Predefined int matrix to update via serial from Processing

Thanks. I got your point and updated the code to change the data type to byte.

OK. So, there are three parts to your problem.

  1. Reading the data from the serial port.
  2. Storing the data in EEPROM.
  3. Retrieving the data from EEPROM.

Having changed the data type, the last two will be much easier.

Which part(s) do you need help with?