Arduino 中 EEprom 写入读取清除
转自:https://www.arduino.cn/thread-1157-1-1.html
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
/*
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* EEPROM Write
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*
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* Stores values read from analog input 0 into the EEPROM.
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* These values will stay in the EEPROM when the board is
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* turned off and may be retrieved later by another sketch.
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*/
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// EEPROM 的当前地址,即你将要写入的地址,这里就是从0开始写
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int addr = 0;
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void setup()
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{
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}
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void loop()
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{
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//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
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int val = analogRead(0) / 4;
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// write the value to the appropriate byte of the EEPROM.
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// these values will remain there when the board is
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// turned off.
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EEPROM.write(addr, val);
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// advance to the next address. there are 512 bytes in
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// the EEPROM, so go back to 0 when we hit 512.
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addr = addr + 1;
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if (addr == 512)
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addr = 0;
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delay(100);
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}
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2.读取 选择 File>Examples>EEPROM>eeprom_read
/*
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* EEPROM Read
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*
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* Reads the value of each byte of the EEPROM and prints it
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* to the computer.
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* This example code is in the public domain.
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*/
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// start reading from the first byte (address 0) of the EEPROM
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int address = 0;
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byte value;
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void setup()
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{
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// initialize serial and wait for port to open:
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Serial.begin(9600);
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while (!Serial) {
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; // wait for serial port to connect. Needed for Leonardo only
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}
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}
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void loop()
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{
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// read a byte from the current address of the EEPROM
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value = EEPROM.read(address);
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Serial.print(address);
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Serial.print("\t");
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Serial.print(value, DEC);
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Serial.println();
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// advance to the next address of the EEPROM
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address = address + 1;
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// there are only 512 bytes of EEPROM, from 0 to 511, so if we're
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// on address 512, wrap around to address 0
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if (address == 512)
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address = 0;
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delay(500);
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}
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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
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*
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* Sets all of the bytes of the EEPROM to 0.
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* This example code is in the public domain.
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*/
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void setup()
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{
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// 让EEPROM的512字节内容全部清零
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for (int i = 0; i < 512; i++)
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EEPROM.write(i, 0);
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// 清零工作完成后,将L灯点亮,提示EEPROM清零完成
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digitalWrite(13, HIGH);
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}
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void loop()
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{
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}
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