Flash and EEPROM memory were used to address two distinct constraints: narrative storage and persistent game state.

To support a story-driven experience, the project required storing a large amount of dialogue text. The ATmega328P provides only 2 KB of SRAM, which is quickly exhausted by runtime variables and buffers. Early attempts to store dialogue in RAM proved infeasible as additional puzzles were added. To solve this, all dialogue text was moved into flash memory (PROGMEM), which offers 32 KB total (approximately 30 KB usable). This approach comfortably accommodated the full narrative while preserving SRAM for critical state and runtime logic.

Code snippet allocating dialogue text to flash memory — Code snippet that allocates dialogue text to flash memory

Separately, the device needed to retain progress across power cycles for both testing and user convenience. This was achieved using the ATmega328P’s EEPROM, where a single persistent value - the player’s current puzzle index - was stored. The value was updated whenever the player progressed, allowing the game to resume from the correct point on the next power-up.