Blue Bridge Cup embedded_ STM32 learning_ Key_ Explain in detail

Code

source ： Blue Bridge Cup Official ;

Configuration code

#include "key.h"
// KEY Interface initialization 
void KEY_Init(void)
{
    
  GPIO_InitTypeDef GPIO_InitStructure;// Set structural variables 
  //  allow GPIOA and GPIOB The clock 
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);// Turn on the clock 
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB, ENABLE);
  // PA0 and PA8 Floating input ( Reset state , It can be omitted )
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0 | GPIO_Pin_8;// Select pin 
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;// Choice mode ,key Recommended pull-up  GPIO_Mode_IPU
  GPIO_Init(GPIOA, &GPIO_InitStructure);// Initialize pins GPIOA
  // PB1 and PB2 Floating input ( Reset state , It can be omitted )
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_1 | GPIO_Pin_2;// Select pin 
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;// Choice mode 
  GPIO_Init(GPIOB, &GPIO_InitStructure);// Initialize pins GPIOB
}
// KEY scanning 
unsigned char KEY_Scan(void)
{
    
  unsigned char ucKey_Val = 0;
  //  Judge B1 and B2 Whether to press  1111 1110 1111 1111
  if(~GPIO_ReadInputData(GPIOA) & 0x101)// Take the opposite first and then ,0000 0001 0000 0001, as long as GPIOA_0 and GPIOA_8 There is a press 
  {
    
    Delay_KEY(10); //  Time delay 10ms Desquamation 
    if(!GPIO_ReadInputDataBit(GPIOA, GPIO_Pin_0))// Determine which press 
      //ucKey_Val = 1;
		return 1;// return 1, And jump out of the function 
    if(!GPIO_ReadInputDataBit(GPIOA, GPIO_Pin_8))
      //ucKey_Val = 2;
		return 2;
	}
  //  Judge B3 and B4 Whether to press 
  else if(~GPIO_ReadInputData(GPIOB) & 6)
  {
    //0000 0000 0000 0110
    Delay_KEY(10);		//  Time delay 10ms Desquamation 
    if(!GPIO_ReadInputDataBit(GPIOB, GPIO_Pin_1))
      ucKey_Val = 3;
    if(!GPIO_ReadInputDataBit(GPIOB, GPIO_Pin_2))
      ucKey_Val = 4;
  }
  return ucKey_Val;
}

void Delay_KEY(unsigned int ms)// Delay chattering 
{
    
  unsigned int i, j;

  for(i=0; i<ms; i++)
    for(j=0; j<7992; j++);			// SYSCLK = 72MHz
// for(j=0; j<1598; j++); // SYSCLK = 8MHz
}

Application code

#include "key.h"
#include "led.h"

unsigned char ucLed = 1;//LED Display parameters 
unsigned char ucKey_Long;// Last key value 
unsigned long ulTick_ms, ulKey_Time;// current time , Last time 

void KEY_Proc(void);// Statement KEY_Proc function 

int main(void)
{
    
  SysTick_Config(72000);			//  timing 1ms(HCLK = 72MHz)
  KEY_Init();// Key initialization 
  LED_Init();//LED initialization 
  BUZ_Init();// Buzzer initialization 

  while(1)
  {
    
    KEY_Proc();
    LED_Disp(ucLed);
  }
}

void KEY_Proc(void)
{
    
  unsigned char ucKey_Val;

  ucKey_Val = KEY_Scan();// Get the key value 
  if(ucKey_Val != ucKey_Long)// When the current key value is not equal to the last key value 
  {
    
    ucKey_Long = ucKey_Val;// Update key value 
    ulKey_Time = ulTick_ms;// Update time 
  }
  else
	  ucKey_Val = 0;// Otherwise, the current key value is cleared 

  if(ucKey_Val == 1)				// B1 Short press 
  {
    
    ucLed <<= 1;// Every time you press , Running water lights up the next light 
    if(ucLed == 0) ucLed = 1;
  }
  if(ucKey_Val == 2)				// B2 Short press 
  {
    
    ucLed >>= 1;
    if(ucLed == 0) ucLed = 0x80;
  }
  if(ucKey_Long == 1)				// B1 Long press 
  {
    
    if(ulTick_ms-ulKey_Time > 800)// When the current time is greater than the last time 800ms when 
    {
    
      ulKey_Time = ulTick_ms;// Update time 
      ucLed <<= 2;
      if(ucLed == 0) ucLed = 1;
    }
  }
  if(ucKey_Long == 2)				// B2 Long press 
  {
    
    if(ulTick_ms-ulKey_Time > 800)
    {
    
// ulKey_Time = ulTick_ms;
      ucLed >>= 2;
      if(ucLed == 0) ucLed = 0x80;
    }
  }
  if(ucKey_Long == 3)				// B3 Long press 
    GPIO_ResetBits(GPIOB, GPIO_Pin_4);// Turn on the buzzer 
  else
    GPIO_SetBits(GPIOB, GPIO_Pin_4);

}
// SysTick Interrupt handling 
void SysTick_Handler(void)
{
    
  ulTick_ms++;// Every time 1ms Current time plus 1
}

Quick configuration

Open the official peripheral routine in the library file , find GPIO——

stay IOToggle" Under the folder , open “main.c”——
Copy and paste the basic configuration directly , Then modify the pin ;

Just recite the rest by yourself hhhh.