實(shí)現(xiàn)的任務(wù)就是用LCD做一個(gè)菜單，用按鍵控制不同的LED流轉(zhuǎn)模式。

第一步--熟悉硬件

這個(gè)就是普通的按鍵連接方式，沒(méi)有硬件上消抖所以，就得軟件處理了。經(jīng)過(guò)查閱原理圖發(fā)現(xiàn)，按鍵連接的引腳是PA0，PA8，PB1，PB2。其中PA0有喚醒的功能，不知道會(huì)不會(huì)考。

第二步--軟件設(shè)計(jì)

LED，LCD相關(guān)的東西我在上一篇以及做了，在這里就不說(shuō)了。

那么就是介紹按鍵輸入相關(guān)。

首先就是對(duì)按鍵的初始化

void Key_GPIO_Config(void)
{
  GPIO_InitTypeDef  GPIO_Strue;
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);
  GPIO_Strue.GPIO_Pin = GPIO_Pin_0| GPIO_Pin_8;
  GPIO_Strue.GPIO_Mode = GPIO_Mode_IPU;
  GPIO_Strue.GPIO_Speed =GPIO_Speed_50MHz;
  GPIO_Init(GPIOA, &GPIO_Strue);

  RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB, ENABLE);
  GPIO_Strue.GPIO_Pin = GPIO_Pin_1| GPIO_Pin_2;
  GPIO_Init(GPIOB, &GPIO_Strue);
}

之后就是對(duì)按鍵處理。

因?yàn)橛卸秳?dòng)所以就要消抖。有的教程是延時(shí)消抖，但是延時(shí)的過(guò)程中CPU就是空閑下來(lái)了，無(wú)法對(duì)外界消息做出回應(yīng)，在對(duì)時(shí)間要求較高的場(chǎng)和中就不太適用。既然我是要學(xué)習(xí)的，就要和實(shí)際看齊，就要想一種不太占用CPU的方法。這是定時(shí)器就出來(lái)了，我們將一大段的延時(shí)拆成一小段一小段的，這樣不就減輕CPU的壓力了？

在處理抖動(dòng)的問(wèn)題上，我們可以采用一種濾波的方式，每隔一段時(shí)間采一下值，然后判斷這些值，如果這些值穩(wěn)定在一個(gè)值，那么就說(shuō)明按鍵處于按下或者彈起的狀態(tài)。下面的程序就是實(shí)現(xiàn)這種消抖的方式

void KEY_Scan(void)
{
  uint8_t i;
  uint8_t key_buff[] ={0xff,0xff,0xff,0xff};

  key_buff[0]= (key_buff[0] < < 1) | KEY1;
  key_buff[1]= (key_buff[1] < < 1) | KEY2;
  key_buff[2]= (key_buff[2] < < 1) | KEY3;
  key_buff[3]= (key_buff[3] < < 1) | KEY4;
  for(i = 0; i < 4; i ++)
  {
    if((key_buff[i] & 0x0f) == 0x0f)
    {
      keySta[i] = 1;
    }
    else if((key_buff[i] & 0x0f) == 0x00)
    {
      keySta[i] = 0;
    }
    else{}
  }
}

要實(shí)現(xiàn)每隔一段時(shí)間就進(jìn)行一次掃描就需要用定時(shí)器掃描，將定時(shí)器配置成1ms進(jìn)一次中斷，然后在中斷里進(jìn)行一次掃描。

那么接下來(lái)就是配置定時(shí)器，這里選擇定時(shí)器4。

void TIM4_Config()
{
  TIM_TimeBaseInitTypeDef TIM_structure;
  NVIC_InitTypeDef NVIC_structure;

  RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM4, ENABLE);
  TIM_structure.TIM_ClockDivision = TIM_CKD_DIV1;
  TIM_structure.TIM_CounterMode = TIM_CounterMode_Up; //計(jì)數(shù)模式 向上計(jì)數(shù)
  TIM_structure.TIM_RepetitionCounter = 0;//設(shè)置重復(fù)計(jì)數(shù)值
  //設(shè)置1ms進(jìn)入一次中斷，，TIM4在APB1時(shí)鐘線上36MHz,那就36預(yù)分頻
  //但是根據(jù)說(shuō)明，如果APB1的預(yù)分頻系數(shù)=1；則頻率不變，否則x2
  //例程的預(yù)分頻x2需要按照72M配置
  TIM_structure.TIM_Prescaler = 72 -1;  //就是1m 它的倒數(shù)就是時(shí)間
  TIM_structure.TIM_Period = 1000-1; //這就是1ms
  TIM_TimeBaseInit(TIM4, &TIM_structure);
  TIM_ClearFlag(TIM4, TIM_FLAG_Update);
  TIM_ITConfig(TIM4, TIM_IT_Update, ENABLE);
  TIM_Cmd(TIM4, ENABLE);  
  //中斷配置；
  NVIC_structure.NVIC_IRQChannel = TIM4_IRQn;
  NVIC_structure.NVIC_IRQChannelPreemptionPriority = 0;
  NVIC_structure.NVIC_IRQChannelSubPriority = 2;
  NVIC_structure.NVIC_IRQChannelCmd = ENABLE;
  NVIC_Init(&NVIC_structure);
}

再寫(xiě)一下中斷程序就差不多了

void TIM4_IRQHandler()
{
  if(TIM_GetITStatus(TIM4, TIM_IT_Update) != RESET)
  {
    KEY_Scan();
    TIM_ClearITPendingBit(TIM4, TIM_IT_Update);
  }
}

之后就是主程序

先來(lái)一個(gè)開(kāi)機(jī)選擇界面

LCD_Clear(Black);
  LCD_SetBackColor(Blue2);
  LCD_SetTextColor(Black);
  LCD_DisplayStringLine(Line0, (uint8_t *)"     LED Control    ");
  LCD_SetBackColor(Black);
  LCD_SetTextColor(White);
  LCD_DisplayStringLine(Line1, (uint8_t *)"        .__        ");
  LCD_DisplayStringLine(Line2, (uint8_t *)"   _____|__|__  ___");
  LCD_DisplayStringLine(Line3, (uint8_t *)"  /  ___/    /  /");
  LCD_DisplayStringLine(Line4, (uint8_t *)"  ___ |  | >    < ");
  LCD_DisplayStringLine(Line5, (uint8_t *)" /____  >__/__/_ ");
  LCD_DisplayStringLine(Line6, (uint8_t *)"      /         /");
  LCD_DisplayStringLine(Line7, (uint8_t *)"________________________");
  LCD_DisplayStringLine(Line8, (uint8_t *)"Press B1 to start...");

然后就是控制界面

LCD_Clear(Black);
      LCD_SetBackColor(Blue);
      LCD_SetTextColor(Black);
      LCD_DisplayStringLine(Line0, (uint8_t *)"   Mode Selection    ");
      LCD_SetBackColor(Black);
      LCD_SetTextColor(White);
      LCD_DisplayStringLine(Line2, (uint8_t *)"       Mode1");
      LCD_DisplayStringLine(Line3, (uint8_t *)"       Mode2");
      LCD_DisplayStringLine(Line4, (uint8_t *)"       Mode3");
      LCD_DisplayStringLine(Line5, (uint8_t *)"       Mode4");
      LCD_DisplayStringLine(Line7, (uint8_t *)"_____________________");
      LCD_DisplayStringLine(Line8, (uint8_t *)"Runing:");
      LCD_DisplayStringLine(Line9, (uint8_t *)"Nothing.");

最后就是一堆邏輯，感覺(jué)寫(xiě)的復(fù)雜了

int main(void)
{
  uint8_t keyval;
  uint8_t mode;
  SysTick_Config(SystemCoreClock/1000);
  NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);//搶占和響應(yīng)優(yōu)先級(jí)的范圍0~3
  STM3210B_LCD_Init();
  LED_Enable_gpio_cofig();
  Key_GPIO_Config();
  TIM4_Config();


  while(1)
  {
    if(start_flag)
    {
      LCD_Clear(Black); 
      while(start_flag)
      {
        count_flag = 0;
        led_count = 0;
        LED_ENABLE();
        GPIO_Write(GPIOC, 0xff00);
        LED_DISENABLE();
        keyval = Get_KeyVal();
        if(keyval == 0xa1)
        {
          start_flag = 0;
        }
      }
    }
    else
    {
      mode = 1;
      while(start_flag == 0)
      {
        keyval = Get_KeyVal();
        if(keyval == 0xa3)
        {
          mode = mode + 1;
          if(mode > 4)
          {
            mode = 4;
          }
        }
        if(keyval == 0xa2)
        {
          mode = mode - 1;
          if(mode <= 1)
          {
            mode = 1;
          }          
        }
        switch(mode)
        {
          case 1:  LCD_DisplayChar(Line2, 16* 14, ' >');
               LCD_DisplayChar(Line3, 16* 14, ' ');
               LCD_DisplayChar(Line4, 16* 14, ' ');
               LCD_DisplayChar(Line5, 16* 14, ' ');
               break;
          case 2:  LCD_DisplayChar(Line2, 16* 14, ' ');
               LCD_DisplayChar(Line3, 16* 14, ' >');
               LCD_DisplayChar(Line4, 16* 14, ' ');
               LCD_DisplayChar(Line5, 16* 14, ' ');
               break;
          case 3:  LCD_DisplayChar(Line2, 16* 14, ' ');
               LCD_DisplayChar(Line3, 16* 14, ' ');
               LCD_DisplayChar(Line4, 16* 14, ' >');
               LCD_DisplayChar(Line5, 16* 14, ' ');
               break;
          case 4:  LCD_DisplayChar(Line2, 16* 14, ' ');
               LCD_DisplayChar(Line3, 16* 14, ' ');
               LCD_DisplayChar(Line4, 16* 14, ' ');
               LCD_DisplayChar(Line5, 16* 14, ' >');
               break;               
        }
        if(keyval == 0xa4)
        {
          count_flag = 1;  
          LCD_ClearLine(Line9);
          switch(mode)
          {
            case 1:  LCD_DisplayStringLine(Line9, (uint8_t *)"Mode1");break;
            case 2:  LCD_DisplayStringLine(Line9, (uint8_t *)"Mode2");break;
            case 3:  LCD_DisplayStringLine(Line9, (uint8_t *)"Mode3");break;
            case 4:  LCD_DisplayStringLine(Line9, (uint8_t *)"Mode4");break;       
          }
        }
        if(keyval == 0xa1)
        {
          start_flag = 1;
        }
        while(count_flag)
        {
          LED_ENABLE();
          GPIO_Write(GPIOC, led_buff[mode-1][led_count]);
          keyval = Get_KeyVal();
          if(keyval == 0xa4)
          {
            count_flag = 0;
            GPIO_Write(GPIOC, 0xff00);
            LED_DISENABLE();  
            LCD_ClearLine(Line9);
            LCD_DisplayStringLine(Line9, (uint8_t *)"Nothing.");
          }
          if(keyval == 0xa1)
          {
            start_flag = 1;
            count_flag = 0;
            GPIO_Write(GPIOC, 0xff00);
            LED_DISENABLE();  
          }          
        } 
      }
    }
  }
}