/*
   EEPROM Write

   Stores values read from analog input 0 into the EEPROM.
   These values will stay in the EEPROM when the board is
   turned off and may be retrieved later by another sketch.
*/

#include <EEPROM.h>

/** the current address in the EEPROM (i.e. which byte we're going to write to next) **/
int addr = 0;

void setup() {
  /** Empty setup. **/
}

void loop() {
  /***
    Need to divide by 4 because analog inputs range from
    0 to 1023 and each byte of the EEPROM can only hold a
    value from 0 to 255.
  ***/

  int val = analogRead(0) / 4;

  /***
    Write the value to the appropriate byte of the EEPROM.
    these values will remain there when the board is
    turned off.
  ***/

  EEPROM.write(addr, val);

  /***
    Iterate through each byte of the EEPROM storage.

    Larger AVR processors have larger EEPROM sizes, E.g:
    tinyAVR 0/1/2-series 2k flash:      64b
    tinyAVR 0/1/2-series 4-8k flash:    128b
    tinyAVR 0/1/2-series 16-32k flash:  256b
    megaAVR 0-series:                   256b (all flash sizes)
    DA, DB, EA-series:                  512b (all flash sizes)
    DD-series:                          256b (all flash sizes)

    Rather than hard-coding the length, you should use the pre-provided length function.
    This will make your code portable to all AVR processors.
  ***/

  addr = addr + 1;
  if (addr == EEPROM.length()) {
    addr = 0;
  }

  /***
    As the EEPROM sizes are powers of two, wrapping (preventing overflow) of an
    EEPROM address is also doable by a bitwise and of the length - 1.

    ++addr &= EEPROM.length() - 1;
  ***/


  delay(100);
}