/**************************************************************************//**
 * @file     main.c
 * @version  V3.00
 * $Revision: 6 $
 * $Date: 15/05/22 2:39p $
 * @brief    Show how to reload the WWDT counter value.
 * @note
 * Copyright (C) 2013 Nuvoton Technology Corp. All rights reserved.
 ******************************************************************************/
#include <stdio.h>
#include "M051Series.h"

#define PLLCON_SETTING      CLK_PLLCON_50MHz_HXT
#define PLL_CLOCK           50000000


/*---------------------------------------------------------------------------------------------------------*/
/* Global Interface Variables Declarations                                                                 */
/*---------------------------------------------------------------------------------------------------------*/
extern int IsDebugFifoEmpty(void);
volatile uint32_t g_u32WWDTINTCount = 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_M051Series.s.
 */
void WDT_IRQHandler(void)
{
    if((WWDT->WWDTSR & WWDT_WWDTSR_WWDTIF_Msk) == WWDT_WWDTSR_WWDTIF_Msk)
    {
        /* Clear WWDT compare match interrupt flag */
        WWDT->WWDTSR = WWDT_WWDTSR_WWDTIF_Msk;

        g_u32WWDTINTCount++;

        if(g_u32WWDTINTCount < 10)
        {
            /* To reload the WWDT counter value to 0x3F */
            WWDT->WWDTRLD = 0x00005AA5;
        }

        printf("WWDT compare match interrupt occurred. (%d)\n", g_u32WWDTINTCount);
    }
}

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 external 12 MHz XTAL, IRC10K */
    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_PLL_STB_Msk));
    while(!(CLK->CLKSTATUS & CLK_CLKSTATUS_XTL12M_STB_Msk));
    while(!(CLK->CLKSTATUS & CLK_CLKSTATUS_IRC10K_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->CLKSEL2 = CLK_CLKSEL2_WWDT_S_HCLK_DIV2048;

    /* Update System Core Clock */
    /* User can use SystemCoreClockUpdate() to calculate PllClock, SystemCoreClock and CycylesPerUs automatically. */
    PllClock        = PLL_CLOCK;
    SystemCoreClock = PLL_CLOCK / 1;
    CyclesPerUs     = PLL_CLOCK / 1000000;

    /*---------------------------------------------------------------------------------------------------------*/
    /* Init I/O Multi-function                                                                                 */
    /*---------------------------------------------------------------------------------------------------------*/
    /* Set P3 multi-function pins for UART0 RXD, TXD */
    SYS->P3_MFP &= ~(SYS_MFP_P30_Msk | SYS_MFP_P31_Msk);
    SYS->P3_MFP |=  (SYS_MFP_P30_RXD0 | SYS_MFP_P31_TXD0);
}

void UART0_Init(void)
{
    /*---------------------------------------------------------------------------------------------------------*/
    /* Init UART                                                                                               */
    /*---------------------------------------------------------------------------------------------------------*/
    /* Reset UART */
    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)
{
    volatile uint32_t u32InitCount;
    double dPeriodTime;

    /* 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((WWDT->WWDTSR & WWDT_WWDTSR_WWDTRF_Msk) == WWDT_WWDTSR_WWDTRF_Msk)
    {
        WWDT->WWDTSR = WWDT_WWDTSR_WWDTRF_Msk;
        printf("\n*** WWDT time-out reset occurred ***\n");
    }
#if !( __GNUC__ )
    printf("\n\nCPU @ %d Hz\n", SystemCoreClock);
#endif
    printf("+-------------------------------------------------+\n");
    printf("|    WWDT Compare March Interrupt Sample Code    |\n");
    printf("+-------------------------------------------------+\n\n");
    printf("# WWDT Settings: \n");
#if !( __GNUC__ )
    dPeriodTime = (((double)(1000000 * 2048) / (double)SystemCoreClock) * 1024) * 32;
    printf("  Clock source is HCLK/2048(%d Hz); Enable interrupt; Window Compare value is 32;\n", SystemCoreClock / 2048);
#endif
    printf("  Select max WWDT time-out period is 1024 * (64 * WWDT_clock);\n");
#if !( __GNUC__ )
    printf("# When WWDT start counting, system will generate first WWDT compare match interrupt after %.2f us.\n", dPeriodTime);
#endif
    printf("  1.) reload WWDT counter value to 0x3F when WWDT interrupt count less than 10 to avoid WWDT reset occurred.\n");
    printf("  2.) system will be reset by WWDT counting time-out while WWDT interrupt count reaches to 10.\n\n");

    u32InitCount = g_u32WWDTINTCount = 0;

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

    /* Configure WWDT compare value is 32; max time-out period is 1024*(64*WWDT_clk) and enable WWDT interrupt then start WWDT counting */
    /* Note: WWDTCR register can be written only once after chip is powered on or reset */
    WWDT->WWDTCR = WWDT_PRESCALER_1024 |
                   (32 << WWDT_WWDTCR_WINCMP_Pos) |
                   WWDT_WWDTCR_WWDTIE_Msk |
                   WWDT_WWDTCR_WWDTEN_Msk;

    printf("[WWDTCR: 0x%08X]\n\n", WWDT->WWDTCR);

    while(1);
}

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