/**************************************************************************//**
 * @file     main.c
 * @version  V3.00
 * $Revision: 6 $
 * $Date: 15/07/02 11:18a $
 * @brief
 *           Demonstrate how to cause WDT time-out reset system event while WDT time-out reset delay period expired.
 *
 * @note
 * Copyright (C) 2014~2015 Nuvoton Technology Corp. All rights reserved.
 ******************************************************************************/
#include <stdio.h>
#include "NUC123.h"

#define PLLCON_SETTING      CLK_PLLCON_72MHz_HXT
#define PLL_CLOCK           72000000


/*---------------------------------------------------------------------------------------------------------*/
/* Global Interface Variables Declarations                                                                 */
/*---------------------------------------------------------------------------------------------------------*/
extern int IsDebugFifoEmpty(void);
volatile uint8_t g_u8IsWDTTimeoutINT = 0;


/**
 * @brief       IRQ Handler for WDT and WWDT Interrupt
 *
 * @param       None
 *
 * @return      None
 *
 * @details     The WDT_IRQHandler is default IRQ of WDT and WWDT, declared in startup_NUC123.s.
 */
void WDT_IRQHandler(void)
{
    if(WDT_GET_TIMEOUT_INT_FLAG() == 1)
    {
        /* Clear WDT time-out interrupt flag */
        WDT_CLEAR_TIMEOUT_INT_FLAG();

        g_u8IsWDTTimeoutINT = 1;

        printf("WDT time-out interrupt occurred.\n");
    }
}

void SYS_Init(void)
{
    /*---------------------------------------------------------------------------------------------------------*/
    /* Init System Clock                                                                                       */
    /*---------------------------------------------------------------------------------------------------------*/
    /* Enable IRC22M clock */
    CLK->PWRCON |= CLK_PWRCON_IRC22M_EN_Msk;

    /* Waiting for IRC22M clock ready */
    while(!(CLK->CLKSTATUS & CLK_CLKSTATUS_IRC22M_STB_Msk));

    /* Switch HCLK clock source to HIRC */
    CLK->CLKSEL0 = CLK_CLKSEL0_HCLK_S_HIRC;

    /* Set PLL to Power-down mode and PLL_STB bit in CLKSTATUS register will be cleared by hardware.*/
    CLK->PLLCON |= CLK_PLLCON_PD_Msk;

    /* Enable XT1_OUT(PF.0) and XT1_IN(PF.1) */
    SYS->GPF_MFP &= ~(SYS_GPF_MFP_PF0_Msk | SYS_GPF_MFP_PF1_Msk);
    SYS->GPF_MFP |= SYS_GPF_MFP_PF0_XT1_OUT | SYS_GPF_MFP_PF1_XT1_IN;

    /* Enable external 12 MHz XTAL, IRC 10 kHz */
    CLK->PWRCON |= CLK_PWRCON_XTL12M_EN_Msk | CLK_PWRCON_OSC10K_EN_Msk;

    /* Enable PLL and Set PLL frequency */
    CLK->PLLCON = PLLCON_SETTING;

    /* Waiting for clock ready */
    while(!(CLK->CLKSTATUS & CLK_CLKSTATUS_XTL12M_STB_Msk));
    while(!(CLK->CLKSTATUS & CLK_CLKSTATUS_IRC10K_STB_Msk));
    while(!(CLK->CLKSTATUS & CLK_CLKSTATUS_PLL_STB_Msk));

    /* Switch HCLK clock source to PLL, STCLK to HCLK/2 */
    CLK->CLKSEL0 = CLK_CLKSEL0_STCLK_S_HCLK_DIV2 | CLK_CLKSEL0_HCLK_S_PLL;

    /* Enable peripheral clock */
    CLK->APBCLK = CLK_APBCLK_UART0_EN_Msk | CLK_APBCLK_WDT_EN_Msk;

    /* Peripheral clock source */
    CLK->CLKSEL1 = CLK_CLKSEL1_UART_S_PLL | CLK_CLKSEL1_WDT_S_LIRC;

    /* 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, TXD */
    SYS->GPB_MFP &= ~(SYS_GPB_MFP_PB0_Msk | SYS_GPB_MFP_PB1_Msk);
    SYS->GPB_MFP |= (SYS_GPB_MFP_PB0_UART0_RXD | SYS_GPB_MFP_PB1_UART0_TXD);
}

void UART0_Init(void)
{
    /*---------------------------------------------------------------------------------------------------------*/
    /* Init UART                                                                                               */
    /*---------------------------------------------------------------------------------------------------------*/
    /* Reset IP */
    SYS->IPRSTC2 |=  SYS_IPRSTC2_UART0_RST_Msk;
    SYS->IPRSTC2 &= ~SYS_IPRSTC2_UART0_RST_Msk;

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

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

    if(WDT_GET_RESET_FLAG() == 1)
    {
        /* Use PA.10 to check time-out period time */
        PA->PMD = 0xFFDFFFFF;
        PA10 = 1;

        WDT_CLEAR_RESET_FLAG();
        printf("\n\n*** WDT time-out reset occurred ***\n");
        while(1);
    }

    printf("\n\nCPU @ %d Hz\n", SystemCoreClock);
    printf("+--------------------------------------+\n");
    printf("|    WDT Time-out Reset Sample Code    |\n");
    printf("+--------------------------------------+\n\n");

    printf("# WDT Settings:\n");
    printf("  Clock source is 10 kHz; Enable interrupt; Time-out interval is 2^14 * WDT clock.\n");
    printf("# When WDT start counting, system will generate a WDT time-out interrupt after around 1.6384 s.\n");
    printf("  Measure PA.10 low period to check time-out interval and do not reload WDT counter will cause system reset.\n\n");

    /* Use PA.10 to check time-out period time */
    PA->PMD = 0xFFDFFFFF;
    PA10 = 1;
    PA10 = 0;

    /* 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();

    /* Enable WDT time-out reset function and select time-out interval to 2^14 * WDT clock then start WDT counting */
    g_u8IsWDTTimeoutINT = 0;
    WDT->WTCR = WDT_TIMEOUT_2POW14 | WDT_WTCR_WTIE_Msk | WDT_WTCR_WTRE_Msk | WDT_WTCR_WTE_Msk;

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

    while(1);
}

/*** (C) COPYRIGHT 2014~2015 Nuvoton Technology Corp. ***/
