
/******************************************************************************
 * @file     main.c
 * @version  V3.00
 * $Revision: 1 $
 * $Date: 14/10/17 8:32p $
 * @brief    Demonstrate how to wake up from Power-down mode by ACMP wake-up function.
 *
 * @note
 * @copyright SPDX-License-Identifier: Apache-2.0
 * @copyright Copyright (C) 2014 Nuvoton Technology Corp. All rights reserved.
*****************************************************************************/
#include <stdio.h>
#include "NUC029xAN.h"


/* Function prototype declaration */
void SYS_Init(void);
void UART_Init(void);
void PowerDownFunction(void);
int IsDebugFifoEmpty(void);
extern char GetChar(void);

int32_t main(void)
{
    uint32_t u32DelayCount;

    /* Unlock protected registers */
    SYS_UnlockReg();
    /* Init System, IP clock and multi-function I/O. */
    SYS_Init();
    /* Lock protected registers */
    SYS_LockReg();

    /* Init UART for print message */
    UART_Init();

    printf("\n\n");
    printf("+---------------------------------------+\n");
    printf("|        NUC029 ACMP Sample Code        |\n");
    printf("+---------------------------------------+\n");

    printf("\nThis sample code demonstrates ACMP0 wake-up function. Using ACMP0_P (P1.5) as ACMP0\n");
    printf("positive input and using internal band-gap voltage as the negative input.\n");
    printf("The compare result reflects on ACMP0_O (P3.6)\n");

    printf("When the voltage of the positive input is greater than the voltage of the negative input,\n");
    printf("the analog comparator outputs logical one; otherwise, it outputs logical zero.\n");
    printf("This chip will be waked up from power down mode when detecting a transition of analog comparator's output.\n");
    printf("Press any key to enter power down mode ...");
    GetChar();
    printf("\n");

    /* Select band-gap voltage as the source of ACMP negative input */
    ACMP_SET_NEG_SRC(ACMP01, 0, ACMP_CR_VNEG_BANDGAP);
    /* Enable ACMP0 */
    ACMP_ENABLE(ACMP01, 0);
    __NOP();
    for(u32DelayCount = 0; u32DelayCount < 100; u32DelayCount++); /* For ACMP setup time */
    __NOP();
    /* Clear ACMP 0 interrupt flag */
    ACMP_CLR_INT_FLAG(ACMP01, 0);

    /* Enable interrupt */
    ACMP_ENABLE_INT(ACMP01, 0);
    /* Enable ACMP01 interrupt */
    NVIC_EnableIRQ(ACMP01_IRQn);

    /* To program PWRCON register, it needs to disable register protection first. */
    SYS_UnlockReg();
    PowerDownFunction();
    printf("Wake up by ACMP0!\n");

    while(1);

}

void ACMP01_IRQHandler(void)
{
    printf("\nACMP0 interrupt!\n");
    /* Disable interrupt */
    ACMP_DISABLE_INT(ACMP01, 0);
    /* Clear ACMP 0 interrupt flag */
    ACMP_CLR_INT_FLAG(ACMP01, 0);
}


void SYS_Init(void)
{
	uint32_t u32TimeOutCnt;

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

    /* Enable external 12MHz XTAL */
    CLK->PWRCON |= CLK_PWRCON_XTL12M_EN_Msk;

    /* Waiting for clock ready */
    u32TimeOutCnt = __HIRC;
    while(!(CLK->CLKSTATUS & CLK_CLKSTATUS_XTL12M_STB_Msk))
		if(--u32TimeOutCnt == 0) break;

    /* Select HXT as the clock source of UART */
    CLK->CLKSEL1 &= (~CLK_CLKSEL1_UART_S_Msk);

    /* Enable UART and ACMP clock */
    CLK->APBCLK = CLK_APBCLK_UART0_EN_Msk | CLK_APBCLK_ACMP01_EN_Msk;

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


    /*---------------------------------------------------------------------------------------------------------*/
    /* Init I/O Multi-function                                                                                 */
    /*---------------------------------------------------------------------------------------------------------*/
    /* Set P1.5 multi-function pin for ACMP0 positive input pin */
    SYS->P1_MFP &= ~SYS_MFP_P15_Msk;
    SYS->P1_MFP |= SYS_MFP_P15_ACMP0_P;

    /* Set P3 multi-function pins for UART0 RXD, TXD and ACMP0 output */
    SYS->P3_MFP &= ~(SYS_MFP_P30_Msk | SYS_MFP_P31_Msk | SYS_MFP_P36_Msk);
    SYS->P3_MFP |= (SYS_MFP_P30_RXD0 | SYS_MFP_P31_TXD0 | SYS_MFP_P36_ACMP0_O);


    /* Disable digital input path of analog pin ACMP0_P to prevent leakage */
    P1->OFFD |= (1 << 5) << GPIO_OFFD_OFFD_Pos;
}

void UART_Init(void)
{
    /* Word length is 8 bits; 1 stop bit; no parity bit. */
    UART0->LCR = UART_LCR_WLS_Msk;
    /* Using mode 2 calculation: UART bit rate = UART peripheral clock rate / (BRD setting + 2) */
    /* UART peripheral clock rate 12MHz; UART bit rate 115200 bps. */
    /* 12000000 / 115200 bps ~= 104 */
    /* 104 - 2 = 0x66. */
    UART0->BAUD = UART_BAUD_DIV_X_EN_Msk | UART_BAUD_DIV_X_ONE_Msk | (0x66);
}

void PowerDownFunction(void)
{
    uint32_t u32TimeOutCnt;

    printf("\nSystem enter power-down mode ... ");

    /* To check if all the debug messages are finished */
    u32TimeOutCnt = SystemCoreClock; /* 1 second time-out */
    while(IsDebugFifoEmpty() == 0)
        if(--u32TimeOutCnt == 0) break;

    /* Deep sleep mode is selected */
    SCB->SCR = SCB_SCR_SLEEPDEEP_Msk;

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

    __WFI();
}

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