Mega-Pi

Free plan Linux

What Mega-Pi is

Mega-Pi is a free Sega Mega Drive/Genesis emulator designed to run directly on Raspberry Pi 3 or 4 hardware, without an operating system such as Linux. The project says this approach enables near-instant boot and very low input latency. It uses the Picodrive emulation core with the Circle bare-metal C++ framework, assigning orchestration, video, audio and input tasks across four Raspberry Pi ARM cores.

The emulator scans Genesis and Mega Drive games in .bin, .md and .gen formats. It also supports Sega CD/Mega CD games in .cue with .bin tracks and compressed .chd formats, including Sub-CPU, PCM and CD audio, and rotation/scaling graphics hardware emulation. Video uses 2× integer nearest-neighbor scaling to 640×480, while audio is 44.1 kHz stereo through the Pi PWM sound engine. USB gamepads and keyboards are supported; save states go on the SD card, and favorites can be saved in a text file there. Running it requires a FAT32 SD card, boot files, a Raspberry Pi kernel image, game files and USB input devices. Sega CD play also requires regional BIOS files in a bios folder. The project provides a release archive; building it requires the GNU Arm Embedded Toolchain and prior setup of Circle.

Who it suits

Mega-Pi is for Raspberry Pi 3 or 4 owners who want to run Genesis/Mega Drive games directly on the hardware. It also suits users seeking Sega CD support who can supply the required BIOS files and prepare an SD-card installation.

What it does well

Free emulator for Raspberry Pi 3 and 4.
Supports Genesis/Mega Drive and Sega CD/Mega CD formats.
Supports USB gamepads and keyboards.
Stores save states and favorites on the SD card.
Provides 640×480 video and 44.1 kHz stereo audio output.

What to know first

Requires a FAT32 SD card and Raspberry Pi kernel image.
Sega CD play requires regional BIOS files.
Compiling requires the GNU Arm Embedded Toolchain and Circle setup.

Getting started

Get the release archive from the project repository.
Prepare a FAT32 SD card with boot files and a Raspberry Pi 3 or 4 kernel image.
Add game files to a roms folder on the SD card.
Connect a USB gamepad or keyboard.
For Sega CD games, add the appropriately named regional BIOS file or files to a bios folder on the SD card.
To compile instead of using a release, configure and build Circle, then use the GNU Arm Embedded Toolchain.

Verdict

Pick Mega-Pi if you have a Raspberry Pi 3 or 4 and want a bare-metal emulator with Genesis and Sega CD support. Sega CD use requires regional BIOS files, and building from source requires toolchain and framework preparation.

Questions

Does Mega-Pi cost anything?

The project is listed as free.

What hardware does it support?

The build instructions target Raspberry Pi 3 and Raspberry Pi 4.

What game formats can it scan?

It scans .bin, .md and .gen Genesis/Mega Drive files, as well as .cue and .chd Sega CD/Mega CD files.

Does Sega CD support need BIOS files?

Yes. Regional BIOS files named bios_CD_U.bin, bios_CD_E.bin or bios_CD_J.bin are required in a bios folder on the SD card.

Can I use a gamepad?

The emulator supports USB gamepads and USB keyboards.

Can I compile the project?

Compiling requires the GNU Arm Embedded Toolchain, and Circle must be configured and built first.

Facts from Mega-Pi's own pages

BIOS setup: Sega CD support requires regional BIOS files named `bios_CD_U.bin`, `bios_CD_E.bin`, or `bios_CD_J.bin` in a `bios` folder on the SD card. · github.com, 3 Oct 2026
Boot and latency: The project says bypassing an operating system such as Linux enables near-instant boot times and ultra-low input latency. · github.com, 2 Oct 2026
Build requirement: The project’s compile instructions require the GNU Arm Embedded Toolchain (`arm-none-eabi-gcc`). · github.com, 3 Oct 2026
Controls: The emulator supports USB gamepads and USB keyboards out of the box. · github.com, 3 Oct 2026
Credits: The project credits R. Stange for Circle and notaz and community contributors for Picodrive. · github.com, 2 Oct 2026
Display and audio: The video core performs 2× integer nearest-neighbor upscaling to 640×480, and audio is output as 44.1 kHz stereo through the Pi PWM sound engine. · github.com, 3 Oct 2026
Distribution: The repository page lists a mega-pi-release-v1.1.zip file and documents packaging a release archive. · github.com, 2 Oct 2026
Emulation core: It uses the Picodrive emulation core and the Circle bare-metal C++ framework. · github.com, 3 Oct 2026
Favorites: Game favorites are stored persistently in `SD:/roms/favorites.txt`. · github.com, 3 Oct 2026
Installation: Running it requires a FAT32 SD card containing the boot files, the compiled kernel image, a `roms` folder, and—when using Sega CD games—a `bios` folder. · github.com, 3 Oct 2026
Maker: The GitHub profile identifies the repository owner as Alexsander Loula and lists Sao Paulo, Brazil. · github.com, 3 Oct 2026
Multicore design: The emulator distributes orchestration, video, audio, and input work across the Raspberry Pi’s four ARM cores. · github.com, 3 Oct 2026
Purpose: Mega-Pi is a bare-metal Sega Mega Drive/Genesis emulator designed to run on Raspberry Pi. · github.com, 3 Oct 2026
ROM formats: It scans Genesis/Mega Drive `.bin`, `.md`, and `.gen` files, as well as Sega CD `.cue` and `.chd` files. · github.com, 3 Oct 2026
Save states: Save states are stored on the SD card, and the README says save operations check SD-card status and confirm sector programming before returning. · github.com, 3 Oct 2026
Sega CD support: It supports Sega CD/Mega CD images in `.cue` with `.bin` tracks and compressed `.chd` formats. · github.com, 3 Oct 2026
Setup requirements: Running it requires a FAT32 SD card, a Raspberry Pi 3 or 4 kernel image, game files, and USB input devices; Sega CD games also require appropriately named BIOS files. · github.com, 2 Oct 2026
Supported hardware: The build instructions describe Raspberry Pi 3 and Raspberry Pi 4 targets. · github.com, 3 Oct 2026
Video and sound: The README describes 2× integer nearest-neighbor upscaling to 640×480 and 44.1 kHz stereo audio through the Pi PWM sound engine. · github.com, 2 Oct 2026

Where Mega-Pi stands on Freedom251

Sega CD Emulators#17 of 19