STM32__ 03 - beginner timer

One ,TIM brief introduction

TIM The essence of is the counter , Count the input clock , The reference clock is the main frequency 72MHZ, Without frequency division, it can generate 72M Pulse .TIM Sub advanced , Universal , Basic timer , I'm using f102c8t6 Only TIM1~TIM4 Four timers , among TIM1 For advanced timer , Others are general timers , This time mainly focuses on the general timer .

1, General timer internal structure

On the left is the clock input , This time we mainly understand TIMx_ETR External clock and internal clock TIMxCLK,TIMx_CH1, Capture... For input , This time does not involve .

The above structure is too complex. Here we refer to B A picture made by Jiangke University

For this picture , We just need to initialize the timer from left to right

2, Initialize the timer

1） First, enable the internal clock . Turn on TIM2( Used this time is TIM) The clock , Use internal clock mode .

The functions used are ：

RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2,ENABLE);

Both basic and general timers are connected to APB1 Bus , The advanced timer is connected to APB2 Bus .

TIM_InternalClockConfig(TIM2);

Use the internal clock , Even if this function is not called, the system uses the internal clock by default .

2） Configuration of time base unit , And configuration GPIO be similar , It is to configure structural variables

TIM_TimeBaseInitTypeDef TIM_TimerBaseStructure;

Define the structure variable name

TIM_TimerBaseStructure.TIM_ClockDivision=TIM_CKD_DIV1;

The clock frequency division , Not used here .

TIM_TimerBaseStructure.TIM_CounterMode=TIM_CounterMode_Up ;

counter mode , Here, select the normal up count

TIM_TimerBaseStructure.TIM_Period=10000-1;

Yes ARR Automatic reloader for configuration

TIM_TimerBaseStructure.TIM_Prescaler=7200-1;

Yes PSC The prescaler is configured

Be careful ： Here we use a timed one second operation , You can refer to the formula

 -1 To eliminate errors , We can understand that , The frequency of the internal clock is 72MHZ, First use the prescaler to divide into 7200 Share , So each is 10000HZ, Then we use a capacity of 10000 To calculate the pulse ,10000HZ Generate... For one second 10000 Pulse , In this way, the counter is filled up in one second , Create spillover .

TIM_TimerBaseStructure.TIM_RepetitionCounter=0;

Repeat counter , Advanced timer , We have... Here 0.

TIM_TimeBaseInit(TIM2,&TIM_TimerBaseStructure);

Call initialization function , Complete the configuration of time base unit

3） Interrupt enable

TIM_ClearFlag(TIM2,TIM_FLAG_Update);

This function clears the interrupt flag bit , Why this extra step ？ We can have a look TIM_TimeBaseInit（） The definition of

Generate an update event immediately to reload the prescaler and repeat counter values , It can be understood as , An update event will be generated immediately after initializing the time base unit , Cause interrupt flag position 1, Enter the interrupt function immediately after reset , Will cause the program to run one step ahead , So don't forget this step after initializing the time base unit .
TIM_ITConfig(TIM2,TIM_IT_Update,ENABLE);

Update interrupted to NVIC

4）NVIC Configuration of

    NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);

       NVIC Priority groups
    NVIC_InitTypeDef NVIC_InitStructure;

      Structure variable naming
    NVIC_InitStructure.NVIC_IRQChannel=TIM2_IRQn ;

        Timer TIM2 stay NCIV Interrupt channel
    NVIC_InitStructure.NVIC_IRQChannelCmd=ENABLE;

      Channel enable
    NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority=2;

      priority
    NVIC_InitStructure.NVIC_IRQChannelSubPriority=1;

      priority
    NVIC_Init(&NVIC_InitStructure);

    NVIC Initialization function
    TIM_Cmd(TIM2,ENABLE);

    Enable or disable the specified TIM peripherals

 5) Interrupt the call of the service function

void TIM2_IRQHandler();

A complete timer initialization is complete .

Two , Code section

1,Timer.c

#include "stm32f10x.h"                  // Device header


void Timer_Init()
{
	RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2,ENABLE);// Turn on TIM2 The clock , Note that APB1Z Bus 
	
	TIM_InternalClockConfig(TIM2);// After power on, the internal clock is used by default , But for the integrity of the program , Still called this function 
	
	// Initialization of time base unit 
	TIM_TimeBaseInitTypeDef TIM_TimerBaseStructure;
	TIM_TimerBaseStructure.TIM_ClockDivision=TIM_CKD_DIV1;// The clock frequency division , Filtering uses 
	TIM_TimerBaseStructure.TIM_CounterMode=TIM_CounterMode_Up ;// Count up 
	TIM_TimerBaseStructure.TIM_Period=10000-1;//ARR The value of the automatic reloader 
	TIM_TimerBaseStructure.TIM_Prescaler=7200-1;//PSC Value of prescaled frequency 
	// Here can be understood as giving 72MHZ Signal division 7200 Share , Each one is 10000hz, Then use a capacity of 10000 The container of 
	// Go and pack , Each fill is 1S
	TIM_TimerBaseStructure.TIM_RepetitionCounter=0;// Repeat counter , Advanced timer 
	TIM_TimeBaseInit(TIM2,&TIM_TimerBaseStructure);
	// To interrupt 
	TIM_ClearFlag(TIM2,TIM_FLAG_Update);
	TIM_ITConfig(TIM2,TIM_IT_Update,ENABLE);// Update interrupted to NVIC
	//NVIC To configure 
	NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);//NVIC Priority groups 
	NVIC_InitTypeDef NVIC_InitStructure;
	NVIC_InitStructure.NVIC_IRQChannel=TIM2_IRQn ;// Timer TIM2 stay NCIV Interrupt channel 
	NVIC_InitStructure.NVIC_IRQChannelCmd=ENABLE;
	NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority=2;// priority 
	NVIC_InitStructure.NVIC_IRQChannelSubPriority=1;// priority 
	NVIC_Init(&NVIC_InitStructure);
	// Start timer 
	TIM_Cmd(TIM2,ENABLE);
}
// Interrupt service function 
//void TIM2_IRQHandler()
//{
//	if(TIM_GetITStatus(TIM2,TIM_IT_Update)==SET)
//	{
//		TIM_ClearITPendingBit(TIM2,TIM_IT_Update);
//	}
//}

2,oled.c

#include "stm32f10x.h"                  // Device header
void LED_Init()
{
	RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA,ENABLE);
	GPIO_InitTypeDef GPIO_InitStructure;
	GPIO_InitStructure.GPIO_Mode=GPIO_Mode_Out_PP;
	GPIO_InitStructure.GPIO_Pin=GPIO_Pin_1 | GPIO_Pin_2;
	GPIO_InitStructure.GPIO_Speed=GPIO_Speed_50MHz;
	GPIO_Init(GPIOA,&GPIO_InitStructure);
	GPIO_SetBits(GPIOA,GPIO_Pin_1 | GPIO_Pin_2);
}
void LED1_ON()
{
	GPIO_ResetBits(GPIOA,GPIO_Pin_1);
}
void LED1_OFF()
{
	GPIO_SetBits(GPIOA,GPIO_Pin_1);
}
void LED1_Turn()
{
	if(GPIO_ReadOutputDataBit(GPIOA,GPIO_Pin_1)==0)
	{
		GPIO_SetBits(GPIOA,GPIO_Pin_1);
	}
	else 
	{
		GPIO_ResetBits(GPIOA,GPIO_Pin_1);
	}
}
void LED2_Turn()
{
	if(GPIO_ReadOutputDataBit(GPIOA,GPIO_Pin_2)==0)
	{
		GPIO_SetBits(GPIOA,GPIO_Pin_2);
	}
	else 
	{
		GPIO_ResetBits(GPIOA,GPIO_Pin_2);
	}
}
void LED2_ON()
{
	GPIO_ResetBits(GPIOA,GPIO_Pin_2);
}
void LED2_OFF()
{
	GPIO_SetBits(GPIOA,GPIO_Pin_2);
}

3,main.c

#include "stm32f10x.h"                  // Device header
#include "Delay.h"
#include "LED.h"
#include "Key.h"
#include "Buzzer.h"
#include "OLED.h "
#include "Timer.h"

uint16_t Num;

int main()
{
	OLED_Init();
	
   Timer_Init();
	OLED_ShowString(1,1,"Num:");
	
	
	
	while(1)
	{
     
		OLED_ShowNum(1,5,Num,5);
		OLED_ShowNum(2,5,TIM_GetCounter(TIM2),5);
	}
	
}
void TIM2_IRQHandler()
{
	if(TIM_GetITStatus(TIM2,TIM_IT_Update)==SET)
	{
		Num++;
		TIM_ClearITPendingBit(TIM2,TIM_IT_Update);
	}
}

Realization Num Add per second 1, And display on the screen .

3、 ... and , summary

stm32 It took a long time to figure out . Everything is difficult at the beginning , But I didn't know it would be so difficult .