STM32 study notes (ten)

Independent watchdog experiment of STM32F103ZET6

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Preface

The learning of STM32 can be divided into 3 versions.
1. Register version
2. Library function version
3. HAL library version
Due to personal reasons, I choose the library function version to learn STM32.

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Tip: Problems such as software installation will not be explained! ! !

One, watchdog related overview

1. Concept

2. Principle

2. Related registers

1. Key value register (IWDG_KR)

2. Prescaler register (IWDG_PR)

3. Reload register (IWDG_RLR)

4. Status register (IWDG_SR)

Three, operation steps

1. Independent watchdog timeout calculation

2. Operation steps

Fourth, the program source code

1.iwdg.h

code show as below:

#ifndef __IWDG_H
#define __IWDG_H

#include "sys.h"

void IWDG_Init(u8 prer,u16 rlr);

#endif

2.iwdg.c

code show as below:

#include "iwdg.h"

void IWDG_Init(u8 prer,u16 rlr)
{
    
    
	IWDG_WriteAccessCmd(IWDG_WriteAccess_Enable);//取消寄存器写保护
	IWDG_SetPrescaler(prer);//设置独立看门狗的预分频系数
	IWDG_SetReload(rlr);//设置看门狗重装载值
	IWDG_Enable();//使能看门狗
}

3.main.c

code show as below:

#include "stm32f10x.h"
#include "led.h"
#include "delay.h"
#include "beep.h"
#include "key.h"
#include "usart.h"
#include "exti.h"
#include "iwdg.h"


int main(void)
{
    
    
	NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);
	delay_init();
    LED_Init();
	Beep_Init();
	KEY_Init();
	uart_init(115200);
	EXTIX_Init();
	IWDG_Init(4,625);//1s     1000ms=4*2^4/40*rlr
	delay_ms(200);
	LED1=0;
	while(1)
	{
    
    
		if(KEY_SCAN(1)==KEY0_PRES)
		{
    
    
			IWDG_ReloadCounter();
		}
	}	
}

5. Experimental results

When there is no operation, LED0 lights up every 200ms, and the reset operation is always performed;
when the KEY0 button is pressed once, it is equivalent to "feeding the dog" once, and the reset operation is not performed at this time;
when the KEY0 button is kept pressed, the LED0 is off. It has been "feeding the dog" at the time, and the reset operation has not been possible;

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to sum up

As long as you write 0XAAAA to IWDG_KR once within one second, it will not cause the watchdog to reset (of course, multiple writes are also possible).