Master System

Overview

The Sega Master System launched in 1985/1986 as an 8-bit challenger to the NES. Built around a 4 MHz Zilog Z80A CPU with 8 KB of RAM and 16 KB of video RAM, it found its strongest markets in Europe, Brazil, South Korea and Australia. REG-Linux treats the platform as the mastersystem system group so metadata scraping, themes and visual sets stay in sync with its Sega siblings.

Technical specifications

• CPU: Zilog Z80A at 4 MHz (compatible with Game Gear/ZX Spectrum hardware)
• Memory: 8 KB RAM + 16 KB VRAM (TMS9918A-derived tile engine)
• Display: 256×192 resolution, 32 colors per tile, 64 sprites and hardware scrolling
• Sound: Texas Instruments SN76489 PSG (three tone channels plus noise)

Supported ROM extensions

bin, sms, zip, 7z

Quick reference

• ROM folder: /userdata/roms/mastersystem
• Accepted ROM formats: .bin, .sms, .zip, .7z
• Emulators: RetroArch (libretro: GenesisPlusGX, libretro: Picodrive), CLK
• System group: mastersystem

BIOS

No BIOS archive is required for Master System emulation.

ROMs

Place every Master System ROM in /userdata/roms/mastersystem. The same cores also run Game Gear and Mega Drive/Genesis titles, so you can keep the Sega hierarchy tidy inside the roms/ tree if you prefer.

Emulators

RetroArch

RetroArch serves the Sega 8-bit cores. Open the Quick Menu with [HOTKEY] + the south face button (see controller configuration) to adjust shaders, controllers and overrides.

Standardized options: mastersystem.videomode, mastersystem.ratio, mastersystem.smooth, mastersystem.shaders, mastersystem.pixel_perfect, mastersystem.decoration, mastersystem.game_translation, mastersystem.audio_latency, mastersystem.video_threaded.

ES setting name	REG-Linux.conf_key	Description & values
GRAPHICS BACKEND	mastersystem.gfxbackend	Choose OpenGL (opengl) or Vulkan (vulkan).
AUDIO LATENCY	mastersystem.audio_latency	Buffer size in milliseconds: 256, 192, 128, 64, 32, 16, 8. Increase if you hear pops.
THREADED VIDEO	mastersystem.video_threaded	Offload video rendering to another thread (true On, false Off).

libretro: GenesisPlusGX

GenesisPlusGX covers Master System, Game Gear, SG-1000 and more. Additional Master System–specific controls include mastersystem.gpgx_blargg_filter_ms, mastersystem.ym2413, mastersystem.gun_cursor_ms, mastersystem.controller1_ms and mastersystem.controller2_ms.

libretro: Picodrive

Picodrive is a lightweight alternative with similar Sega 8-bit settings referenced in megadrive.md.

CLK (Clock Signal)

CLK arrived in REG-Linux v42+. It offers a low-latency, accurate Banana-style emulation path for the Master System alongside other retro platforms.

Controls

Master System controllers included the two-button gamepad, Light Phaser, paddle and sports pad. The REG-Linux Retropad overlay matches the standard pad layout; use RetroArch's Input menu or the controller configuration tool for special peripherals.

Troubleshooting

When a title misbehaves, consult the generic support pages and consider switching between GenesisPlusGX and Picodrive to see which core handles the ROM best.