[已解决]用共用体读写EEPROM乱码

陈野猪

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~~

1. #include <Wire.h> //I2C library
   
2. 
   
3. void i2c_eeprom_write_byte( int deviceaddress, unsigned int eeaddress, byte data ) {
   
4.     int rdata = data;
   
5.     Wire.beginTransmission(deviceaddress);
   
6.     Wire.write((int)(eeaddress >> 8)); // MSB
   
7.     Wire.write((int)(eeaddress & 0xFF)); // LSB
   
8.     Wire.write(rdata);
   
9.     Wire.endTransmission();
   
10.   }
    
11. 
    
12.   // WARNING: address is a page address, 6-bit end will wrap around
    
13.   // also, data can be maximum of about 30 bytes, because the Wire library has a buffer of 32 bytes
    
14.   void i2c_eeprom_write_page( int deviceaddress, unsigned int eeaddresspage, byte* data, byte length ) {
    
15.     Wire.beginTransmission(deviceaddress);
    
16.     Wire.write((int)(eeaddresspage >> 8)); // MSB
    
17.     Wire.write((int)(eeaddresspage & 0xFF)); // LSB
    
18.     byte c;
    
19.     for ( c = 0; c < length; c++)
    
20.       Wire.write(data[c]);
    
21.     Wire.endTransmission();
    
22.   }
    
23. 
    
24.   byte i2c_eeprom_read_byte( int deviceaddress, unsigned int eeaddress ) {
    
25.     byte rdata = 0xFF;
    
26.     Wire.beginTransmission(deviceaddress);
    
27.     Wire.write((int)(eeaddress >> 8)); // MSB
    
28.     Wire.write((int)(eeaddress & 0xFF)); // LSB
    
29.     Wire.endTransmission();
    
30.     Wire.requestFrom(deviceaddress,1);
    
31.     if (Wire.available()) rdata = Wire.read();
    
32.     return rdata;
    
33.   }
    
34. 
    
35.   // maybe let's not read more than 30 or 32 bytes at a time!
    
36.   void i2c_eeprom_read_buffer( int deviceaddress, unsigned int eeaddress, byte *buffer, int length ) {
    
37.     Wire.beginTransmission(deviceaddress);
    
38.     Wire.write((int)(eeaddress >> 8)); // MSB
    
39.     Wire.write((int)(eeaddress & 0xFF)); // LSB
    
40.     Wire.endTransmission();
    
41.     Wire.requestFrom(deviceaddress,length);
    
42.     int c = 0;
    
43.     for ( c = 0; c < length; c++ )
    
44.       if (Wire.available()) buffer[c] = Wire.read();
    
45.   }
    
46.   union floatType
    
47.   {
    
48.     float a;
    
49.     byte b[4];
    
50.   };
    
51.   floatType num1;
    
52.   union intType
    
53.   {
    
54.     int a;
    
55.     byte b[2];
    
56.   };
    
57.   intType int1;
    
58.   void setup()
    
59.   {
    
60.     int1.a=0;
    
61.     num1.a=987.65;
    
62. //    num1.a=781.03;
    
63.     int addr=0,i;   
    
64.     Wire.begin(); // initialise the connection
    
65.     Serial.begin(9600);   
    
66.     Serial.println("Write:");
    
67. //    for(int i=0;i<2;i++)
    
68. //    {
    
69. //      byte temp=num1.b[i];
    
70. //      i2c_eeprom_write_byte(0x57, addr++,int1.b[i]);
    
71. //    }
    
72.      for(int i=0;i<4;i++)
    
73.     {
    
74.       i2c_eeprom_write_byte(0x57, addr++,num1.b[i]);
    
75.     }
    
76.     Serial.print('\n');   
    
77.   }
    
78. 
    
79.   void loop()
    
80.   {
    
81.     int i,b;
    
82.     float num2;
    
83.     int int2;
    
84.     intType int1;
    
85.     floatType temp;
    
86.     int addr=0; //first address   
    
87.     Serial.println("Read:");
    
88.     for(i=0;i<4;i++)
    
89.     {     
    
90.       temp.b[i] = i2c_eeprom_read_byte(0x57, i); //access an address from the memory
    
91.         
    
92.     }
    
93.     num2=temp.a;
    
94.     Serial.println(num2);
    
95.      Serial.print('\n');
    
96.     delay(2000);
    
97.   }

复制代码

陈野猪

问题已经解决 在写入时加入延时就可以了

加饭

陈野猪 发表于 2014-6-20 22:19
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

加饭 发表于 2014-8-29 16:31
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

UNO和mega都试过，结果都一样