Storing MAC Address in EEPROM via Serial ASCII input.

Projects Programming
4

if you can initialize the ethernetshield with the mac address you can just use those numbers to write too eeprom.

Here a simple function that converts 2 chars to one byte so it needs only one eeprom location. ( It is not the most efficient but it works.)

char ar[] = "0123456789ABCDEF";

byte ascii2byte(char a, char b)
{
   byte v = 0;
   for(uint8_t i=0; i < 16; i++) 
   { 
     if (ar[i] == a) v += (i * 16);
     if (ar[i] == b) v += i;
   }
   return v;
}

HEX is just a representation of a byte/int/long, just like BIN or DEC is. The value itself does not change

BOoting: some pseudocode how I would do it, to get the idea.

in setup() 
{
   x = readEeprom(0);
   if (x == 1) MAC = readMAcFromEEPROM();
}

void loop()
{
   ...
   if (IhaveAMACaddress) 
   {
      writeMacToEEPROM(byteArray);
      writeEEPROM(0, 1);
   }
  ...
}