Arduino教程（提高篇）——使用EEPROM斷電也能保存資料

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1K Arduino duemilanove-m168的EEPROM为512bytes Arduino 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 ? 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 /*  * 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 ? 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 /*  * 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。 ? 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 /* * 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() { }