蓝桥杯嵌入式学习总结

重要引脚

GPIO	功能
PA1	TIM2_CH2 / SER(74LS595串行数据输入引脚) / 频率可调脉冲
PA2	TIM2_CH3 / USART2_TX / RCK(74LS595串行存储时钟输入引脚) / 频率可调脉冲
PA3	USART2_RX / SCK(74LS595串行移位时钟输入引脚) / 光敏电阻读入引脚
PA4	ADC1_IN4 / SCL(三轴传感器时钟引脚)
PA5	ADC1_IN5 / SDA(三轴传感器数据引脚) / 4*2按键矩阵
PA6	TIM3_CH1 / 占空比可调脉冲 / 温度传感器
PA7	TIM3_CH2 / 占空比可调脉冲 / 温湿度传感器

PBO ADC1_Channel8
PA0 key1
PA8 key2
PB1 key3
PB2 key4

0.文件配置

例程文件配置过程中要在Library中加入libraries文件

1.LED

void led_init(void)
{
	GPIO_InitTypeDef GPIO_InitStructure;
    /* GPIOD Periph clock enable */
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOC|RCC_APB2Periph_GPIOD, ENABLE);
  
	GPIO_InitStructure.GPIO_Pin = GPIO_Pin_2 ;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;
  GPIO_Init(GPIOD, &GPIO_InitStructure);
	
  /* Configure PD0 and PD2 in output pushpull mode */
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_8 | GPIO_Pin_9| GPIO_Pin_10 | GPIO_Pin_11 | GPIO_Pin_12 | GPIO_Pin_13 | GPIO_Pin_14 | GPIO_Pin_15  ;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;
  GPIO_Init(GPIOC, &GPIO_InitStructure);

}

void led_control(u16 led,u8 state)
{  
	if(state==1)
	{
   GPIO_ResetBits(GPIOC,led<<8);	
   GPIO_SetBits(GPIOD,GPIO_Pin_2);
	 GPIO_ResetBits(GPIOD,GPIO_Pin_2);
	}		
  else
	{
   GPIO_SetBits(GPIOC,led<<8);	
   GPIO_SetBits(GPIOD,GPIO_Pin_2);
	 GPIO_ResetBits(GPIOD,GPIO_Pin_2);

  }
}

令pd2置高(1）后，输入是什么，输出就是什么，把pd2再置低(0)，输入是什么，输出保持不变
起到锁存器的功能，但一般程序里只要是pd2置高就可以了，不需要再置低，即不需要锁存功能

2.Buzzer

当我们stm32复位后，PB4引脚默认是作为JTAG接口的RST引脚，因此我们再使用蜂鸣器之前要先把PB4复用回我们的普通IO口。

因此就要加上这条语句

GPIO_PinRemapConfig(GPIO_Remap_SWJ_NoJTRST,ENABLE);
同时我们还要使能复用IO的时钟

RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO | RCC_APB2Periph_GPIOB,ENABLE);
接下来蜂鸣器的用法就跟我们的普通LED是一样的了。

void buzzer_init(void)
{
	GPIO_InitTypeDef GPIO_InitStructure;
    /* GPIOD Periph clock enable */
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO|RCC_APB2Periph_GPIOB, ENABLE);
  GPIO_PinRemapConfig(GPIO_Remap_SWJ_JTAGDisable,ENABLE);
	
	GPIO_InitStructure.GPIO_Pin = GPIO_Pin_4 ;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;
  GPIO_Init(GPIOB, &GPIO_InitStructure);
	
}

3.AT24c02

I2C代码需要在参考例程里面复制粘贴，需要自己编写的是AT24C02代码

void Write_AT24c02(unsigned char add,unsigned char data1)
{
	I2CStart();
	I2CSendByte(0xa0);
	I2CWaitAck();
	I2CSendByte(add);
	I2CWaitAck();
	I2CSendByte(data1);
	I2CWaitAck();
	I2CStop();
}

unsigned char Read_AT24c02(unsigned char add)
{
  unsigned char temp;
	I2CStart();
	I2CSendByte(0xa0);
	I2CWaitAck();
	I2CSendByte(add);
	I2CWaitAck();
	I2CStart();
	I2CSendByte(0xa1);
	I2CWaitAck();
	temp=I2CReceiveByte();
	I2CWaitAck();
	I2CStop();
	return temp;

}

使用AT24c02写代码时候要延迟5ms

E2PROM一共有256个字节

如果要存储u16位数据，要用2个地址来分来存储。/256储存高八位，%256存储低八位。

利用共同体储存不同数据类型

// 声明共用体eeprom_float
union eeprom_float
{
   float a;  
   u8 b[4];
}float_write,float_read;

// 将共用体中的数据以字节的方式存放到eeprom中
for(i=0;i<sizeof(float);i++)
{
	Write_AT24c02(0x10+i,float_write.b[i]);
	Delay_Ms(5);
}
for(i=0;i<sizeof(float);i++)
{
	float_read.b[i]=Read_AT24c02(0x10+i);
}

// 此时共用体float_read.a就等于float_write.a，而不需要在存放和读取的时候进行数据类型的转换
sprintf(str,"float_read=%f",float_read.a);
LCD_DisplayStringLine(Line0,str);

/*  
不同类型数据 需要根据字节大小 改变数组长度
u8 u16 u32 s16 float double 
1  2   4   2   4     8
字节大小
*/

省赛中会遇到赋初值情况，第一次读取是初值，后面掉电读取是修改值

	if(Read_AT24c02(0x06)!=2&&Read_AT24c02(0xaa)!=15)   //地址和数值都是瞎写的
	{
				Write_AT24c02(0x01,30);				Delay_MS(5);
				Write_AT24c02(0x02,50);				Delay_MS(5);
				Write_AT24c02(0x03,70);				Delay_MS(5);	
		
				Write_AT24c02(0x06,2); //加了这个语句之后，就可以让这个判断只执行一次				
				Delay_MS(5);
				Write_AT24c02(0xaa,15); 			
				Delay_MS(5);
	}

4.串口通信

stm32f10x_stdperiph_lib\STM32F10x_StdPeriph_Lib_V3.5.0\Utilities\STM32_EVAL\STM3210B_EVAL （328行）

STM32F10x_StdPeriph_Lib_V3.5.0\Project\STM32F10x_StdPeriph_Examples\USART\Printf

DMA_Interrupt

DMA_Interrupt\stm32f10x_it.c（中断函数）

void STM_EVAL_COMInit( USART_InitTypeDef* USART_InitStruct)
{
  GPIO_InitTypeDef GPIO_InitStructure;

  /* Enable GPIO clock */
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA| RCC_APB2Periph_AFIO, ENABLE);

  RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART2, ENABLE);

  /* Configure USART Tx as alternate function push-pull */
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_2;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
  GPIO_Init(GPIOA, &GPIO_InitStructure);


  /* Configure USART Rx as input floating */
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_3;
  GPIO_Init(GPIOA, &GPIO_InitStructure);

  /* USART configuration */
  USART_Init(USART2, USART_InitStruct);
    
  /* Enable USART */
  USART_Cmd(USART2, ENABLE);
}

void USART2_Init(void)
{
  USART_InitTypeDef USART_InitStructure;
  NVIC_InitTypeDef NVIC_InitStructure;
  USART_InitStructure.USART_BaudRate = 115200;
  USART_InitStructure.USART_WordLength = USART_WordLength_8b;
  USART_InitStructure.USART_StopBits = USART_StopBits_1;
  USART_InitStructure.USART_Parity = USART_Parity_No;
  USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;
  USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;

  STM_EVAL_COMInit(&USART_InitStructure);


  NVIC_InitStructure.NVIC_IRQChannel = USART2_IRQn;
  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
  NVIC_Init(&NVIC_InitStructure);

  USART_ITConfig(USART2, USART_IT_RXNE, ENABLE); //注意加上最后一句话

}

PS:第一个字符打印不出来

直接修改while的等待条件，while(USART_GetFlagStatus(USART1, USART_FLAG_TXE)==RESET);把TC改为TXE，因为TXE只能硬件清零，在数据写进DR时就置0，数据移出时置1，可以保证数据不会在DR被覆盖；

int fputc(int ch, FILE *f)
{
  /* Place your implementation of fputc here */
  /* e.g. write a character to the USART */
  USART_SendData(USART2, (uint8_t) ch);

  /* Loop until the end of transmission */
  while (USART_GetFlagStatus(USART2, USART_FLAG_TXE) == RESET)
  {}

  return ch;
}

u8 rx_buf[10];
u8 rx_count=0;
void USART2_IRQHandler(void)
{
  if(USART_GetITStatus(USART2, USART_IT_RXNE) != RESET)
  {
    /* Read one byte from the receive data register */
    USART_ClearITPendingBit(USART2, USART_IT_RXNE);
	rx_buf[rx_count++]=USART_ReceiveData(USART2);
  }
}

使用printf注意：1.打开 Use MicroLIB2.#include"stdio.h"

5.LCD

LCD操作常用函数

  STM3210B_LCD_Init(); //初始化LCD相关IO,并对液晶进行初始化

  LCD_Clear(Blue);//清屏操作

  LCD_SetBackColor(Blue);//设置显示文字的背景色

  LCD_SetTextColor(White);//设置字体颜色

  u8 str[20];
  sprintf(str,"helloworld");
  LCD_DisplayStringLine(Line2,str);

  //在第二行输出helloworld
  

  void Display_val(u16 val)
{
    u8 temp[20];
	sprintf(temp,"val:%5d",val);
	LCD_DisplayStringLine(Line1,temp);
}

  Display_val(77);//在第一行输出77

使用sprintf 注意添加#include "stdio.h"

关于LCD与LED冲突问题

方法一：

void LED_control_ALL(u16 flagstatus)
{
	  GPIOC->ODR=flagstatus<<8;
	  GPIO_SetBits(GPIOD,GPIO_Pin_2);
      GPIO_ResetBits(GPIOD,GPIO_Pin_2);

}
//使用这个函数点灯 可以避免LED冲突
//输入LED_control_ALL(0xfe) 点亮第一个灯

方法二：

void LCD_WriteRAM_Prepare(void)
void LCD_WriteRAM(u16 RGB_Code)
void LCD_WriteReg(u8 LCD_Reg, u16 LCD_RegValue)
开头加上 u16 pcout =GPIOC->ODR  
结尾加上 GPIOC->ODR=pcout   
即可

关于LCD长数据对短数据覆盖问题

方法一：在前面空格

方法二：格式化输出，针对数据

	sprintf((char *)str,"%5dHz",5000);
	LCD_DisplayStringLine(Line1,str);
	sprintf((char *)str,"%5dHz",10);
	LCD_DisplayStringLine(Line1,str);
    //如果是%d则会是10HzHz

	sprintf((char *)str,"%-5dHz",10);
	LCD_DisplayStringLine(Line2,str);
    //数据左对齐

    sprintf((char *)str,"%05dHz",10);
	LCD_DisplayStringLine(Line3,str);
    //数据前面补0
    
    //%x输出十六进制  %o输出八进制 %%输出百分号 %s输出字符串 %c输出字符  %.3f输出小数点后三位

关于LCD字符闪烁与高亮

_Bool lcd_flag=0;

  if(lcd_flag==1)
	{
        memset(lcd_buf,0,sizeof(lcd_buf));
        sprintf((char *)lcd_buf,"      %0.2d:%0.2d:%0.2d",Report_HH, Report_MM, Report_SS);
	    LCD_DisplayStringLine(Line5,lcd_buf);
     }
else		
	{
         memset(lcd_buf,0,sizeof(lcd_buf));
         sprintf((char *)lcd_buf,"        :%0.2d:%0.2d",Report_MM, Report_SS);
	     LCD_DisplayStringLine(Line5,lcd_buf);
     }

//实现LCD字符闪烁 lcd_flag是定时器4设置flag 每0.3s翻转一次


        if(time_sel==0)
       {
        LCD_SetTextColor(Red);//设置字符显示颜色
        LCD_DisplayChar(Line4,200,Report_HH/10+'0');                            
	    LCD_DisplayChar(Line4,200-16,Report_HH%10+'0');
		LCD_SetTextColor(White);//显示单个字符的显示函数
       }

//实现字符变红

6.ADC

PB0对应着ADC的Channel_8

STM32F10x_StdPeriph_Examples\ADC\ADC1_DMA

void adc_Init()
{
	GPIO_InitTypeDef GPIO_InitStructure;
	ADC_InitTypeDef ADC_InitStructure;
	
	RCC_APB2PeriphClockCmd(RCC_APB2Periph_ADC1,ENABLE);
	RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB,ENABLE);

	GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0;
	GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AIN;
	GPIO_Init(GPIOB, &GPIO_InitStructure);
	
	ADC_InitStructure.ADC_Mode = ADC_Mode_Independent;  
	ADC_InitStructure.ADC_ScanConvMode = DISABLE;
	ADC_InitStructure.ADC_ContinuousConvMode = DISABLE; 
	ADC_InitStructure.ADC_ExternalTrigConv = ADC_ExternalTrigConv_None;
	ADC_InitStructure.ADC_DataAlign = ADC_DataAlign_Right;
	ADC_InitStructure.ADC_NbrOfChannel = 1;
	ADC_Init(ADC1, &ADC_InitStructure);
    //初始化的时候注意要把ENABLE改为DISABLE

	ADC_RegularChannelConfig(ADC1, ADC_Channel_8, 1, ADC_SampleTime_13Cycles5);    
    //要注意是ADC1和第八通道

	ADC_Cmd(ADC1, ENABLE);   
	ADC_ResetCalibration(ADC1);

	while(ADC_GetResetCalibrationStatus(ADC1));
	ADC_StartCalibration(ADC1);

	while(ADC_GetCalibrationStatus(ADC1));
}

u16 get_adc()
{
	u16 value;
	
	ADC_SoftwareStartConvCmd(ADC1,ENABLE);
	while(!ADC_GetFlagStatus(ADC1,  ADC_FLAG_EOC));
	value = ADC_GetConversionValue(ADC1);
	
	return value;
}

	while(1)
	{
	   adc_value=get_adc();    
       sprintf(str,"adc: %d",(adc_value/(4096/4))); //分档位 0 1 2 3
       LCD_DisplayStringLine(Line2,str);
	   Delay_Ms(100);
	}
//float(adc_value)/4096*3.3 0~3.3V

ADC模块读到的数据是12位的数据，STM32读到的ADC值，是从0到4095。当把ADC引脚接了GND，读到的是0；当把ADC引脚接了VDD，读到的是4095。

tmp=(float)adc_value/4096*3.3

注意事项

关于get_adc()函数，当使用ADC_SoftwareStartConvCmd()使能软件转换之后，需要使用ADC_GetFlagStatus()函数等待转换结束后，再进行ADC_GetConversionValue()输出。

关于adc_init()函数，初始化的时候注意要把ENABLE改为DISABLE，ADC_RegularChannelConfig() 改成第八通道

7.RTC时钟

注意事项

1.RTC配置的时候结合要选择：LSI内部晶振

2.调用配置NVIC函数

3.中断处理函数

需要用到的文件

RTC/LSI_Calib/main.c （178开始

void RTC_Configuration(void)
{
  /* Enable PWR and BKP clocks */
  RCC_APB1PeriphClockCmd(RCC_APB1Periph_PWR | RCC_APB1Periph_BKP, ENABLE);

  /* 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 RTC Clock */
  RCC_RTCCLKCmd(ENABLE);

  /* Wait for RTC registers synchronization */
  RTC_WaitForSynchro();

  /* Wait until last write operation on RTC registers has finished */
  RTC_WaitForLastTask();

  /* Enable the RTC Second */
  RTC_ITConfig(RTC_IT_SEC, ENABLE);

  /* Wait until last write operation on RTC registers has finished */
  RTC_WaitForLastTask();

  /* Set RTC prescaler: set RTC period to 1sec */
  RTC_SetPrescaler(40000);

  /* Wait until last write operation on RTC registers has finished */
  RTC_WaitForLastTask();

  /* To output second signal on Tamper pin, the tamper functionality
       must be disabled (by default this functionality is disabled) */
  BKP_TamperPinCmd(DISABLE);

  /* Enable the RTC Second Output on Tamper Pin */
  // BKP_RTCOutputConfig(BKP_RTCOutputSource_Second);  
  //屏蔽最后一句话，解决白屏问题
  NVIC_Configuration();
}
//最后需要加上NVIC_Configuration

RTC/Calendar/main.c

在Time_Display函数中加入TimeVar=0 和改为0x00015180 会显示出00:00:00

void RTC_IRQHandler(void)
{
  if (RTC_GetITStatus(RTC_IT_SEC) != RESET)
  {
    /* Clear the RTC Second interrupt */
    RTC_ClearITPendingBit(RTC_IT_SEC);


    /* Enable time update */
    TimeDisplay = 1;

    /* Wait until last write operation on RTC registers has finished */
    RTC_WaitForLastTask();
    
  }
}

void NVIC_Configuration(void)
{
  NVIC_InitTypeDef NVIC_InitStructure;

  /* Configure one bit for preemption priority */
  NVIC_PriorityGroupConfig(NVIC_PriorityGroup_1);

  /* Enable the RTC Interrupt */
  NVIC_InitStructure.NVIC_IRQChannel = RTC_IRQn;
  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 1;
  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
  NVIC_Init(&NVIC_InitStructure);
}

void Time_Display(uint32_t TimeVar)
{
	u8 str[20];
  uint32_t THH = 0, TMM = 0, TSS = 0;
  
  /* Reset RTC Counter when Time is 23:59:59 */
  if (RTC_GetCounter() == 0x0001517F) 
  {
     RTC_SetCounter(0x0);
     /* Wait until last write operation on RTC registers has finished */
     RTC_WaitForLastTask();
  }
  
  /* Compute  hours */
  THH = TimeVar / 3600;
  /* Compute minutes */
  TMM = (TimeVar % 3600) / 60;
  /* Compute seconds */
  TSS = (TimeVar % 3600) % 60;

    sprintf(str,"Time: %0.2d:%0.2d:%0.2d", THH, TMM, TSS);
	LCD_DisplayStringLine(Line1,str);
}
//需要自己修改的只有后俩句

void Time_Adjust(u8 HH，u8 MM,u8 SS)
{
  /* Wait until last write operation on RTC registers has finished */
  RTC_WaitForLastTask();
  /* Change the current time */
  RTC_SetCounter(HH*3600+MM*60+SS);
  /* Wait until last write operation on RTC registers has finished */
  RTC_WaitForLastTask();
}

/*
.......
  while (1)
  {
    /* If 1s has been elapsed */
    if (TimeDisplay == 1)
    {
      /* Display current time */
      Time_Display(RTC_GetCounter());
      TimeDisplay = 0;
    }
  }
.......
*/

8.PWM

需要用到文件：以上是常用GPIO

Project\STM32F10x_StdPeriph_Examples\TIM\PWM_Output

PWM输出相同频率，不同占空比

// 设置输出比较寄存器的值，用于改变PWM的占空比。
void TIM_SetCompare1(TIM_TypeDef* TIMx, uint16_t Compare1)

// 用于设置ARR的值，通过设置ARR的值来改变定时器的频率
void TIM_SetAutoreload(TIM_TypeDef* TIMx, uint16_t Autoreload)

ARR的周期值对应 TIM_TimeBaseStructure.TIM_Period 的设置值

PSC的分频值对应 TIM_TimeBaseStructure.TIM_Prescaler 的设置值

void TIM2_PWM_Init(void)
{
	TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;
	TIM_OCInitTypeDef  TIM_OCInitStructure;
	GPIO_InitTypeDef GPIO_InitStructure;
	uint16_t PrescalerValue = 0;
	uint16_t CCR1_Val = 500;
	

	RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);

	RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA | RCC_APB2Periph_AFIO, ENABLE);

	GPIO_InitStructure.GPIO_Pin =  GPIO_Pin_1|GPIO_Pin_2;
	GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
	GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;

	GPIO_Init(GPIOA, &GPIO_InitStructure);
	

	PrescalerValue = (uint16_t) (SystemCoreClock / 1000000) - 1;

	TIM_TimeBaseStructure.TIM_Period = 1000 - 1;
	TIM_TimeBaseStructure.TIM_Prescaler = PrescalerValue;
	TIM_TimeBaseStructure.TIM_ClockDivision = 0;
	TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;

	TIM_TimeBaseInit(TIM2, &TIM_TimeBaseStructure);

	TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;				
	TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;		
	TIM_OCInitStructure.TIM_Pulse = CCR1_Val;							
	TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;			
	TIM_OC2Init(TIM2, &TIM_OCInitStructure);
	TIM_OC2PreloadConfig(TIM2, TIM_OCPreload_Enable);
	

	TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;					
	TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;		
	TIM_OCInitStructure.TIM_Pulse = CCR1_Val;							
	TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;		
	TIM_OC3Init(TIM2, &TIM_OCInitStructure);
	TIM_OC3PreloadConfig(TIM2, TIM_OCPreload_Enable);

	TIM_ARRPreloadConfig(TIM2, ENABLE);


	TIM_Cmd(TIM2, ENABLE);
}

注：ARP及PSC的设置值都是减1的，所以这里要再加上1，才能还原单片机内部的处理值。

PrescalerValue = (uint16_t) (SystemCoreClock / 1000000) -1 理解

现在我们知道定时器时钟的频率是72MHz，SystemCoreClock是72MHz，则PrescalerValue计算出来是71，我们将预分频器设置为71，查看数据手册，如下图，可以知道会对时钟的频率进行72分频，得到的频率是1MHz。然后把TIM_Period 设置为1000-1，即设置ARR（自动重装载寄存器）为999，即定时器计数器从0开始，计数到999，则会自动重新装载，前面我们得到了频率为1MHz，那么定时器每进行一次重转载的周期是1MHz/1000=1kHz，也就是1ms。

while(1)
{
   TIM_SetAutoreload(TIM2,1000-1); //pwm频率为1khz
   TIM_SetCompare2(TIM2,500);      //PA1(TIM2_CH2)占空比为50%
   TIM_SetCompare3(TIM2,100);      //PA2(TIM2_CH3)占空比为10%
}

不同频率，固定占空比

STM32F10x_StdPeriph_Lib_V3.5.0\Project\STM32F10x_StdPeriph_Examples\TIM\OCToggle

__IO uint16_t TIM3_CCR1_Val = 32768;
__IO uint16_t TIM3_CCR2_Val = 16384;
void tim3_pwm_octoggle(void)
{
	GPIO_InitTypeDef GPIO_InitStructure;
	NVIC_InitTypeDef NVIC_InitStructure;
	TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;
  TIM_OCInitTypeDef  TIM_OCInitStructure;
	
	uint16_t PrescalerValue = 0;
	
  RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE);

  RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA | RCC_APB2Periph_GPIOB|
                         RCC_APB2Periph_GPIOC | RCC_APB2Periph_AFIO, ENABLE);
	

  NVIC_InitStructure.NVIC_IRQChannel = TIM3_IRQn;
  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
  NVIC_Init(&NVIC_InitStructure);
	
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6 | GPIO_Pin_7;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
  GPIO_Init(GPIOA, &GPIO_InitStructure);

  /* Compute the prescaler value */
  PrescalerValue = (uint16_t) (SystemCoreClock / 24000000) - 1;

  /* Time base configuration */
  TIM_TimeBaseStructure.TIM_Period = 65535;
  TIM_TimeBaseStructure.TIM_Prescaler = PrescalerValue;
  TIM_TimeBaseStructure.TIM_ClockDivision = 0;
  TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;

  TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure);

  TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_Toggle;
  TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
  TIM_OCInitStructure.TIM_Pulse = TIM3_CCR1_Val;
  TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_Low;
  TIM_OC1Init(TIM3, &TIM_OCInitStructure);

  TIM_OC1PreloadConfig(TIM3, TIM_OCPreload_Disable);
	
  TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
  TIM_OCInitStructure.TIM_Pulse = TIM3_CCR2_Val;
  TIM_OC2Init(TIM3, &TIM_OCInitStructure);

  TIM_OC2PreloadConfig(TIM3, TIM_OCPreload_Disable);

    /* TIM enable counter */
  TIM_Cmd(TIM3, ENABLE);

  /* TIM IT enable */
  TIM_ITConfig(TIM3, TIM_IT_CC1 | TIM_IT_CC2 , ENABLE);

}

**频率和占空比的计算：**占空比很简单，每计数16384翻转一下电平，一个周期就要计数32768次，占空比毫无疑问为50%。对于实际的输出频率而言，定时器的时钟是72MHz，然后经过3分频为24MHz，一个周期计数32768次，则实际频率就是24MHz/32768=732.4Hz

uint16_t TIM3_capture = 0;
void TIM3_IRQHandler(void)
{
  /* TIM3_CH1 toggling with frequency = 183.1 Hz */
  if (TIM_GetITStatus(TIM3, TIM_IT_CC1) != RESET)
  {
    TIM_ClearITPendingBit(TIM3, TIM_IT_CC1 );
    TIM3_capture = TIM_GetCapture1(TIM3);
    TIM_SetCompare1(TIM3, TIM3_capture + TIM3_CCR1_Val );
  }

  /* TIM3_CH2 toggling with frequency = 366.2 Hz */
  if (TIM_GetITStatus(TIM3, TIM_IT_CC2) != RESET)
  {
    TIM_ClearITPendingBit(TIM3, TIM_IT_CC2);
    TIM3_capture = TIM_GetCapture2(TIM3);
    TIM_SetCompare2(TIM3, TIM3_capture + TIM3_CCR2_Val);
  }


}

.......
while(1)
{
TIM3_CCR1_Val =2400 ; //TIM3_CH1频率 50KHz 
//三分频 24Mhz / 2400 =10 000 =10Khz = 0.1us 整个周期是0.2us 所以是50Khz
TIM3_CCR2_Val =4800 ; //TIM3_CH1频率 25KHz
//同理上面
}
.......

可调频率，占空比

前面可调频率，固定占空比的初始化代码一样，主要不同是在中断函数中。通过改变TIMx_CHx_duty来控制占空比，频率通过控制CCR的值

uint16_t TIM2_capture = 0;
_Bool TIM2_CH2_flag=0,TIM2_CH3_flag=0;
float TIM2_CH2_duty=0.3,TIM2_CH3_duty=0.7;
void TIM2_IRQHandler(void)
{

  if (TIM_GetITStatus(TIM2, TIM_IT_CC2) != RESET)
  {
    TIM_ClearITPendingBit(TIM2, TIM_IT_CC2);
    TIM2_capture = TIM_GetCapture2(TIM3);
		if(TIM2_CH2_flag==1)
		{
			TIM2_CH2_flag=0;
      TIM_SetCompare2(TIM2, TIM2_capture +(u16)( TIM2_CH2_duty * TIM2_CCR2_Val));
		}
		else
		{
			TIM2_CH2_flag=1;
			TIM_SetCompare2(TIM2, TIM2_capture +(u16)( TIM2_CCR2_Val*(1-TIM2_CH2_duty)));
    }
  }

  if (TIM_GetITStatus(TIM2, TIM_IT_CC3) != RESET)
  {
    TIM_ClearITPendingBit(TIM2, TIM_IT_CC3);
    TIM2_capture = TIM_GetCapture3(TIM2);
    TIM_SetCompare3(TIM2, TIM2_capture + TIM2_CCR3_Val);
  }
}

PWM捕获占空比和频率

Project\STM32F10x_StdPeriph_Examples\TIM\InputCapture 初始化链接

原理：

首先把捕获的模式设置为上升沿捕获，发生第一次捕获到上升沿的中断，以此中断时刻作为一个起点，得到的计数值清0，此时将捕获模式设置为下降沿捕获，在发生第二次中断的时候，捕获到了下降沿，得到的计数值为TIM3_CH2_ReadValue1就是一个周期中高电平的时间，然后我们在中断中又将捕获的方式设置为上升沿捕获，那么在第三次产生中断的时候，得到的计数值为TIM3_CH2_ReadValue2。所以到此为止，我们知道了一个周期中高电平和整个周期的时间，那么这个PWM方波的频率和占空比就得到了

PWM方波的频率应该为72MHz/TIM3_CH2_ReadValue2

PWM方波的占空比应该为TIM3_CH2_ReadValue1*100/TIM3_CH2_ReadValue2

//乘一百是为了让占空比显示0-100 而不是小数

void TIM3_Input_Mode_Init(void)
{
  GPIO_InitTypeDef GPIO_InitStructure;
  NVIC_InitTypeDef NVIC_InitStructure;
  TIM_ICInitTypeDef  TIM_ICInitStructure;
	
  RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE);
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);

  GPIO_InitStructure.GPIO_Pin =  GPIO_Pin_6|GPIO_Pin_7;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
  GPIO_Init(GPIOA, &GPIO_InitStructure);
	
  NVIC_InitStructure.NVIC_IRQChannel = TIM3_IRQn;
  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;
  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
  NVIC_Init(&NVIC_InitStructure);
	
  TIM_ICInitStructure.TIM_Channel = TIM_Channel_2;                                                                        
  TIM_ICInitStructure.TIM_ICPolarity = TIM_ICPolarity_Rising;
  TIM_ICInitStructure.TIM_ICSelection = TIM_ICSelection_DirectTI;
  TIM_ICInitStructure.TIM_ICPrescaler = TIM_ICPSC_DIV1;
  TIM_ICInitStructure.TIM_ICFilter = 0x0;

  TIM_ICInit(TIM3, &TIM_ICInitStructure);
  
  TIM_ICInitStructure.TIM_Channel = TIM_Channel_1; //容易忘记通道一
  TIM_ICInit(TIM3, &TIM_ICInitStructure);
	
  /* TIM enable counter */
  TIM_Cmd(TIM3, ENABLE);

  /* Enable the CC2 Interrupt Request */
  TIM_ITConfig(TIM3, TIM_IT_CC1|TIM_IT_CC2, ENABLE);
}


__IO uint16_t  TIM3_CH2_ReadValue1 = 0, TIM3_CH2_ReadValue2 = 0;
__IO uint16_t  TIM3_CH2_CaptureNumber = 0;
__IO uint32_t  TIM3_CH2_Freq = 0;

__IO uint16_t  TIM3_CH1_ReadValue1 = 0, TIM3_CH1_ReadValue2 = 0;
__IO uint16_t  TIM3_CH1_CaptureNumber = 0;
__IO uint32_t  TIM3_CH1_Freq = 0;

u8 TIM3_CH1_Duty,TIM3_CH2_Duty;
u8 capture_flag = 1;

void TIM3_IRQHandler(void)
{ 
    if(TIM_GetITStatus(TIM3, TIM_IT_CC2) == SET) 
  {
    /* Clear TIM3 Capture compare interrupt pending bit */
    TIM_ClearITPendingBit(TIM3, TIM_IT_CC2);
	if(capture_flag == 2)
	{
		if(TIM3_CH2_CaptureNumber == 0)
		{
		  TIM_SetCounter(TIM3, 0);
		  TIM_OC2PolarityConfig(TIM3,TIM_ICPolarity_Falling);
		  TIM3_CH2_CaptureNumber = 1;
		}
		else if (TIM3_CH2_CaptureNumber == 1)
		{
			/* Get the Input Capture value */
			TIM3_CH2_ReadValue1 = TIM_GetCounter(TIM3);
			TIM_OC2PolarityConfig(TIM3,TIM_ICPolarity_Rising);
			TIM3_CH2_CaptureNumber = 2;
		}
		else if(TIM3_CH2_CaptureNumber == 2)
		{
		  /* Get the Input Capture value */
		  TIM3_CH2_ReadValue2 = TIM_GetCounter(TIM3); 
		  /* Frequency computation */ 
		  TIM3_CH2_Freq = (uint32_t) SystemCoreClock / TIM3_CH2_ReadValue2;
		  TIM3_CH2_Duty = TIM3_CH2_ReadValue1 * 100 / TIM3_CH2_ReadValue2;
		  TIM3_CH2_CaptureNumber = 0;
		}
	} 
}
	  if(TIM_GetITStatus(TIM3, TIM_IT_CC1) == SET) 
  {
    /* Clear TIM3 Capture compare interrupt pending bit */
    TIM_ClearITPendingBit(TIM3, TIM_IT_CC1);
	if(capture_flag == 1)
	{
		if(TIM3_CH1_CaptureNumber == 0)
		{
			TIM_SetCounter(TIM3, 0);
			TIM_OC1PolarityConfig(TIM3,TIM_ICPolarity_Falling);
			TIM3_CH1_CaptureNumber = 1;
		}
		else if (TIM3_CH1_CaptureNumber == 1)
		{
			 /* Get the Input Capture value */
			TIM3_CH1_ReadValue1 = TIM_GetCounter(TIM3);
			TIM_OC1PolarityConfig(TIM3,TIM_ICPolarity_Rising);
			TIM3_CH1_CaptureNumber = 2;
		}
		else if(TIM3_CH1_CaptureNumber == 2)
		{
		  /* Get the Input Capture value */
		  TIM3_CH1_ReadValue2 = TIM_GetCounter(TIM3); 
		  
		  /* Frequency computation */ 
		  TIM3_CH1_Freq = (uint32_t) SystemCoreClock / TIM3_CH1_ReadValue2;
		  TIM3_CH1_Duty = TIM3_CH1_ReadValue1 * 100 / TIM3_CH1_ReadValue2;
		  TIM3_CH1_CaptureNumber = 0;
		}  
	}
}
}

void TIM4_IRQHandler(void)
{
	static u16 pwm_capture_count=0;;
  if (TIM_GetITStatus(TIM4, TIM_IT_Update) != RESET)
  {
    TIM_ClearITPendingBit(TIM4, TIM_IT_Update);
		pwm_capture_count++;
   if(pwm_capture_count==100)
		{
			pwm_capture_count=0;
			capture_flag = capture_flag % 2 + 1;
			TIM3_CH1_CaptureNumber=0;
			TIM3_CH2_CaptureNumber=0;
		}
  }
}

9.KEY

输出模式是浮空输出

void key_init(void)
{
	GPIO_InitTypeDef GPIO_InitStructure;
    /* GPIOD Periph clock enable */
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA|RCC_APB2Periph_GPIOB, ENABLE);
  
	GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0 | GPIO_Pin_8  ;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
  GPIO_Init(GPIOA, &GPIO_InitStructure);
	
  /* Configure PD0 and PD2 in output pushpull mode */
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_1 | GPIO_Pin_2 ;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING
  GPIO_Init(GPIOB, &GPIO_InitStructure);

}

unsigned char Trg;
unsigned char Cont;
void key_read(void)
{
  unsigned char ReadData = (KEYPORT)^0xff;
  Trg = ReadData & (ReadData ^ Cont);
  Cont = ReadData;
}
/*（1） 没有按键的时候       ReadData ＝ 0    Trg ＝ 0    Cont ＝ 0
  （2） 第一次PB0按下的情况  ReadData ＝ 0x01 Trg ＝ 0x01 Cont ＝ 0x01
  （3） PB0长按             ReadData ＝ 0x01 Trg ＝ 0    Cont ＝ 0x01
  （4） 按键松开的情况       ReadData ＝ 0    Trg ＝ 0    Cont ＝ 0x00
*/

key.h

#ifndef __KEY_H
#define __KEY_H

#include "stm32f10x.h"
void key_init(void);
void key_read(void);

#define KB1 	GPIO_ReadInputDataBit(GPIOA,GPIO_Pin_0)
#define KB2 	GPIO_ReadInputDataBit(GPIOA,GPIO_Pin_8)
#define KB3 	GPIO_ReadInputDataBit(GPIOB,GPIO_Pin_1)
#define KB4 	GPIO_ReadInputDataBit(GPIOB,GPIO_Pin_2)

#define KEYPORT KB1 | (KB2 << 1) | (KB3 << 2) | (KB4 << 3) | 0xf0

extern unsigned char Trg;
extern unsigned char Cont;

#endif

需要自己配置记住三行按键代码需要多练习

关于按键长短按判断

int main(void)
{
 ......//初始化
	while(1)
	{
		if(key_flag)
      {
				key_flag=0;//定时器4 10ms判断一次
				key_read();//三行代码	
				if(Cont == 0x01) //按键按下判断
				{
					key_number++;
					if(key_number>=50&&key_false==1) //50 * 10 ms = 500ms
					{
						key_false=0;
						key_number=0;
						lcd_number+=10;
                     }
                }
				if(Cont ==0x00 && Trg ==0x00) //松手监测
				{
					if(key_number>0 && key_number<50 && key_false==1)
					{
						  lcd_number++;
                    }
                      key_number=0;
				      key_false=1;
                }
	 }
	}
}

10.TIM

在比赛提供的V3.5库的"Project->STM32F10x_StdPeriph_Examples->TIM->TimeBase"文件夹

void tim4_init(void)
{
	TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure; 
  NVIC_InitTypeDef NVIC_InitStructure;
	
  RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM4, ENABLE);

  NVIC_InitStructure.NVIC_IRQChannel = TIM4_IRQn;
  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;
  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
	
  NVIC_Init(&NVIC_InitStructure);
	
  TIM_TimeBaseStructure.TIM_Period =999 ;       
  TIM_TimeBaseStructure.TIM_Prescaler = 71;     //72 000 000 /72 = 1 000 000 
  TIM_TimeBaseStructure.TIM_ClockDivision = 0;
  TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;

  TIM_TimeBaseInit(TIM4, &TIM_TimeBaseStructure);

  TIM_ITConfig(TIM4,TIM_IT_Update, ENABLE);

  TIM_Cmd(TIM4, ENABLE);

}


void TIM4_IRQHandler(void)
{
	static u16 buzzer_count =0;
  if (TIM_GetITStatus(TIM4, TIM_IT_Update) != RESET)
  {
    TIM_ClearITPendingBit(TIM4, TIM_IT_Update);
    buzzer_count++;
		if(buzzer_count==500)
		{
			buzzer_count=0;
			buzzer_flag=1; 
    }
  }
}

中断设置改为TIM_IT_Update
时钟设置为TIM4

使用TIM4原因

TIM2，TIM3做硬件PWM输出和捕获时会用到，TIM1是高级定时器。所以用Tim4

PWM与USART冲突

由于usart接受引脚为PA2，而PWM2的输出引脚也是PA2这就导致了，当我们需要PWM波时需要关闭USART功能，即失能usart的接受中断，开启命令和时钟

#define PWM_ENABLE 	1
#define UART_ENABLE 2
void PWM_UART_Enable(u8 flag)
{
	if(flag==PWM_ENABLE)
	{
		USART_Cmd(USART2, DISABLE);
		RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART2, DISABLE);
		RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);	
		TIM_Cmd(TIM2, ENABLE);
	}
	
	if(flag==UART_ENABLE)
	{
	    TIM_Cmd(TIM2, DISABLE);
		RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, DISABLE);		
		RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART2, ENABLE);
		USART_Cmd(USART2, ENABLE);
	}
}

省赛代码

gitee 代码：https://gitee.com/yin-shijie111/code.git

版权声明：本文为CSDN博主「Yinzz2」的原创文章，遵循CC 4.0 BY-SA版权协议，转载请附上原文出处链接及本声明。
原文链接：https://blog.csdn.net/weixin_51062259/article/details/122521002

蓝桥杯嵌入式学习总结

重要引脚

0.文件配置

例程文件配置过程中要在Library中加入libraries文件

1.LED

2.Buzzer

3.AT24c02

利用共同体储存不同数据类型

省赛中会遇到赋初值情况，第一次读取是初值，后面掉电读取是修改值

4.串口通信

5.LCD

关于LCD与LED冲突问题

方法二：

关于LCD长数据对短数据覆盖问题

关于LCD字符闪烁与高亮

6.ADC

注意事项

7.RTC时钟

注意事项

8.PWM

PWM输出相同频率，不同占空比

不同频率，固定占空比

可调频率，占空比

PWM捕获占空比和频率

9.KEY

key.h

关于按键长短按判断

10.TIM

使用TIM4原因

PWM与USART冲突

省赛代码

一文给你讲清楚 UART ，IIC ，SPI

STA（静态时序分析）详解：如何计算最大时钟频率，以及判断电路是否出现时钟违例（timing violation）?

Yinzz2

暂无评论

发表评论取消回复

单片机教程

DIY

极客&创客

重要引脚

0.文件配置

例程文件配置过程中要在Library中加入libraries文件

1.LED

2.Buzzer

3.AT24c02

利用共同体储存不同数据类型

省赛中会遇到赋初值情况，第一次读取是初值，后面掉电读取是修改值

4.串口通信

5.LCD

关于LCD与LED冲突问题

方法二：

关于LCD长数据对短数据覆盖问题

关于LCD字符闪烁与高亮

6.ADC

注意事项

7.RTC时钟

注意事项

8.PWM

PWM输出相同频率，不同占空比

不同频率，固定占空比

可调频率，占空比

PWM捕获占空比和频率

9.KEY

key.h

关于按键长短按判断

10.TIM

使用TIM4原因

PWM与USART冲突

省赛代码

打赏作者

一文给你讲清楚 UART ，IIC ，SPI

STA（静态时序分析） 详解：如何计算最大时钟频率，以及判断电路是否出现时钟违例（timing violation）?

Yinzz2

暂无评论

发表评论 取消回复

相关推荐

STA（静态时序分析）详解：如何计算最大时钟频率，以及判断电路是否出现时钟违例（timing violation）?

发表评论取消回复