/**************************************************************************//**
 * @file     main.c
 * @version  V3.00
 * @brief    Show how to wake up system from Power-down mode by GPIO interrupt.
 *
 * SPDX-License-Identifier: Apache-2.0
 * @copyright (C) 2018 Nuvoton Technology Corp. All rights reserved.
 ******************************************************************************/
#include <stdio.h>
#include "NuMicro.h"


/*---------------------------------------------------------------------------------------------------------*/
/*  Function for System Entry to Power Down Mode                                                           */
/*---------------------------------------------------------------------------------------------------------*/
void PowerDownFunction(void)
{
    /* Check if all the debug messages are finished */
    UART_WAIT_TX_EMPTY(UART0);

    /* Set the processor uses deep sleep as its low power mode */
    SCB->SCR |= SCB_SCR_SLEEPDEEP_Msk;

    /* Set system Power-down enabled*/
    CLK->PWRCTL |= CLK_PWRCTL_PDEN_Msk;

    /* Chip enter Power-down mode after CPU run WFI instruction */
    __WFI();
}

/**
 * @brief       GPIO PA/PB/PG/PH IRQ
 *
 * @param       None
 *
 * @return      None
 *
 * @details     The PA/PB/PG/PH default IRQ, declared in startup_M031Series.s.
 */
void GPABGH_IRQHandler(void)
{
    volatile uint32_t temp;

    /* To check if PB.3 interrupt occurred */
    if(PB->INTSRC & BIT3)
    {
        PB->INTSRC = BIT3;
        printf("PB.3 INT occurred.\n");
    }
    else
    {
        /* Un-expected interrupt. Just clear all PB interrupts */
        temp = PB->INTSRC;
        PB->INTSRC = temp;
        printf("Un-expected interrupts.\n");
    }
}

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

    /* Enable HIRC */
    CLK->PWRCTL |= CLK_PWRCTL_HIRCEN_Msk;

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

    /* Switch HCLK clock source to HIRC */
    CLK->CLKSEL0 = (CLK->CLKSEL0 & ~CLK_CLKSEL0_HCLKSEL_Msk) | CLK_CLKSEL0_HCLKSEL_HIRC;
    CLK->CLKDIV0 = (CLK->CLKDIV0 & ~CLK_CLKDIV0_HCLKDIV_Msk) | CLK_CLKDIV0_HCLK(1);

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

    /* Switch UART0 clock source to HIRC */
    CLK->CLKSEL1 = (CLK->CLKSEL1 & ~CLK_CLKSEL1_UART0SEL_Msk) | CLK_CLKSEL1_UART0SEL_HIRC;
    CLK->CLKDIV0 = (CLK->CLKDIV0 & ~CLK_CLKDIV0_UART0DIV_Msk) | CLK_CLKDIV0_UART0(1);

    /* Enable UART0 peripheral clock */
    CLK->APBCLK0 |= CLK_APBCLK0_UART0CKEN_Msk;

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

    /*----------------------------------------------------------------------*/
    /* Init I/O Multi-function                                              */
    /*----------------------------------------------------------------------*/
    /* Set GPB multi-function pins for UART0 RXD and TXD */
    SYS->GPB_MFPH = (SYS->GPB_MFPH & ~(SYS_GPB_MFPH_PB12MFP_Msk | SYS_GPB_MFPH_PB13MFP_Msk)) |
                    (SYS_GPB_MFPH_PB12MFP_UART0_RXD | SYS_GPB_MFPH_PB13MFP_UART0_TXD);

    /* Lock protected registers */
    SYS_LockReg();
}

/*----------------------------------------------------------------------*/
/* Init UART0                                                           */
/*----------------------------------------------------------------------*/
void UART0_Init(void)
{
    /* Reset UART0 */
    SYS->IPRST1 |=  SYS_IPRST1_UART0RST_Msk;
    SYS->IPRST1 &= ~SYS_IPRST1_UART0RST_Msk;

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

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

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

    printf("\n\nCPU @ %d Hz\n", SystemCoreClock);
    printf("+-------------------------------------------------------+\n");
    printf("|    GPIO Power-Down and Wake-up by PB.3 Sample Code    |\n");
    printf("+-------------------------------------------------------+\n\n");

    /* Configure PB.3 as Input mode and enable interrupt by rising edge trigger */
    PB->MODE = (PB->MODE & ~(GPIO_MODE_MODE3_Msk)) | (GPIO_MODE_INPUT << GPIO_MODE_MODE3_Pos);
    /* Configure interrupt mode of specified pin */
    PB->INTTYPE &= ~BIT3;   /* set PB3 to edge trigger interrupt */
    /* Enable interrupt function of specified pin */
    PB->INTEN = (PB->INTEN & ~(BIT3)) |         /* disable falling edge trigger interrupt */
                (BIT3<<GPIO_INTEN_RHIEN0_Pos);  /* enable  rising  edge trigger interrupt */

    NVIC_EnableIRQ(GPIO_PAPBPGPH_IRQn);

    /* Enable interrupt de-bounce function and select de-bounce sampling cycle time is 1024 clocks of LIRC clock */
    GPIO->DBCTL = GPIO_DBCTL_ICLKON_Msk | GPIO_DBCTL_DBCLKSRC_LIRC | GPIO_DBCTL_DBCLKSEL_1024;
    PB->DBEN |= BIT3;

    /* Unlock protected registers before entering Power-down mode */
    SYS_UnlockReg();

    /* Waiting for PB.3 rising-edge interrupt event */
    while(1)
    {
        printf("Enter to Power-Down. Wait PB.3 rising edge interrupt to wake up ...\n");

        /* Enter to Power-down mode */
        PowerDownFunction();

        printf("System waken-up done.\n\n");
    }
}
