EEPROM (Electrically Erasable Programmable Read-Only Memory)，电可擦可编程只读存储器--一种掉电后数据不丢失的存储芯片。简而言之就是你想断电后arduino还要保存一些参数，就使用EEPROM吧。在各型号的arduino控制器上的AVR芯片均带有EEPROM，也有外接的EEPROM芯片，常见arduino控制器的EEPROM大小：Arduino UNO、Arduino duemilanove-m328、Zduino m328均使用ATmega328芯片，EEPROM都为1KArduino duemilanove-m168的EEPROM为512bytesArduino 2560的EEPROM为4K下面我们介绍arduino自带的EEPROM使用方法，arduino的库已经为我们准备好了EEPROM类库，我们要使用得先调用EEPROM.h，然后使用write和read方法，即可操作EEPROM。

另：下面的官方例子由于写成较早，所以讲EEPROM的大小都定为了512字节，实际使用中，大家可参照上面所说的EEPROM大小，自行更改。

1.写入

选择 File>Examples>EEPROM>eeprom_write

    /*
    * EEPROM Write
    *
    * Stores values read from analog input 0 into the EEPROM.
    * These values will stay in the EEPROM when the board is
    * turned off and may be retrieved later by another sketch.
    */

    #include <EEPROM.h>

    // EEPROM 的当前地址,即你将要写入的地址,这里就是从0开始写
    int addr = 0;

    void setup()
    {
    }

    void loop()
    {
      //模拟值读出后是一个0-1024的值，但每字节的大小为0-255，所以这里将值除以4再存储到val
      int val = analogRead(0) / 4;
      
      // write the value to the appropriate byte of the EEPROM.
      // these values will remain there when the board is
      // turned off.
      EEPROM.write(addr, val);
      
      // advance to the next address.  there are 512 bytes in
      // the EEPROM, so go back to 0 when we hit 512.
      addr = addr + 1;
      if (addr == 512)
        addr = 0;
      
      delay(100);
    }

2.读取

选择 File>Examples>EEPROM>eeprom_read

    /*
    * EEPROM Read
    *
    * Reads the value of each byte of the EEPROM and prints it
    * to the computer.
    * This example code is in the public domain.
    */

    #include <EEPROM.h>

    // start reading from the first byte (address 0) of the EEPROM
    int address = 0;
    byte value;

    void setup()
    {
      // initialize serial and wait for port to open:
      Serial.begin(9600);
      while (!Serial) {
        ; // wait for serial port to connect. Needed for Leonardo only
      }
    }

    void loop()
    {
      // read a byte from the current address of the EEPROM
      value = EEPROM.read(address);
      
      Serial.print(address);
      Serial.print("\t");
      Serial.print(value, DEC);
      Serial.println();
      
      // advance to the next address of the EEPROM
      address = address + 1;
      
      // there are only 512 bytes of EEPROM, from 0 to 511, so if we're
      // on address 512, wrap around to address 0
      if (address == 512)
        address = 0;
       
      delay(500);
    }

3.清除

选择 File>Examples>EEPROM>eeprom_clear清除EEPROM的内容，其实就是把EEPROM中每一个字节写入0，因为只用清一次零，所以整个程序都在setup部分完成。

    /* * EEPROM Clear
    *
    * Sets all of the bytes of the EEPROM to 0.
    * This example code is in the public domain.

    */
    #include <EEPROM.h>

    void setup()
    {
      // 让EEPROM的512字节内容全部清零
      for (int i = 0; i < 512; i++)
        EEPROM.write(i, 0);
       
      // 清零工作完成后，将L灯点亮，提示EEPROM清零完成
      digitalWrite(13, HIGH);
    }

    void loop()
    {
    }