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Arduino 驱动8位数码管模块

之前我们使用数码管都是直接使用【参考1】，缺点是电路复杂，占用引脚太多，稍微有点问题就会出现缺笔画的问题（测试的时候务必完整测试，否则很可能遇到你想显示8，结果出现6的状况）。最近入手了下面这个模块，上面通过74HC595芯片驱动LCD，接线很简单。我做了简单的实验，感觉挺方便的。

示例代码

    unsigned char LED_0F[] = 
    {// 0	 1	  2	   3	4	 5	  6	   7	8	 9	  A	   b	C    d	  E    F    -
    	0xC0,0xF9,0xA4,0xB0,0x99,0x92,0x82,0xF8,0x80,0x90,0x8C,0xBF,0xC6,0xA1,0x86,0xFF,0xbf
    };
    unsigned char LED[8];	//用于LED的8位显示缓存
    int SCLK = 10;
    int RCLK = 9;
    int DIO = 8; //这里定义了那三个脚
    
    void setup ()
    {
      pinMode(SCLK,OUTPUT);
      pinMode(RCLK,OUTPUT);
      pinMode(DIO,OUTPUT); //让三个脚都是输出状态
    }
    void loop()
    {
        LED[0]=1;
    	LED[1]=2;
    	LED[2]=3;
    	LED[3]=4;
        LED[4]=5;
    	LED[5]=6;
    	LED[6]=7;
    	LED[7]=8;
    	while(1)
    	{
    		LED8_Display ();
    	} 
      
    }
    
    void LED8_Display (void)
    {
    	unsigned char *led_table;          // 查表指针
    	unsigned char i;
    	//显示第1位
    	led_table = LED_0F + LED[0];
    	i = *led_table;
    	LED_OUT(i);			
    	LED_OUT(0x01);		
        digitalWrite(RCLK,LOW);
        digitalWrite(RCLK,HIGH);
    	//显示第2位
    	led_table = LED_0F + LED[1];
    	i = *led_table;
    	LED_OUT(i);		
    	LED_OUT(0x02);		
        digitalWrite(RCLK,LOW);
        digitalWrite(RCLK,HIGH);
    	//显示第3位
    	led_table = LED_0F + LED[2];
    	i = *led_table;
    	LED_OUT(i);			
    	LED_OUT(0x04);	
        digitalWrite(RCLK,LOW);
        digitalWrite(RCLK,HIGH);
    	//显示第4位
    	led_table = LED_0F + LED[3];
    	i = *led_table;
    	LED_OUT(i);			
    	LED_OUT(0x08);		
        digitalWrite(RCLK,LOW);
        digitalWrite(RCLK,HIGH);

    	//显示第5位
    	led_table = LED_0F + LED[4];
    	i = *led_table;
    	LED_OUT(i);			
    	LED_OUT(0x10);		
        digitalWrite(RCLK,LOW);
        digitalWrite(RCLK,HIGH);
    	//显示第6位
    	led_table = LED_0F + LED[5];
    	i = *led_table;
    	LED_OUT(i);			
    	LED_OUT(0x20);		
        digitalWrite(RCLK,LOW);
        digitalWrite(RCLK,HIGH);
    	//显示第7位
    	led_table = LED_0F + LED[6];
    	i = *led_table;
    	LED_OUT(i);			
    	LED_OUT(0x40);		
        digitalWrite(RCLK,LOW);
        digitalWrite(RCLK,HIGH);        
    	//显示第8位
    	led_table = LED_0F + LED[7];
    	i = *led_table;
    	LED_OUT(i);			
    	LED_OUT(0x80);		
        digitalWrite(RCLK,LOW);
        digitalWrite(RCLK,HIGH);        
    }
    
    void LED_OUT(unsigned char X)
    {
    	unsigned char i;
    	for(i=8;i>=1;i--)
    	{
    		if (X&0x80) 
                {
                  digitalWrite(DIO,HIGH);
                 }  
                else 
                {
                  digitalWrite(DIO,LOW);
                }
    		X<<=1;
                digitalWrite(SCLK,LOW);
                digitalWrite(SCLK,HIGH);
    	}
    }

卖家没有提供相应的代码，上述代码是我根据从其他地方找到的4位LED的代码基础上修改出来的。

工作照片：

附件是卖家提供的8 LED的资料和其他地方找到的 4 LED 的资料。

4LED

8LEDDS

参考：

1. http://www.lab-z.com/4digitial/ Arduino 四位数码管实验
2. http://www.lab-z.com/usb7seg/ USB 控制七段数码管
3. http://www.lab-z.com/usb-%E6%8E%A7%E5%88%B6%E4%B8%83%E6%AE%B5%E6%95%B0%E7%A0%81%E7%AE%A1ii/ USB 控制七段数码管(II)

之前我尝试用 Fritzing 绘制短路图一段时间。这个软件有直观方便的特点。问题是大多数我用到的原件他的库中没有，如果自己绘制的话非常复杂，修改元件管脚也异常麻烦。

http://sourceforge.net/projects/tinycad/

用这个很容易就绘制一个 Arduino Pro Micro的电路

对应文件可以在这里下载
Arduino-Pro-Micro

之前，我们介绍过如何用Arduino Uno打造一个PPT遥控器【参考1】，缺点是制作过程复杂，用到的器件较多导致整体稳定性不好。这里介绍使用 Arduino Pro Micro来做一个同样的PPT遥控器。

原理上和之前的并没有多少差别，都是通过模拟USB键盘的方式来进行控制。差别在于Pro Micro是缩小版的 Leonardo ,内部集成了USB Slave控制器，我们不需要再花费精力模拟自己为USB Keyboard.
硬件连接示意图：

代码是直接修改自示例“KeyboardMessage”

/* 
 Keyboard Button test
 
 For the Arduino Leonardo and Micro.
 
 Sends a text string when a button is pressed.
 
 The circuit:
 * pushbutton attached from pin 2 to +5V
 * 10-kilohm resistor attached from pin 4 to ground
 
 created 24 Oct 2011
 modified 27 Mar 2012
 by Tom Igoe
 
 This example code is in the public domain.
 
 http://www.arduino.cc/en/Tutorial/KeyboardButton
 */

const int buttonPinA = A1;          // input pin for A
const int buttonPinB = A2;          // input pin for B
int previousButtonStateA = HIGH;   // for checking the state of a pushButton
int previousButtonStateB = HIGH;   // for checking the state of a pushButton

void setup() {
  // make the pushButtonA pin an input:
  pinMode(buttonPinA, INPUT);
  // make the pushButtonB pin an input:
  pinMode(buttonPinB, INPUT);
  // initialize control over the keyboard:
  Keyboard.begin();
  delay(10000);
}

void loop() {
  // read the pushbutton:
  int buttonStateA = digitalRead(buttonPinA);
  int buttonStateB = digitalRead(buttonPinB);  
  // if the button state has changed, 
  if ((buttonStateA != previousButtonStateA) 
    // and it's currently pressed:
  && (buttonStateA == HIGH)) {
    // type out a message
    //Keyboard.print("A");
    Keyboard.press(KEY_LEFT_ARROW);
    Keyboard.releaseAll();
  }
  // if the button state has changed, 
  if ((buttonStateB != previousButtonStateB) 
    // and it's currently pressed:
  && (buttonStateB == HIGH)) {
    // type out a message
    //Keyboard.print("B");
    Keyboard.press(KEY_RIGHT_ARROW);
    Keyboard.releaseAll();
  }  
  // save the current button state for comparison next time:
  previousButtonStateA = buttonStateA; 
  previousButtonStateB = buttonStateB;   
}

实物图

工作的视频

http://www.tudou.com/listplay/mAjgE5Ac_Sg/Fz0piTvQ9Cs.html?resourceId=414535982_06_02_99

参考：

1. http://www.lab-z.com/%E7%94%A8-arduino-%E6%89%93%E9%80%A0ppt%E9%81%A5%E6%8E%A7%E5%99%A8/ 用 Arduino 打造PPT遥控器
2. http://arduino.cc/en/Reference/KeyboardModifiers 键值定义