Advanced MMU: Memory Bank Controllers (MBCs)

Tue, 05 May 2026 00:00:00 +0000

Introduction

So far, our Game Boy emulator has a basic Memory Management Unit (MMU) that can handle the fixed 64KB memory map. This is sufficient for very small ROMs, but most commercial Game Boy games exceed this limit, often by megabytes. How did the original hardware manage this? Through a clever piece of hardware called a Memory Bank Controller (MBC).

In this chapter, we’ll extend our MMU to support MBCs. This is a critical milestone because it unlocks the ability to load and run a vast majority of Game Boy ROMs. We’ll focus on implementing the MBC1 type, which is one of the most common and fundamental MBCs. By the end of this chapter, your emulator will be able to dynamically switch between different ROM and external RAM banks, allowing it to access much larger cartridge data.

MBC on AI VOID

Advanced MMU: Memory Bank Controllers (MBCs)

Introduction