/**************************************************************************//**
 * @file     main.c
 * @version  V3.00
 * $Revision: 2 $
 * $Date: 16/10/25 4:27p $
 * @brief
 *           Show how to use voltage detector to detect pin input voltage.
 *
 * @note
 * 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


/*---------------------------------------------------------------------------------------------------------*/
/*  Brown Out Detector IRQ Handler                                                                         */
/*---------------------------------------------------------------------------------------------------------*/
void BOD_IRQHandler(void)
{
    /* Check if voltage detector interrupt happen */
    if( SYS->BODCTL & SYS_BODCTL_VDETIF_Msk )
    {
        /* Clear voltage detector interrupt flag */
        SYS->BODCTL |= SYS_BODCTL_VDETIF_Msk;
        
        if(SYS->BODCTL & SYS_BODCTL_VDETOUT_Msk)
            printf("The input voltage is lower than Bandgap.\n");
        else
            printf("The input voltage is higher than Bandgap.\n");            
    }

}

void SYS_Init(void)
{

    /*---------------------------------------------------------------------------------------------------------*/
    /* Init System Clock                                                                                       */
    /*---------------------------------------------------------------------------------------------------------*/

    /* Enable HIRC clock (Internal RC 22.1184MHz) */
    CLK->PWRCTL |= CLK_PWRCTL_HIRCEN_Msk;

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

    /* Select HCLK clock source as HIRC and HCLK clock divider as 1 */
    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 PLL to Power-down mode */
    CLK->PLLCTL |= CLK_PLLCTL_PD_Msk;

    /* Enable HXT clock (external XTAL 12MHz) */
    CLK->PWRCTL |= CLK_PWRCTL_HXTEN_Msk;

    /* Wait for HXT clock ready */
    while(!(CLK->STATUS & CLK_STATUS_HXTSTB_Msk));

    /* Set core clock as PLL_CLOCK from PLL */
    CLK->PLLCTL = PLLCTL_SETTING;
    while(!(CLK->STATUS & CLK_STATUS_PLLSTB_Msk));
    CLK->CLKSEL0 = (CLK->CLKSEL0 & (~CLK_CLKSEL0_HCLKSEL_Msk)) | CLK_CLKSEL0_HCLKSEL_PLL;

    /* Update System Core Clock */
    PllClock        = PLL_CLOCK;            // PLL
    SystemCoreClock = PLL_CLOCK / 1;        // HCLK
    CyclesPerUs     = PLL_CLOCK / 1000000;  // For CLK_SysTickDelay()

    /* Enable UART module clock */
    CLK->APBCLK0 |= CLK_APBCLK0_UART0CKEN_Msk;

    /* Select UART module clock source as HXT and UART module clock divider as 1 */
    CLK->CLKSEL1 = (CLK->CLKSEL1 & (~CLK_CLKSEL1_UARTSEL_Msk)) | CLK_CLKSEL1_UARTSEL_HXT;
    CLK->CLKDIV0 = (CLK->CLKDIV0 & (~CLK_CLKDIV0_UARTDIV_Msk)) | CLK_CLKDIV0_UART(1);

    /*---------------------------------------------------------------------------------------------------------*/
    /* Init I/O Multi-function                                                                                 */
    /*---------------------------------------------------------------------------------------------------------*/

    /* Set PD multi-function pins for UART0 RXD(PD.0) and TXD(PD.1) */
    SYS->GPD_MFPL = (SYS->GPD_MFPL & (~SYS_GPD_MFPL_PD0MFP_Msk)) | SYS_GPD_MFPL_PD0MFP_UART0_RXD;
    SYS->GPD_MFPL = (SYS->GPD_MFPL & (~SYS_GPD_MFPL_PD1MFP_Msk)) | SYS_GPD_MFPL_PD1MFP_UART0_TXD;

    /* Set PB multi-function pins for VDET_P0(PB.0) */
    SYS->GPB_MFPL = (SYS->GPB_MFPL & (~SYS_GPB_MFPL_PB0MFP_Msk)) | SYS_GPB_MFPL_PB0MFP_VDET_P0;

}

void UART0_Init()
{
    /*---------------------------------------------------------------------------------------------------------*/
    /* Init UART                                                                                               */
    /*---------------------------------------------------------------------------------------------------------*/
    /* 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(__HXT, 115200);
    UART0->LINE = UART_WORD_LEN_8 | UART_PARITY_NONE | UART_STOP_BIT_1;
}

/*---------------------------------------------------------------------------------------------------------*/
/*  Main Function                                                                                          */
/*---------------------------------------------------------------------------------------------------------*/
int32_t 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();

    printf("\n\nCPU @ %d Hz\n", SystemCoreClock);
    printf("+------------------------------------------------+\n");
    printf("|       NUC126 Voltage Detector Sample Code      |\n");
    printf("+------------------------------------------------+\n");

    printf("Change VDET_P0(PB.0) input voltage.\n");
    printf("The voltage detector interrupt is requested when the input voltage \nis dropped down or raised up through the Bandgap voltage(1.2V).\n\n");
    UART_WAIT_TX_EMPTY(DEBUG_PORT);    
    
    /* Select voltage detector external input voltage pin as VDET_P0(PB.0) */
    SYS->BODCTL &= ~SYS_BODCTL_VDETPINSEL_Msk;           

    /* Enable voltage detector function */
    SYS->BODCTL |= SYS_BODCTL_VDETEN_Msk;   

    /* Enable voltage detector interrupt function */
    SYS->BODCTL |= SYS_BODCTL_VDETIEN_Msk;
    NVIC_EnableIRQ(BOD_IRQn);    

    /* Wait for voltage detector interrupt happen */
    while(1);

}

