另外一个功能就是唤醒断电模式的系统了。就好比关机或者休眠后的唤醒。
/******************************************************************************
* @file main.c
* @version V3.00
* $Revision: 2 $
* $Date: 15/05/22 2:58p $
* @brief Show how to wake up MCU from Power-down mode by ACMP wake-up function.
*
* @note
* Copyright (C) 2014 Nuvoton Technology Corp. All rights reserved.
*****************************************************************************/
#include <stdio.h>
#include "M051Series.h"
/* Function prototype declaration */
void SYS_Init(void);
void PowerDownFunction(void);
int IsDebugFifoEmpty(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();
/* Configure UART0: 115200, 8-bit word, no parity bit, 1 stop bit. */
UART_Open(UART0, 115200);
printf("\n\n");
printf("+---------------------------------------+\n");
printf("| M051 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");
/* Configure ACMP0. Enable ACMP0 and select internal reference voltage as negative input. */
ACMP_Open(ACMP01, 0, ACMP_CR_VNEG_BANDGAP, ACMP_CR_HYSTERESIS_DISABLE);
__NOP();
for(u32DelayCount = 0; u32DelayCount < 100; u32DelayCount++); /* For ACMP setup time */
__NOP();
/* Clear ACMP 0 interrupt flag */
ACMP_CLR_INT_FLAG(ACMP01, 0);
/* Enable ACMP0 interrupt function */
ACMP_ENABLE_INT(ACMP01, 0);
/* Enable ACMP01 interrupt */
NVIC_EnableIRQ(ACMP01_IRQn);
/* To program PWRCTL 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)
{
/*---------------------------------------------------------------------------------------------------------*/
/* Init System Clock */
/*---------------------------------------------------------------------------------------------------------*/
/* Enable external 12MHz XTAL */
CLK_EnableXtalRC(CLK_PWRCON_XTL12M_EN_Msk);
/* Waiting for clock ready */
CLK_WaitClockReady(CLK_CLKSTATUS_XTL12M_STB_Msk);
/* Select HXT as the clock source of UART */
CLK_SetModuleClock(UART0_MODULE, CLK_CLKSEL1_UART_S_HXT, CLK_CLKDIV_UART(1));
/* Enable UART peripheral clock */
CLK_EnableModuleClock(UART0_MODULE);
/* Enable ACMP01 peripheral clock */
CLK_EnableModuleClock(ACMP01_MODULE);
/* 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_ACMP0_P;
/* Disable digital input path of analog pin ACMP0_P to prevent leakage */
GPIO_DISABLE_DIGITAL_PATH(P1, BIT5);
/* Set P3 multi-function pins for UART0 RXD, TXD and ACMP0 output */
SYS->P3_MFP = SYS_MFP_P30_RXD0 | SYS_MFP_P31_TXD0 | SYS_MFP_P36_ACMP0_O;
}
void PowerDownFunction(void)
{
printf("\nSystem enter power-down mode ... ");
/* To check if all the debug messages are finished */
while(IsDebugFifoEmpty() == 0);
/* Deep sleep mode is selected */
SCB->SCR = SCB_SCR_SLEEPDEEP_Msk;
/* To program PWRCTL 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. ***/
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