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STM32独立看门狗和低功耗模式_RTC定时唤醒来喂狗

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关键字:
STM32,看门狗,振荡器,

在STM32开发中经常会用到独立看门狗(IWDG)和低功耗模式,看门狗是为了检测和解决由软件错误引起的故障,低功耗模式是为了在CPU不需要继续运行时进入到休眠模式用以节省电能。其中独立看门狗的时钟由独立的RC振荡器(STM32F10x一般为40kHz)提供,即使在主时钟出现故障时,也仍然有效,因此可以在停止和待机模式下工作。而且独立看门狗一旦启动,除了系统复位,它不能再被停止。但这样引发的一个问题是当MCU进入到低功耗模式后由于CPU停止运行无法喂狗,会导致系统频繁复位。那如何解决这个问题呢,难道独立看门狗和低功耗模式没法同时使用?

一个很好的方式是在休眠模式下通过RTC定时唤醒来喂狗,喂完够在进入继续进入到休眠模式。比如看门狗复位的时间间隔为10s。那么在进入休眠模式前设置RTC闹钟中断时间为5s。这样每隔5s唤醒一次喂一次狗。便可以很好的解决这个问题。

while(1)  

{  

// 执行任务  

Task1();  

Task2();  

// ..  

// 喂狗  

dev_iwdg_feed();  

// 进入待机模式开关  

if(m_bEnterStandByMode)  

{     

// 使能外部中断,GPIOB3,用以MCU从待机模式唤醒  

dev_exTI_enable(TRUE);  

ENTERSTOPMODE:    

// 设置RTC闹钟,5秒钟产生一次RTC闹钟中断*/  

dev_rtc_setAlarm(5);  

// 进入停止模式(低功耗),直至外部中断触发时被唤醒  

PWR_EnterSTOPMode(PWR_Regulator_LowPower, PWR_STOPEntry_WFI);  

// 是否是RTC闹钟中断唤醒  

if(dev_rtc_isAlarm())  

{  

// 喂狗  

dev_iwdg_feed();  

// 喂完狗继续进入停止模式  

goto ENTERSTOPMODE;   

}  

// 禁止外部中断   

dev_exTI_enable(FALSE);  

// 从停止模式唤醒后恢复系统时钟  

dev_clk_restore();  

}               

}  

以下是完整的参考代码:

//**********************************************************************************************       

//  STM32F10x StopMode RTC Feed Dog   

//  compiler: Keil UV3       

//  2013-01-04 , By friehood       

//**********************************************************************************************    

#include "stm32f10x_lib.h"  

#include "platform_config.h"  

staTIc Boolean g_bRTCAlarm = FALSE;  

/*******************************************************************************  

* FuncTIon Name  : RCC_Configuration  

* Description    : Configures the different system clocks.  

* Input          : None  

* Output         : None  

* Return         : None  

*******************************************************************************/  

void RCC_Configuration(void)  

{  

/* RCC system reset(for debug purpose) */  

RCC_DeInit();  

/* Enable HSE */  

RCC_HSEConfig(RCC_HSE_ON);  

/* Wait till HSE is ready */  

if(RCC_WaitForHSEStartUp() == SUCCESS)  

{  

/* Enable Prefetch Buffer */  

FLASH_PrefetchBufferCmd(FLASH_PrefetchBuffer_Enable);  

//FLASH时序控制   

//推荐值:SYSCLK = 0~24MHz   Latency=0   

//        SYSCLK = 24~48MHz  Latency=1   

//        SYSCLK = 48~72MHz  Latency=2  

//FLASH_SetLatency(FLASH_Latency_1);        //警告:修改为1会对DMA值有影响(如ADC采集值会错位)  

FLASH_SetLatency(FLASH_Latency_2);  

/* HCLK = SYSCLK */  

RCC_HCLKConfig(RCC_SYSCLK_Div1);   

/* PCLK2 = HCLK */  

RCC_PCLK2Config(RCC_HCLK_Div1);   

/* PCLK1 = HCLK/2 */  

RCC_PCLK1Config(RCC_HCLK_Div2);  

/* PLLCLK = 12MHz * 3 = 36 MHz */  

RCC_PLLConfig(RCC_PLLSource_HSE_Div1, RCC_PLLMul_3);  

/* Enable PLL */   

RCC_PLLCmd(ENABLE);  

/* Wait till PLL is ready */  

while(RCC_GetFlagStatus(RCC_FLAG_PLLRDY) == RESET)  

{  

}  

/* Select PLL as system clock source */  

RCC_SYSCLKConfig(RCC_SYSCLKSource_PLLCLK);  

/* Wait till PLL is used as system clock source */  

while(RCC_GetSYSCLKSource() != 0x08)  

{  

}  

}  

/* Enable PWR and BKP clock */  

RCC_APB1PeriphClockCmd(RCC_APB1Periph_PWR | RCC_APB1Periph_BKP, ENABLE);  

/* Enable AFIO clock */  

RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO, ENABLE);  

}  

/******************************************************************************* 

* Function Name  : NVIC_Configuration 

* Description    : Configures the nested vectored interrupt controller. 

* Input          : None 

* Output         : None 

* Return         : None 

*******************************************************************************/  

void NVIC_Configuration(void)  

{  

NVIC_InitTypeDef NVIC_InitStructure;  

#ifdef  VECT_TAB_RAM  

/* Set the Vector Table base location at 0x20000000 */  

NVIC_SetVectorTable(NVIC_VectTab_RAM, 0x0);  

#else  /* VECT_TAB_FLASH  */  

/* Set the Vector Table base location at 0x08000000 */  

NVIC_SetVectorTable(NVIC_VectTab_FLASH, 0x0);  

#endif  

/* Configure one bit for preemption priority */  

NVIC_PriorityGroupConfig(NVIC_PriorityGroup_1);  

}  

/******************************************************************************* 

* Function Name  : SysTick_Configuration 

* Description    : Configures the SysTick to generate an interrupt each 1 millisecond. 

* Input          : None 

* Output         : None 

* Return         : None 

*******************************************************************************/  

void SysTick_Configuration(void)  

{  

/* Select AHB clock(HCLK) as SysTick clock source */  

SysTick_CLKSourceConfig(SysTick_CLKSource_HCLK);  

/* Set SysTick Priority to 3 */  

NVIC_SystemHandlerPriorityConfig(SystemHandler_SysTick, 3, 0);  

/* SysTick interrupt each 1ms with HCLK equal to 72MHz */  

SysTick_SetReload(72000);  

/* Enable the SysTick Interrupt */  

SysTick_ITConfig(ENABLE);  

}  

/******************************************************************************* 

* Function Name  : Delay 

* Description    : Inserts a delay time. 

* Input          : nTime: specifies the delay time length, in milliseconds. 

* Output         : None 

* Return         : None 

*******************************************************************************/  

void Delay(u32 nTime)  

{  

/* Enable the SysTick Counter */  

SysTick_CounterCmd(SysTick_Counter_Enable);  

TimingDelay = nTime;  

while(TimingDelay != 0);  

/* Disable the SysTick Counter */  

SysTick_CounterCmd(SysTick_Counter_Disable);  

/* Clear the SysTick Counter */  

SysTick_CounterCmd(SysTick_Counter_Clear);  

}  

/******************************************************************************* 

* Function Name  : RTC_Configuration 

* Description    : Configures RTC clock source and prescaler. 

* Input          : None 

* Output : None

void RTC_Configuration(void)

{

EXTI_InitTypeDef EXTI_InitStructure;

NVIC_InitTypeDef NVIC_InitStructure;

/* RTC clock source configuration ------------------------------------------*/

/* Allow access to BKP Domain */

PWR_BackupAccessCmd(ENABLE);

/* Reset Backup Domain */

BKP_DeInit();

/* Enable the LSI OSC */

RCC_LSICmd(ENABLE);

/* Wait till LSI is ready */

while (RCC_GetFlagStatus(RCC_FLAG_LSIRDY) == RESET){}

/* Select the RTC Clock Source */

RCC_RTCCLKConfig(RCC_RTCCLKSource_LSI);

/* Enable the RTC Clock */

RCC_RTCCLKCmd(ENABLE);

/* RTC configuration -------------------------------------------------------*/

/* Wait for RTC APB registers synchronisation */

RTC_WaitForSynchro();

/* Set RTC prescaler: set RTC period to 1sec */

RTC_SetPrescaler(40000);

/* Wait until last write operation on RTC registers has finished */

RTC_WaitForLastTask();

/* Enable the RTC Alarm interrupt */

RTC_ITConfig(RTC_IT_ALR, ENABLE);

/* Wait until last write operation on RTC registers has finished */

RTC_WaitForLastTask();

/* Configure EXTI Line17(RTC Alarm) to generate an interrupt on rising edge */

EXTI_ClearITPendingBit(EXTI_Line17);

EXTI_InitStructure.EXTI_Line = EXTI_Line17;

EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt;

EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Rising;

EXTI_InitStructure.EXTI_LineCmd = ENABLE;

EXTI_Init(&EXTI_InitStructure);

/* Enable the RTC Interrupt */

NVIC_InitStructure.NVIC_IRQChannel = RTCAlarm_IRQChannel;

NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;

NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;

NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;

NVIC_Init(&NVIC_InitStructure);

}

/*******************************************************************************

* Function Name : RTCAlarm_IRQHandler

* Description : This function handles RTC Alarm interrupt request.

* Input : None

* Output : None

* Return : None

*******************************************************************************/

void RTCAlarm_IRQHandler(void)

{

if(RTC_GetITStatus(RTC_IT_ALR) != RESET)

{

/* Set the RTC alarm flag */

g_bRTCAlarm = TRUE;

/* Clear EXTI line17 pending bit */

EXTI_ClearITPendingBit(EXTI_Line17);

/* Check if the Wake-Up flag is set */

if(PWR_GetFlagStatus(PWR_FLAG_WU) != RESET)

{

/* Clear Wake Up flag */

PWR_ClearFlag(PWR_FLAG_WU);

}

/* Wait until last write operation on RTC registers has finished */

RTC_WaitForLastTask();

/* Clear RTC Alarm interrupt pending bit */

RTC_ClearITPendingBit(RTC_IT_ALR);

/* Wait until last write operation on RTC registers has finished */

RTC_WaitForLastTask();

}

}

/*******************************************************************************

* Function Name : dev_rtc_setAlarm

* Description : 设置RTC闹钟。

* Input : 闹钟时间

* Output : None

* Return : None

*******************************************************************************/

void dev_rtc_setAlarm(u32 AlarmValue)

{

/* Clear the RTC SEC flag */

RTC_ClearFlag(RTC_FLAG_SEC);

/* Wait clear RTC flag sccess */

while(RTC_GetFlagStatus(RTC_FLAG_SEC) == RESET);

/* Wait until last write operation on RTC registers has finished */

RTC_WaitForLastTask();

/* Sets the RTC alarm value */

RTC_SetAlarm(RTC_GetCounter() + AlarmValue);

/* Wait until last write operation on RTC registers has finished */

RTC_WaitForLastTask();

}

/*******************************************************************************

* Function Name : dev_rtc_isAlarm

* Description : RTC闹钟是否触发

* Input : None

* Output : None

* Return : TRUE:已触发,FALSE,未触发

*******************************************************************************/

Boolean dev_rtc_isAlarm(void)

{

if(g_bRTCAlarm)

{

/* Clear the RTC alarm flag */

g_bRTCAlarm = FALSE;

return TRUE;

}

return FALSE;

}

void dev_iwdg_init(void)

{

/* Enable write access to IWDG_PR and IWDG_RLR registers */

IWDG_WriteAccessCmd(IWDG_WriteAccess_Enable);

/* IWDG counter clock: 40KHz(LSI) / 256 = 0.15625 KHz */

IWDG_SetPrescaler(IWDG_Prescaler_256);

/* Set counter reload value to 1562 */

IWDG_SetReload(1562); // 10s

/* Reload IWDG counter */

IWDG_ReloadCounter();

/* Enable IWDG (the LSI oscillator will be enabled by hardware) */

IWDG_Enable();

}

void dev_iwdg_feed(void)

{

IWDG_ReloadCounter();

}

/*******************************************************************************

* Function Name : dev_clk_restore

* Description : Restore system clock after wake-up from STOP: enable HSE, PLL

* and select PLL as system clock source.

* Input : None

* Output : None

* Return : None

*******************************************************************************/

void dev_clk_restore(void)

{

/* Enable HSE */

RCC_HSEConfig(RCC_HSE_ON);

/* Wait till HSE is ready */

HSEStartUpStatus = RCC_WaitForHSEStartUp();

if(HSEStartUpStatus == SUCCESS)

{

/* Enable PLL */

RCC_PLLCmd(ENABLE);

/* Wait till PLL is ready */

while(RCC_GetFlagStatus(RCC_FLAG_PLLRDY) == RESET)

{

}

/* Select PLL as system clock source */

RCC_SYSCLKConfig(RCC_SYSCLKSource_PLLCLK);

/* Wait till PLL is used as system clock source */

while(RCC_GetSYSCLKSource() != 0x08)

{

}

}

}

/*******************************************************************************

* Function Name : EXTI_Configuration

* Description : Configures EXTI Line3.

* Input : None

* Output : None

* Return : None

*******************************************************************************/

void EXIT_Configuration(void)

{

EXTI_InitTypeDef EXTI_InitStructure;

GPIO_EXTILineConfig(GPIO_PortSourceGPIOB,GPIO_PinSource3);

EXTI_ClearITPendingBit(EXTI_Line3);

EXTI_InitStructure.EXTI_Line = EXTI_Line3;

EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt;

EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Falling;

EXTI_InitStructure.EXTI_LineCmd = ENABLE;

EXTI_Init(&EXTI_InitStructure);

}

void dev_exti_enable(Boolean bEnable)

{

NVIC_InitTypeDef NVIC_InitStructure;

/* Clear the Key Button EXTI line pending bit */

EXTI_ClearITPendingBit(EXTI_Line3);

NVIC_ClearIRQChannelPendingBit(EXTI3_IRQChannel);

NVIC_InitStructure.NVIC_IRQChannel = EXTI3_IRQChannel;

NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;

NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;

NVIC_InitStructure.NVIC_IRQChannelCmd = bEnable ? ENABLE : DISABLE;

NVIC_Init(&NVIC_InitStructure);

}

/*******************************************************************************

* Function Name : main

* Description : Main program.

* Input : None

* Output : None

* Return : None

*******************************************************************************/

int main(void)

{

/* System Clocks Configuration */

RCC_Configuration();

/* NVIC configuration */

NVIC_Configuration();

/* Configure RTC clock source and prescaler */

RTC_Configuration();

/* Configure the SysTick to generate an interrupt each 1 millisecond */

SysTick_Configuration();

/* Configures EXTI Line3 */

EXIT_Configuration();

/* IWDG initialize*/

dev_iwdg_init();

while(1)

{

// 执行任务

Task1();

Task2();

// 。。

// 喂狗

dev_iwdg_feed();

// 进入待机模式开关

if(m_bEnterStandByMode)

{

// 使能外部中断,GPIOB3,用以MCU从待机模式唤醒

dev_exti_enable(TRUE);

ENTERSTOPMODE:

// 设置RTC闹钟,5秒钟产生一次RTC闹钟中断*/

dev_rtc_setAlarm(5);

// 进入停止模式(低功耗),直至外部中断触发时被唤醒

PWR_EnterSTOPMode(PWR_Regulator_LowPower, PWR_STOPEntry_WFI);

// 是否是RTC闹钟中断唤醒

if(dev_rtc_isAlarm())

{

// 喂狗

dev_iwdg_feed();

// 喂完狗继续进入停止模式

goto ENTERSTOPMODE;

}

// 禁止外部中断

dev_exti_enable(FALSE);

// 从停止模式唤醒后恢复系统时钟

dev_clk_restore();

}

}

}

来源:网络整理   作者:工程师d  2018/5/18 1:55:00
栏目: [ STM32单片机看门狗]

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