SNES Cartridge Components

Understanding what’s inside your SNES® cartridges helps with troubleshooting and appreciating how these classic games work.

Opening a cartridge

To inspect the internal components, you’ll need:

• 3.8mm security bit for SNES/Super Famicom® games

Remove the screws on the back and carefully separate the shell halves.

The game chip

The game chip stores the game code, graphics, and audio data. SNES game sizes ranged from 2 Megabits (256 KB) to 48 Megabits (6 MB) for the largest titles like Tales of Phantasia and Star Ocean.

• Official games: Game data is read-only and cannot be modified
• Counterfeit games: Often use rewritable memory
• Flashcarts: Designed for loading different games

Memory mapping

SNES cartridges use different memory mapping schemes to organize how the console accesses game data:

• LoROM: Uses 32 KB banks. Common in smaller games.
• HiROM: Uses 64 KB banks. Common in larger games.
• ExLoROM/ExHiROM: Extended mappings for games larger than 32 Megabits.

The SN Operator automatically detects and handles these mapping types.

Save memory (SRAM)

Unlike Game Boy® games which evolved to use various save technologies, virtually all SNES games with save functionality use SRAM (Static RAM). This battery-backed memory requires constant power to retain data.

SRAM chips are typically 8 KB, though some games use larger sizes. When the battery dies, your save data is lost.

The battery

Cartridges with save functionality use CR2032 coin cell batteries. These power the SRAM while the console is off.

Original batteries typically last 20-30 years, but many are now failing. Back up your saves with the SN Operator before the battery dies!

Enhancement chips

Some SNES games include coprocessor chips that dramatically expand the console’s capabilities:

Super FX (GSU)

A 16-bit RISC processor designed by Argonaut Software for 3D polygon rendering and advanced 2D effects.

SA-1

A faster version of the SNES’s own CPU, running at 10.74 MHz (4x the base speed). Used in 34 games including Kirby Super Star and Super Mario RPG.

DSP (Digital Signal Processor)

Handles complex mathematical calculations. Four versions exist with different microcode:

Other enhancement chips

MAD-1 decoder

Many cartridges include a MAD-1 chip that handles address decoding between the game chip and save memory, simplifying the PCB design.

Identifying components

Chip part numbers are printed on the components themselves. You can search for datasheets online using these numbers to learn more about specific chips.