首页 › Arduino › [已解决]用共用体读写EEPROM乱码

陈野猪 发表于 2014-6-20 09:59:46

[已解决]用共用体读写EEPROM乱码

本帖最后由 陈野猪 于 2014-6-20 22:19 编辑

买了个DUE，但是没有内置的EEPROM，只好用AT24C32，参考坛子里用共用体写了一个读写程序，但是写进去后读出来结果不一样。后来用mega2560测试也不行，各位大大帮我指点一下吧~~
#include <Wire.h> //I2C library

void i2c_eeprom_write_byte( int deviceaddress, unsigned int eeaddress, byte data ) {
    int rdata = data;
    Wire.beginTransmission(deviceaddress);
    Wire.write((int)(eeaddress >> 8)); // MSB
    Wire.write((int)(eeaddress & 0xFF)); // LSB
    Wire.write(rdata);
    Wire.endTransmission();
}

// WARNING: address is a page address, 6-bit end will wrap around
// also, data can be maximum of about 30 bytes, because the Wire library has a buffer of 32 bytes
void i2c_eeprom_write_page( int deviceaddress, unsigned int eeaddresspage, byte* data, byte length ) {
    Wire.beginTransmission(deviceaddress);
    Wire.write((int)(eeaddresspage >> 8)); // MSB
    Wire.write((int)(eeaddresspage & 0xFF)); // LSB
    byte c;
    for ( c = 0; c < length; c++)
      Wire.write(data);
    Wire.endTransmission();
}

byte i2c_eeprom_read_byte( int deviceaddress, unsigned int eeaddress ) {
    byte rdata = 0xFF;
    Wire.beginTransmission(deviceaddress);
    Wire.write((int)(eeaddress >> 8)); // MSB
    Wire.write((int)(eeaddress & 0xFF)); // LSB
    Wire.endTransmission();
    Wire.requestFrom(deviceaddress,1);
    if (Wire.available()) rdata = Wire.read();
    return rdata;
}

// maybe let's not read more than 30 or 32 bytes at a time!
void i2c_eeprom_read_buffer( int deviceaddress, unsigned int eeaddress, byte *buffer, int length ) {
    Wire.beginTransmission(deviceaddress);
    Wire.write((int)(eeaddress >> 8)); // MSB
    Wire.write((int)(eeaddress & 0xFF)); // LSB
    Wire.endTransmission();
    Wire.requestFrom(deviceaddress,length);
    int c = 0;
    for ( c = 0; c < length; c++ )
      if (Wire.available()) buffer = Wire.read();
}
union floatType
{
    float a;
    byte b;
};
floatType num1;
union intType
{
    int a;
    byte b;
};
intType int1;
void setup()
{
    int1.a=0;
    num1.a=987.65;
//    num1.a=781.03;
    int addr=0,i;   
    Wire.begin(); // initialise the connection
    Serial.begin(9600);   
    Serial.println("Write:");
//    for(int i=0;i<2;i++)
//    {
//      byte temp=num1.b;
//      i2c_eeprom_write_byte(0x57, addr++,int1.b);
//    }
   for(int i=0;i<4;i++)
    {
      i2c_eeprom_write_byte(0x57, addr++,num1.b);
    }
    Serial.print('\n');   
}

void loop()
{
    int i,b;
    float num2;
    int int2;
    intType int1;
    floatType temp;
    int addr=0; //first address   
    Serial.println("Read:");
    for(i=0;i<4;i++)
    {   
      temp.b = i2c_eeprom_read_byte(0x57, i); //access an address from the memory
      
    }
    num2=temp.a;
    Serial.println(num2);
   Serial.print('\n');
    delay(2000);
}

陈野猪 发表于 2014-6-20 22:19:25

问题已经解决 在写入时加入延时就可以了

加饭 发表于 2014-8-29 16:31:05

陈野猪 发表于 2014-6-20 22:19 static/image/common/back.gif
问题已经解决 在写入时加入延时就可以了

你好，我copy你的代码，读写都添加延时调试时，串口只循环返回
Read:
nan
何解？

陈野猪 发表于 2014-9-5 16:09:31

加饭 发表于 2014-8-29 16:31 static/image/common/back.gif
你好，我copy你的代码，读写都添加延时调试时，串口只循环返回
Read:
nan


用的什么板子呢？

加饭 发表于 2014-9-10 13:46:00

UNO和mega都试过，结果都一样

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