/**************************************************************************//**
 * @file     main.c
 * @version  V3.00
 * $Revision: 2 $
 * $Date: 16/10/25 4:28p $
 * @brief    Implement WDT time-out interrupt event to wake up system and generate time-out reset system event while WDT time-out reset delay period expired.
 *
 * @note
 * @copyright SPDX-License-Identifier: Apache-2.0
 * @copyright Copyright (C) 2016 Nuvoton Technology Corp. All rights reserved.
 ******************************************************************************/
#include <stdio.h>
#include "NUC126.h"


#define PLLCTL_SETTING  CLK_PLLCTL_72MHz_HXT
#define PLL_CLOCK       72000000


/*---------------------------------------------------------------------------------------------------------*/
/* Global Interface Variables Declarations                                                                 */
/*---------------------------------------------------------------------------------------------------------*/
extern int IsDebugFifoEmpty(void);
volatile uint32_t g_u32WDTINTCounts;
volatile uint8_t g_u8IsWDTWakeupINT;


/*---------------------------------------------------------------------------------------------------------*/
/*  Function for System Entry to Power Down Mode                                                           */
/*---------------------------------------------------------------------------------------------------------*/
void PowerDownFunction(void)
{
    uint32_t u32TimeOutCnt;

    printf("\nSystem enter to power-down mode ...\n\n");

    /* To check if all the debug messages are finished */
    u32TimeOutCnt = SystemCoreClock; /* 1 second time-out */
    while(IsDebugFifoEmpty() == 0)
        if(--u32TimeOutCnt == 0) break;

    SCB->SCR = 4;

    /* To program PWRCTL register, it needs to disable register protection first. */
    CLK->PWRCTL &= ~(CLK_PWRCTL_PDEN_Msk);
    CLK->PWRCTL |= (CLK_PWRCTL_PDEN_Msk | CLK_PWRCTL_PDWKIEN_Msk);

    __WFI();
}

/**
 * @brief       IRQ Handler for WDT Interrupt
 *
 * @param       None
 *
 * @return      None
 *
 * @details     The WDT_IRQHandler is default IRQ of WDT, declared in startup_NUC126.s.
 */
void WDT_IRQHandler(void)
{
    if(g_u32WDTINTCounts < 10)
        WDT_RESET_COUNTER();

    if(WDT_GET_TIMEOUT_INT_FLAG() == 1)
    {
        /* Clear WDT time-out interrupt flag */
        WDT_CLEAR_TIMEOUT_INT_FLAG();

        g_u32WDTINTCounts++;
    }

    if(WDT_GET_TIMEOUT_WAKEUP_FLAG() == 1)
    {
        /* Clear WDT time-out wake-up flag */
        WDT_CLEAR_TIMEOUT_WAKEUP_FLAG();

        g_u8IsWDTWakeupINT = 1;
    }
}

void SYS_Init(void)
{
    /*---------------------------------------------------------------------------------------------------------*/
    /* Init System Clock                                                                                       */
    /*---------------------------------------------------------------------------------------------------------*/
    /* Enable HIRC clock */
    CLK->PWRCTL |= CLK_PWRCTL_HIRCEN_Msk;

    /* Waiting for HIRC clock ready */
    while(!(CLK->STATUS & CLK_STATUS_HIRCSTB_Msk));

    /* Switch HCLK clock source to HIRC */
    CLK->CLKSEL0 = CLK_CLKSEL0_HCLKSEL_HIRC;

    /* Set PLL to Power-down mode and PLLSTB bit in CLK_STATUS register will be cleared by hardware.*/
    CLK->PLLCTL |= CLK_PLLCTL_PD_Msk;

    /* Enable HXT and LIRC */
    CLK->PWRCTL |= CLK_PWRCTL_HXTEN_Msk | CLK_PWRCTL_LIRCEN_Msk;

    /* Enable PLL and Set PLL frequency */
    CLK->PLLCTL = PLLCTL_SETTING;

    /* Waiting for clock ready */
    while(!(CLK->STATUS & CLK_STATUS_PLLSTB_Msk));
    while(!(CLK->STATUS & CLK_STATUS_HXTSTB_Msk));
    while(!(CLK->STATUS & CLK_STATUS_LIRCSTB_Msk));

    /* Switch STCLK source to HCLK/2 and HCLK clock source to PLL */
    CLK->CLKSEL0 = CLK_CLKSEL0_STCLKSEL_HCLK_DIV2 | CLK_CLKSEL0_HCLKSEL_PLL;

    /* Enable peripheral clock */
    CLK->APBCLK0 = CLK_APBCLK0_UART0CKEN_Msk | CLK_APBCLK0_WDTCKEN_Msk;

    /* Peripheral clock source */
    CLK->CLKSEL1 = CLK_CLKSEL1_UARTSEL_PLL | CLK_CLKSEL1_WDTSEL_LIRC;

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

    /*---------------------------------------------------------------------------------------------------------*/
    /* Init I/O Multi-function                                                                                 */
    /*---------------------------------------------------------------------------------------------------------*/
    /* Set PD multi-function pins for UART0 RXD and TXD */
    SYS->GPD_MFPL &= ~(SYS_GPD_MFPL_PD0MFP_Msk | SYS_GPD_MFPL_PD1MFP_Msk);
    SYS->GPD_MFPL |= (SYS_GPD_MFPL_PD0MFP_UART0_RXD | SYS_GPD_MFPL_PD1MFP_UART0_TXD);
}

void UART0_Init(void)
{
    /*---------------------------------------------------------------------------------------------------------*/
    /* Init UART                                                                                               */
    /*---------------------------------------------------------------------------------------------------------*/
    /* Reset UART module */
    SYS->IPRST1 |=  SYS_IPRST1_UART0RST_Msk;
    SYS->IPRST1 &= ~SYS_IPRST1_UART0RST_Msk;

    /* Configure UART0 and set UART0 Baudrate */
    UART0->BAUD = UART_BAUD_MODE2 | UART_BAUD_MODE2_DIVIDER(PllClock, 115200);
    UART0->LINE = UART_WORD_LEN_8 | UART_PARITY_NONE | UART_STOP_BIT_1;
}

/*---------------------------------------------------------------------------------------------------------*/
/*  MAIN function                                                                                          */
/*---------------------------------------------------------------------------------------------------------*/
int main(void)
{
    uint32_t u32TimeOutCnt;

    /* 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("|    WDT Time-out Wake-up Sample Code    |\n");
    printf("+----------------------------------------+\n\n");

    /* To check if system has been reset by WDT time-out reset or not */
    if(WDT_GET_RESET_FLAG() == 1)
    {
        printf("*** System has been reset by WDT time-out reset event. [WDT_CTL: 0x%08X] ***\n\n", WDT->CTL);
        WDT_CLEAR_RESET_FLAG();
        while(1);
    }

    printf("# WDT Settings:\n");
    printf("    - Clock source is LIRC                  \n");
    printf("    - Time-out interval is 2^14 * WDT clock \n");
    printf("      (around 1.6384 ~ 1.7408 s)            \n");
    printf("    - Interrupt enable                      \n");
    printf("    - Wake-up function enable               \n");
    printf("    - Reset function enable                 \n");
    printf("    - Reset delay period is 18 * WDT clock  \n");
    printf("# System will generate a WDT time-out interrupt event after 1.6384 ~ 1.7408 s, \n");
    printf("    and will be wake up from power-down mode also.\n");
    printf("    (Use PA.0 high/low period time to check WDT time-out interval)\n");
    printf("# When WDT interrupt counts large than 10, \n");
    printf("    we will not reset WDT counter value and system will be reset immediately by WDT time-out reset signal.\n");

    /* Use PA.0 to check time-out period time */
    PA->MODE = 0xFFFFFFFD;
    PA0 = 1;

    /* Enable WDT NVIC */
    NVIC_EnableIRQ(WDT_IRQn);

    /* Because of all bits can be written in WDT Control Register are write-protected;
       To program it needs to disable register protection first. */
    SYS_UnlockReg();

    /* Configure WDT settings and start WDT counting */
    g_u32WDTINTCounts = g_u8IsWDTWakeupINT = 0;
    WDT->CTL = WDT_TIMEOUT_2POW14 | WDT_CTL_INTEN_Msk | WDT_CTL_WKEN_Msk | WDT_CTL_RSTEN_Msk | WDT_CTL_WDTEN_Msk;
    WDT->ALTCTL = WDT_RESET_DELAY_18CLK;

    while(1)
    {
        /* System enter to Power-down */
        /* To program PWRCTL register, it needs to disable register protection first. */
        SYS_UnlockReg();
        PowerDownFunction();

        /* Check if WDT time-out interrupt and wake-up occurred or not */
        u32TimeOutCnt = SystemCoreClock; /* 1 second time-out */
        while(g_u8IsWDTWakeupINT == 0)
        {
            if(--u32TimeOutCnt == 0)
            {
                printf("Wait for WDT interrupt time-out!\n");
                break;
            }
        }

        g_u8IsWDTWakeupINT = 0;
        PA0 ^= 1;

        printf("System has been waken up done. WDT interrupt counts: %d.\n\n", g_u32WDTINTCounts);
    }
}

/*** (C) COPYRIGHT 2016 Nuvoton Technology Corp. ***/
