Putting a signed integer into external EEPROM

Projects Programming
2

It's that easy, use the Wire.write()s to your EEPROM instead of the EEPROM.write() you see in the playground article. You can eliminate some code if you do a sequential write:

void writeEEPROM(int deviceaddress, unsigned int eeaddress, uint32_t data ) 
{
  Wire.beginTransmission(deviceaddress);
  Wire.write((int)(eeaddress >> 8));   // MSB
  Wire.write((int)(eeaddress & 0xFF)); // LSB
  Wire.write(data & 0xff);
  Wire.write((data >> 8) & 0xff);
  Wire.write((data >> 16) & 0xff);
  Wire.write((data >> 24) & 0xff);
  Wire.endTransmission();
}

or a bit faster:

void writeEEPROM(int deviceaddress, unsigned int eeaddress, uint32_t data ) 
{
  Wire.beginTransmission(deviceaddress);
  Wire.write((int)(eeaddress >> 8));   // MSB
  Wire.write((int)(eeaddress & 0xFF)); // LSB
  uint i;
  for (i = 0; i < 4; i++) {
    Wire.write(data & 0xff);
    data >>= 8;
  }
  Wire.endTransmission();
}