[SOLVED] how to write and read form eeprom 24c32?

[manoharn]

hai i am doing project using pic18f458 and eeprom 24c02 & i done read write operations correctly but its memory is only 256 bytes , i need memory more than this so i choose eeprom 24c32.

In 24c02 i am writing only "one 8bit" data but in 24c32 i need to write "two 8bit" data,so i need to know how to write two 8 bit data.


ex:for 24c02

let m3=10;//memory location
i2c_eeprom_write(m3,0,dat[0]);

m3=m3+2;

whatever data in the dat[0] its writing to memory location m3 i.e 10 and i don't know o in above i2c_eeprom_write instruction ,in eeprom.c its given like i2c_eeprom_write(unsigned long int addrh,unsigned char addrl,unsigned char data)



any idea for 24c32?

 

[FvM]

What's i2c_eeprom_write()? Apparently you are using a specific compiler with a built-in I2C library but forgot to mention it.

Presumedly the library already handles 24C32 addressing...

 

[manoharn]

thank u......I am using MPLAB IDE & i added eeprom.c library to the project folder and called in the program.IT is correctly working for 24c02 eeprom.

inside that library the functions like this....

---

Code C - [expand]
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void i2c_eeprom_write(unsigned long int addrh,unsigned long int addrl,unsigned long int data)
{
        i2c_start();
        i2c_write(0xA0);                // send chip addr and set data to write mode
        i2c_write(addrh);               // high addr bits
        i2c_write(addrl);               // low addr bits
        i2c_write(data);                // write data
        i2c_stop();
        delay_ms(5);
}
 
/************************** Eeprom Read **************************************/
/**** Reads a single byte from the eeprom supports 2^16 addresses ****/
 
unsigned char i2c_eeprom_read(unsigned long int addrh,unsigned long int addrl)
{
        unsigned char temp;
 
        i2c_start();
 
        i2c_write(0xA0);                // send address data in write mode
        i2c_write(addrh);               // high addr bits
        i2c_write(addrl);               // low addr bits
 
        i2c_start();
        i2c_write(0xA1);                // change to read mode
        temp = i2c_read(0);             // reads are not acknowledged (0)
 
        i2c_stop();                     // if no stop() can get continuous read
 
return temp;
}

---

but i don't know how to write "two 8bit data"...

 

[alexan_e]

By "two 8bit data" you mean the addressing needed by the eeprom or the data you want to store?

The eeprom needs a control byte, word address1 , word address0, data and these are correctly send by the function you have shown so what is the problem?

i2c_write(0xA0); // send chip addr and set data to write mode
i2c_write(addrh); // high addr bits
i2c_write(addrl); // low addr bits
i2c_write(data); // write data

- - - Updated - - -

To write the first position use i2c_eeprom_write(0,0,dat[0]);
for the second i2c_eeprom_write(0,1,dat[0]);
the third i2c_eeprom_write(0,2,dat[0]);

you obviously need to use the data you want to write in place of dat[0]

 

[FvM]

Still much confusion...

MPLAB isn't a compiler. We don't know which C-compiler you are using, what the default long data type is etc.

Referring to your original question

but in 24c32 i need to write "two 8bit" data

I thought you are talking about writing 16-Bit addresses, which is correctly done in the shown code. The function parameter type suggests, that you also want to handle 16-Bit data. This is possibly of course, but no problem related to 24C32.

The present code should be able to read and write 8-Bit data from/to 24C32.

 

[manoharn]

thank u..once i ll check & get u back.....

 

[manoharn]

i am using CCS C Compiler....for eeprom 24c32 i connected 10k pullup resistors to SDA & SCL & wp , a0,a1,a2 connected to gnd...is this connections correct?

 

[alexan_e]

Yes that is correct

 

[FvM]

i am using CCS C Compiler

It's shipped with a drivers\2432.c

 

[manoharn]

hai FvM & alexan_e finally i searched 2432.c library, i am trying to understand that library. once i got result i ll get u back.........