In the writeData function you must not use Wire.endTransmission(1);
It must be either Wire.endTransmission(); or Wire.endTransmission(0);
You only use (1) when doing a read - in between writing the address and then issuing the requestFrom.
Pete
Hello Pete.
I've changed the (1) with the () ind the write, but it doesn't make any change. Still wrong data in the EEPROM.
The sketch in now as below :
#include <Wire.h> // for I2C
#define i2caddr 0x50 // device address
byte d=0; // data to store in or read from the EEPROM
void setup()
{
Serial.begin(9600); // Initialize the serial line
Wire.begin(); // wake up the I2C
Serial.println("Writing data...");
for (int i=0; i<257; i++)
{
writeData(i,i);
}
Serial.println("DONE");
Serial.println("Reading data...");
for (int i=0; i<257; i++)
{
Serial.print(i);
Serial.print(" : ");
d=readData(i);
Serial.println(d, DEC);
}
Serial.println("DONE");
}
// writes a byte of data in memory location addr
void writeData(unsigned int addr, byte data)
{
Wire.beginTransmission(i2caddr);
// set the pointer position
//Wire.write((int)(addr >> 8));
Wire.write((int)(addr & 0xFF));
Wire.write(data);
Wire.endTransmission();
delay(10);
}
// reads a byte of data from memory location addr
byte readData(unsigned int addr)
{
byte result;
Wire.beginTransmission(i2caddr);
// set the pointer position
//Wire.write((int)(addr >> 8));
Wire.write((int)(addr & 0xFF));
Wire.endTransmission(1);
Wire.requestFrom(i2caddr,1); // get the byte of data
result = Wire.read();
return result;
}
void loop()
{
}
By the way. I'm having so hard time with this I2C EEPROM, would you have any good link with some sketches very well explained. I haven't been able to find something that could help me properly yet !
At the end, my project is to reprogram a Laser printer chip.
So, read an EEPROM (brand new and already programmed), then, write the data to the old one, so I've got a spare one.
I'll need some advice to do this. I've already read the data of the new 24C04.
I'll now need to inject these data in the old one.
EepromWR2.ods (10.2 KB)
At the end of writeData you have a delay. Try replacing it with this code:
while(1) {
Wire.beginTransmission(i2caddr);
if(Wire.endTransmission() == 0)break;
}
This code waits until the device has finished writing (it won't respond until it is done). But your delay of 20ms should be plenty of time to finish a write. It's worth a try.
I'm using larger EEPROMs (e.g. 24LC1026) but other than that your code is the same as mine.
Pete
Here's my attempt to read/write to a 24LC256 EEPROM using I2C:
Hi.
Sorry for the late response but I was on something else these time.
To make it working, I needed to power up the Arduino through an external 12VDC power supply instead of the USB cable from the computer or even a 5vDC supply through Vin of the ARDUINO.
I also replace the delay by El Supremo's piece of code witch I thing is much more clever than wasting time with Delay and being not sure that the job is done !
But the problem was raelly the power supply of the ARDUINO. At least it now works fine.
Now I'm sure the writing and reading is ok, how can I write the proper number in each piece of memory ?
See, I've read the Eeprom I want to copy so I stored all the data in an open office format as .ods (OoCalc)or .odt (OoWriter) format)
1/ Read the data
2/ Copy from the SerialMonitor
3/ Paste in a calc or writer page to save the data in a safe place.
But I don't know how to program the new Eeprom with these data.
I'm not going to write each data at a time in the serial monitor. here must be a better way for sure.
Any advice.
How I can put these data in ?
I recently intefaced with a similar EEPROM, 24LC01. I used the EEPROM24 library, which is really simple. Strongly reccomended, and support all kinds if 24xCxx EEPROMS