/**************************************************************************//**
 * @file     main.c
 * @version  V1.00
 * @brief    Use timer to wake up system from Power-down mode periodically.
 *
 * SPDX-License-Identifier: Apache-2.0
 * @copyright (C) 2020 Nuvoton Technology Corp. All rights reserved.
 ****************************************************************************/
#include <stdio.h>
#include "NuMicro.h"


void TMR0_IRQHandler(void)
{
    /* Clear wake up flag */
    TIMER_ClearWakeupFlag(TIMER0);
    /* Clear interrupt flag */
    TIMER_ClearIntFlag(TIMER0);
}

void SYS_Init(void)
{
    /* Unlock protected registers */
    SYS_UnlockReg();

    /* Switch HCLK clock source to HIRC */
    CLK_SetHCLK(CLK_CLKSEL0_HCLKSEL_HIRC, CLK_CLKDIV0_HCLK(1));

    /* Enable LIRC */
    CLK_EnableXtalRC(CLK_PWRCTL_LIRCEN_Msk);

    /* Waiting for LIRC clock ready */
    CLK_WaitClockReady(CLK_STATUS_LIRCSTB_Msk);

    /* Set both PCLK0 and PCLK1 as HCLK/2 */
    CLK->PCLKDIV = (CLK_PCLKDIV_APB0DIV_DIV2 | CLK_PCLKDIV_APB1DIV_DIV2);

    /* Enable UART peripheral clock */
    CLK_EnableModuleClock(UART0_MODULE);

    /* Switch UART0 clock source to HIRC */
    CLK_SetModuleClock(UART0_MODULE, CLK_CLKSEL1_UART0SEL_HIRC, CLK_CLKDIV0_UART0(1));

    /* Select Timer clock source from LIRC */
    CLK_EnableModuleClock(TMR0_MODULE);
    CLK_SetModuleClock(TMR0_MODULE, CLK_CLKSEL1_TMR0SEL_LIRC, 0);

    /* Update System Core Clock */
    /* User can use SystemCoreClockUpdate() to calculate PllClock, SystemCoreClock and CycylesPerUs automatically. */
    SystemCoreClockUpdate();

    /*----------------------------------------------------------------------*/
    /* Init I/O Multi-function                                              */
    /*----------------------------------------------------------------------*/
    /* Set PB multi-function pins for UART0 RXD=PB.6 and TXD=PB.4 */
    SYS->GPB_MFP1 = (SYS->GPB_MFP1 & ~(SYS_GPB_MFP1_PB4MFP_Msk | SYS_GPB_MFP1_PB6MFP_Msk)) |
                    (SYS_GPB_MFP1_PB4MFP_UART0_TXD | SYS_GPB_MFP1_PB6MFP_UART0_RXD);

    /* Set PB multi-function pins for CLKO(PB.7) */
    SYS->GPB_MFP1 = (SYS->GPB_MFP1 & ~(SYS_GPB_MFP1_PB7MFP_Msk)) |
                    (SYS_GPB_MFP1_PB7MFP_CLKO);

    /* 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)
{
    int i = 0;

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

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

    printf("Timer power down/wake up sample code\n");
    while(!UART_IS_TX_EMPTY(UART0));

    /* Output selected clock to CKO, CKO Clock = HCLK / 1 */
    CLK_EnableCKO(CLK_CLKSEL1_CLKOSEL_HCLK, 0, 1);

    /* Initial Timer0 to periodic mode with 1Hz, since system is fast (48MHz)
       and timer is slow (32kHz), and following function calls all modified timer's
       CTL register, so add extra delay between each function call and make sure the
       setting take effect */
    TIMER_Open(TIMER0, TIMER_PERIODIC_MODE, 1);
    CLK_SysTickDelay(50);
    /* Enable timer wake up system */
    TIMER_EnableWakeup(TIMER0);
    CLK_SysTickDelay(50);
    /* Enable Timer0 interrupt */
    TIMER_EnableInt(TIMER0);
    CLK_SysTickDelay(50);
    NVIC_EnableIRQ(TMR0_IRQn);
    /* Start Timer0 counting */
    TIMER_Start(TIMER0);
    CLK_SysTickDelay(50);
    /* Unlock protected registers */
    SYS_UnlockReg();
    while(1)
    {
        printf("Enter Power-down !\n");
        while(!UART_IS_TX_EMPTY(UART0));
        CLK_PowerDown();
        printf("Wake %d\n", i++);
        while(!UART_IS_TX_EMPTY(UART0));
        CLK_SysTickDelay(1000000);
    }
}
