时钟由IO输出的方法，实现定时器触发IO翻转

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

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

 * [url=home.php?mod=space&uid=895143]@version[/url]  V1.00

 * [url=home.php?mod=space&uid=247401]@brief[/url]    Demonstrate the timer 0 toggle out function on TM0 pin.

 *

 * SPDX-License-Identifier: Apache-2.0

 * [url=home.php?mod=space&uid=17282]@CopyRight[/url] (C) 2020 Nuvoton Technology Corp. All rights reserved.

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

#include <stdio.h>

#include "NuMicro.h"





void SYS_Init(void)

{

    /* Unlock protected registers */

    SYS_UnlockReg();



    /* Enable HIRC */

    CLK_EnableXtalRC(CLK_PWRCTL_HIRCEN_Msk);



    /* Waiting for HIRC clock ready */

    CLK_WaitClockReady(CLK_STATUS_HIRCSTB_Msk);



    /* Switch HCLK clock source to HIRC */

    CLK_SetHCLK(CLK_CLKSEL0_HCLKSEL_HIRC, CLK_CLKDIV0_HCLK(1));



    /* Set both PCLK0 and PCLK1 as HCLK/2 */

    CLK->PCLKDIV = (CLK_PCLKDIV_APB0DIV_DIV2 | CLK_PCLKDIV_APB1DIV_DIV2);



    /* Switch UART0 clock source to HIRC */

    CLK_SetModuleClock(UART0_MODULE, CLK_CLKSEL1_UART0SEL_HIRC, CLK_CLKDIV0_UART0(1));



    /* Enable UART peripheral clock */

    CLK_EnableModuleClock(UART0_MODULE);



    /* Enable IP clock */

    CLK_EnableModuleClock(TMR0_MODULE);



    /* Select IP clock source */

    CLK_SetModuleClock(TMR0_MODULE, CLK_CLKSEL1_TMR0SEL_PCLK0, 0);



    /* Update System Core Clock */

    /* User can use SystemCoreClockUpdate() to calculate PllClock, SystemCoreClock and CycylesPerUs automatically. */

    SystemCoreClockUpdate();



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

    /* Init I/O Multi-function                                              */

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

    /* Set GPB multi-function pins for UART0 RXD and TXD */

    SYS->GPB_MFPH = (SYS->GPB_MFPH & ~(SYS_GPB_MFPH_PB12MFP_Msk | SYS_GPB_MFPH_PB13MFP_Msk)) |

                    (SYS_GPB_MFPH_PB12MFP_UART0_RXD | SYS_GPB_MFPH_PB13MFP_UART0_TXD);



    /* Set timer toggle out pin */

    SYS->GPB_MFPL = (SYS->GPB_MFPL & ~(SYS_GPB_MFPL_PB5MFP_Msk)) |

                    (SYS_GPB_MFPL_PB5MFP_TM0);



    /* Lock protected registers */

    SYS_LockReg();

}



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

/* Init UART0                                                           */

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

void UART0_Init(void)

{

    /* Reset UART0 */

    SYS_ResetModule(UART0_RST);



    /* Configure UART0 and set UART0 baud rate */

    UART_Open(UART0, 115200);

}



int main(void)

{

    /* Init System, IP clock and multi-function I/O. */

    SYS_Init();



    /* Init UART0 for printf */

    UART0_Init();



    printf("\nThis sample code use timer 0 to generate 500Hz toggle output to PB.5\n");



    /* To generate 500HZ toggle output, timer frequency must set to 1000Hz.

       Because toggle output state change on every timer timeout event */

    TIMER_Open(TIMER0, TIMER_TOGGLE_MODE, 1000);

    TIMER_SELECT_TOUT_PIN(TIMER0, TIMER_TOUT_PIN_FROM_TMX);

    TIMER_Start(TIMER0);



    while(1);

}