise, g_au32TMRCapCountFall, g_u32TimerCapFlag;



/****************************************************************************/

/* Functions                                                                */

/****************************************************************************/



/*------------------------------*/

/* TIMER0 interrupt handler     */

/*------------------------------*/

void TMR0_IRQHandler(void)

{

    if (TIMER_GetCaptureIntFlag(TIMER0) == 1)

    {

        /* Clear TIMER0 capture interrupt flag */

        TIMER_ClearCaptureIntFlag(TIMER0);



        if (PB15)

        {

            /* Save the capture counter for PB15 rising edge */

            g_au32TMRCapCountRise = TIMER_GetCaptureData(TIMER0);

        }

        else

        {

            /* Save the capture counter for PB15 falling edge */

            g_au32TMRCapCountFall = TIMER_GetCaptureData(TIMER0);

            g_u32TimerCapFlag = 1;

        }

    }

}



void SYS_Init(void)

{

    /*------------------------------*/

    /* Init System Clock            */

    /*------------------------------*/



    /* Enable HIRC clock */

    CLK_EnableXtalRC(CLK_PWRCON_IRC22M_EN_Msk);



    /* Waiting for HIRC clock ready */

    CLK_WaitClockReady(CLK_CLKSTATUS_IRC22M_STB_Msk);



    /* Switch HCLK clock source to HIRC */

    CLK_SetHCLK(CLK_CLKSEL0_HCLK_S_HIRC, CLK_CLKDIV_HCLK(1));



    /* Enable HXT */

    CLK_EnableXtalRC(CLK_PWRCON_XTL12M_EN_Msk);



    /* Waiting for clock ready */

    CLK_WaitClockReady(CLK_CLKSTATUS_XTL12M_STB_Msk);



    /* Set core clock as HCLK_CLOCK from PLL and SysTick source to HCLK/2*/

    CLK_SetCoreClock(HCLK_CLOCK);



    /* Enable peripheral clock */

    CLK_EnableModuleClock(UART0_MODULE);

    CLK_EnableModuleClock(TMR0_MODULE);



    /* Peripheral clock source */

    CLK_SetModuleClock(UART0_MODULE, CLK_CLKSEL1_UART_S_PLL, CLK_CLKDIV_UART(1));

    CLK_SetModuleClock(TMR0_MODULE, CLK_CLKSEL1_TMR0_S_HCLK, 0);



    /*------------------------------*/

    /* Init I/O Multi-function      */

    /*------------------------------*/

    /* Set PB multi-function pins for UART0 RXD, TXD */

    SYS->GPB_MFP = SYS_GPB_MFP_PB0_UART0_RXD | SYS_GPB_MFP_PB1_UART0_TXD;



    /* Set PB multi-function pins for TM0_EXT on PB.15 */

    SYS->GPB_MFP |= (SYS_GPB_MFP_PB15_TM0_EXT);

    SYS->ALT_MFP  = SYS_ALT_MFP_PB15_TM0_EXT;

}





void UART0_Init(void)

{

    /*------------------------------*/

    /* Init UART                    */

    /*------------------------------*/

    /* Reset UART IP */

    SYS_ResetModule(UART0_RST);



    /* Configure UART0 and set UART0 Baudrate */

    UART_Open(UART0, 115200);

}





/*------------------------------*/

/* Main Function                */

/*------------------------------*/

int main(void)

{

    uint32_t u32CAPValue = 0;

    uint32_t u32delayCounter;



    /* 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("CPU [url=home.php?mod=space&uid=72445]@[/url] %d Hz\n", SystemCoreClock);

    printf("+------------------------------------------+\n");

    printf("|    TIMER0 Capture Counter Sample Code    |\n");

    printf("+------------------------------------------+\n\n");

    printf(" * Please connect PB14 and PB15 by wire.\n");



    /* Config PB14 to GPIO output mode to generate a pulse as external capture signal */

    PB14 = 0;

    GPIO_SetMode(PB, BIT14, GPIO_PMD_OUTPUT);



    /*----- Initial TIMER0 -----*/



    SYS_ResetModule(TMR0_RST);

    TIMER_Open(TIMER0, TIMER_CONTINUOUS_MODE, 1);



    /* Configure TIMER0 setting for external counter input and capture function */

    /* Set TIMER0 clock to HCLK/(1+1) */

    TIMER_SET_PRESCALE_VALUE(TIMER0, 1);

    printf("TIMER0 clock @ %d Hz\n", SystemCoreClock / 2);

    /* Reset TIMER0 counter value */

    TIMER_SET_CMP_VALUE(TIMER0, 0xFFFFFF);

    /* Set TIMER0 to capture both edges */

    TIMER_EnableCapture(TIMER0, TIMER_CAPTURE_FREE_COUNTING_MODE, TIMER_CAPTURE_FALLING_AND_RISING_EDGE);

    /* Enable TIMER0 capture interrupt */

    TIMER_EnableCaptureInt(TIMER0);

    NVIC_EnableIRQ(TMR0_IRQn);



    /*---- Begin to test -----*/



    g_au32TMRCapCountRise = g_au32TMRCapCountFall = g_u32TimerCapFlag = 0;



    /* Start TIMER0 counting */

    TIMER_Start(TIMER0);



    /* Generate a pulse with both rising edge and falling edge to PB14 */

    PB14 = 1;   /* Rising edge */



    /* Delay to keep high level of pulse. */

    /* Change the delay counter will get different capture counter value */

    for (u32delayCounter = 0; u32delayCounter < 10000; u32delayCounter++);



    PB14 = 0;   /* Falling edge */



    /* Wait a rising edge and a falling edge from PB15 */

    /* TIMER0 interrupt handler will set g_u32TimerCapFlag to 1 when received */

    /*      external capture signal from PB15 */

    while (g_u32TimerCapFlag == 0);



    /* Got the counter value for external capture signal */

    if (g_au32TMRCapCountFall > g_au32TMRCapCountRise)

        u32CAPValue = g_au32TMRCapCountFall - g_au32TMRCapCountRise;

    else

        /* In the case that TIMER0 counter overflowed */

        u32CAPValue = 0xffffff - g_au32TMRCapCountRise + g_au32TMRCapCountFall;



    printf("Capture counter for rising edge: 0x%X (%d)\n", g_au32TMRCapCountRise, g_au32TMRCapCountRise);

    printf("Capture counter for falling edge: 0x%X (%d)\n", g_au32TMRCapCountFall, g_au32TMRCapCountFall);

    printf("\n");

    printf("Capture counter for high level duration: 0x%X (%d)\n", u32CAPValue, u32CAPValue);

    printf("The high level duration time should be about (TIMER0 clock) * %d\n", u32CAPValue);

    printf("                                             = %d us\n", u32CAPValue / (SystemCoreClock / 2 / 1000000));



    /* Stop TIMER0 counting */

    TIMER_Close(TIMER0);



    while (1);

}



/*** (C) COPYRIGHT 2013 Nuvoton Technology Corp. ***/