/**************************************************************************//**
 * @file     main.c
 * @version  V2.00
 * $Revision: 5 $
 * $Date: 15/01/16 11:44a $
 * @brief    Use WDT time-out interrupt event to wake-up system.
 * @note
 * @copyright SPDX-License-Identifier: Apache-2.0
 * @copyright Copyright (C) 2018 Nuvoton Technology Corp. All rights reserved.
 ******************************************************************************/
#include <stdio.h>
#include "NUC029xDE.h"

#define PLLCON_SETTING      CLK_PLLCON_50MHz_HXT
#define PLL_CLOCK           50000000


/*---------------------------------------------------------------------------------------------------------*/
/* Global Interface Variables Declarations                                                                 */
/*---------------------------------------------------------------------------------------------------------*/
extern int IsDebugFifoEmpty(void);
volatile uint8_t g_u8IsWDTWakeupINT = 0;


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

    printf("System 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 PWRCON register, it needs to disable register protection first. */
    CLK->PWRCON = (CLK->PWRCON & ~(CLK_PWRCON_PWR_DOWN_EN_Msk | CLK_PWRCON_PD_WAIT_CPU_Msk)) |
                  CLK_PWRCON_PD_WAIT_CPU_Msk | CLK_PWRCON_PD_WU_INT_EN_Msk;
    CLK->PWRCON |= CLK_PWRCON_PWR_DOWN_EN_Msk;

    __WFI();
}

/**
 * @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_NUC029xDE.s.
 */
void WDT_IRQHandler(void)
{
    if((WDT_GET_TIMEOUT_INT_FLAG() == 1) && (WDT_GET_TIMEOUT_WAKEUP_FLAG() == 1))
    {
        /* Clear WDT time-out interrupt and wake-up flag */
        WDT_CLEAR_TIMEOUT_INT_FLAG();
        WDT_CLEAR_TIMEOUT_WAKEUP_FLAG();

        g_u8IsWDTWakeupINT = 1;

        printf("WDT time-out wake-up 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 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_CLKSEL1_WDT_S_LIRC;

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

    /*---------------------------------------------------------------------------------------------------------*/
    /* Init I/O Multi-function                                                                                 */
    /*---------------------------------------------------------------------------------------------------------*/
    /* Set PB multi-function pins for UART0 RXD and 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)
{
    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("CPU @ %d Hz\n", SystemCoreClock);
    printf("+----------------------------------------------+\n");
    printf("|    WDT Power-down and Wake-up Sample Code    |\n");
    printf("+----------------------------------------------+\n\n");

    printf("# WDT Settings:\n");
    printf("    - Clock source is 10 kHz                \n");
    printf("    - Time-out interval is 2^14 * WDT clock \n");
    printf("      (around 1.6384 second)                \n");
    printf("    - Interrupt enable                      \n");
    printf("    - Wake-up function enable               \n");
    printf("# System will generate a WDT time-out interrupt event after around 1.6384 second, \n");
    printf("    and will be wake up from power-down mode also.\n");
    printf("    (Use PA.0 low period time to check WDT time-out interval)\n\n");

    /* Use PA.0 to check time-out period time */
    PA->PMD = 0xFFFFFFFD;
    PA0 = 1;
    PA0 = 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 wake-up function and select time-out interval to 2^14 * WDT clock then start WDT counting */
    g_u8IsWDTWakeupINT = 0;
    WDT->WTCR = WDT_TIMEOUT_2POW14 | WDT_WTCR_WTIE_Msk | WDT_WTCR_WTWKE_Msk | WDT_WTCR_WTE_Msk;

    /* Enable WDT interrupt function */
    WDT_EnableInt();

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

    /* System entry into Power-down Mode */
    PowerDownFunction();

    /* Check if WDT time-out interrupt and wake-up interrupt flag occurred */
    u32TimeOutCnt = SystemCoreClock; /* 1 second time-out */
    while(1)
    {
        if(((CLK->PWRCON & CLK_PWRCON_PD_WU_STS_Msk) == CLK_PWRCON_PD_WU_STS_Msk) && (g_u8IsWDTWakeupINT == 1))
            break;

        if(--u32TimeOutCnt == 0)
        {
            printf("Wait for System or WDT interrupt time-out!\n");
            break;
        }
    }

    PA0 = 1;

    printf("System has been wake-up done.\n");

    /* Clear Power-down wake-up interrupt flag */
    CLK->PWRCON |= CLK_PWRCON_PD_WU_STS_Msk;

    /* Disable WDT counting */
    WDT_Close();

    while(1);
}

/*** (C) COPYRIGHT 2018 Nuvoton Technology Corp. ***/
