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Sega Master System/Technical specifications

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Technical specifications for the Sega Master System.

  • Master clock cycles per frame: 896,040 (NTSC), 1,070,460 (PAL)[2]
  • Master clock cycles per scanline: 3420[2]

CPU

Graphics

  • Color burst clock input: 3.579545 MHz (NTSC),[3] 3.546895 MHz (PAL)
  • Screen resolutions: 256x192 and 256x224. PAL/SECAM also supports 256x240.
  • Overscan resolution: 342x262 (NTSC), 342x313 (PAL)[4]
  • Scanlines: 262 (NTSC), 313 (PAL)
  • Refresh rate: 59.922743 Hz (NTSC), 49.701459 Hz (PAL)[15]
  • Maximum frame rate: 59.922743 frames/sec (NTSC), 49.701459 frames/sec (PAL)
  • Colors: Up to 32 simultaneous colors (16 for sprites, 16 for background) available from a palette of 64 colors (6‑bit RGB), 16 colors (4‑bit) per pixel/tile/sprite
  • Programmable capabilities: Mid‑frame palette swap allows up to 64 simultaneous colors, 105 color palette (all on screen) possible with static image,[16] integer sprite zooming[17] (up to 32×32 pixels)[18]
  • VDP display modes:[4]
  • Modes 1–2: 256x192 resolution, tilemap, 2 colors per tile, SG-1000 backwards compatibility
  • Mode 3: 64×48 resolution, bitmap, 16 colors per pixel, SG-1000 backwards compatibility
  • Mode 4: 256x192, 256x224 and 256x240 resolutions, tilemap, 16 colors per tile, used by most Master System games
  • VRAM bandwidth:
  • VDP read bandwidth: 7.692306 MB/s
  • Z80 write bandwidth: 298.295 KB/s (NTSC), 295.574 KB/s (PAL)[n 3]
  • Z80 write during active display: 174.794 KB/s (NTSC), 181.112 KB/s (PAL)[20]
  • Read fillrate: 5.369317 MPixels/s (NTSC), 5.320342 MPixels/s (PAL)
  • Mode 3-4 write fillrate: 4-bit per pixel, 596,590 pixels/s (NTSC), 591,148 pixels/s (PAL)
  • Mode 3-4 write during active display: 349,588 pixels/s (NTSC), 362,224 pixels/s (PAL)
  • Mode 1-2 write fillrate: 1-bit per pixel, 2.386363 MPixels/s (NTSC), 2.364595 MPixels/s (PAL)
  • Mode 1-2 write during active display: 1.398352 MPixels/s (NTSC), 1.448896 MPixels/s (PAL)
  • Tile read fillrate: 83,895 tiles/sec (NTSC), 83,130 tiles/sec (PAL)

Mode 4

  • Sprite pixel sizes: 8x8, 8x16
  • Sprite zoom pixel sizes: 16x16, 16x32
  • Sprite line buffer: VDP contains internal sprite line buffer for 8 sprites per scanline, double buffering, prevents delay while VDP reads VRAM, sprite priority determined by order of sprites in buffer[4]
  • Sprites on screen: 64 sprites on screen, more than 64 sprites with mid-screen raster effects[23]
  • Sprites per scanline: 8 sprites (non-flickering) per scanline, 9 flickering sprites per scanline[24]
  • Sprite attribute table: 256 bytes (2 Kbits), including 64 byte tile/pattern data
  • Background name table: 1.75 KB (14 Kbits) or 2 KB (16 Kbits)[4][n 4]
  • Tile write fillrate: 32 bytes per tile, 9321 tiles/sec (NTSC), 9236 tiles/sec (PAL)
  • Write during active display: 5462 tiles/sec (NTSC), 5659 tiles/sec (PAL)

Modes 1-2

See SG-1000 specifications for more details
  • Tiles: 832-1024 tiles,[n 5] 2 colors per tile, 8 bytes per tile
  • Sprites: 32-64 sprites, 64-256 sprite tiles
  • Sprite pixel sizes: 8x8, 16x16
  • Sprite zoom pixel sizes: 16x16, 32x32
  • Tile write fillrate: 8 bytes per tile, 37,286 tiles/sec (NTSC), 36,946 tiles/sec (PAL)
  • Write during active display: 21,849 tiles/sec (NTSC), 22,639 tiles/sec (PAL)
  • Additional Master System capabilities: Raster effects, programmable full screen zooming[26]

Audio

  • 4 channel mono sound[25]
  • 3 square wave sound generator tone channels: 4–10 octaves, 16 volume levels, 1024 (10‑bit) frequencies, 122 Hz to 125 kHz frequency range
  • 1 noise generator channel: White noise, periodic noise, 16‑bit LSFR, 16‑bit ring buffer, 3 preset frequencies (7.8 to 19.5 kHz), can match frequency of 3rd tone channel
  • PCM/PWM sampling: Uses 3 tone channels, 1‑bit to 8‑bit audio depth, 5–64 kHz sampling rate, up to 16 KB per sample
  • Based on TI SN76489
  • 9 mono FM synthesis channels
  • 2‑operator FM synthesis sound
  • Instruments: 15 pre‑defined instruments and user‑defined sound
  • Rhythm mode: 3 channels can be used for percussion sounds
  • Built into Japanese Master System
  • Available as plug‑in module for Mark III
  • Supported by certain games only

Memory

  • System RAM: 24 KB (most models) or 40 KB (some models)[28][3]
  • Main/Program RAM: 8 KB (64 Kbits)
  • Note: Since Z80 reads program code directly from ROM, program RAM is primarily used for general program data (such as state information).[29]
  • VRAM: 16 KB (128 Kbits, most models) or 32 KB (256 Kbits, some models)[14]
  • Color RAM (CRAM): 32 bytes (256 bits, 32x 8-bit entries)
  • Sprite line buffer: 32 bytes (256 bits, 8x 32-bit entries)
  • Note: Z80 can read program code directly from ROM, allowing program RAM to be used for general program data (such as state information).
  • Cartridge battery backup SRAM: 8 KB (64 Kbits) to 32 KB (256 Kbits)[30]

Configuration

  • Z80, VDP <‑> Main RAM, System ROM, Cartridge ROM (8‑bit)
  • VDP <‑> VRAM (16‑bit)
  • Main RAM: 8‑bit, XRAM/SRAM, 3.579545 MHz (NTSC) or 3.546894 MHz (PAL)[n 6]
  • VRAM: 16‑bit (2x 8‑bit), XRAM/PSRAM, 3.846153 MHz[n 7]
  • ROM chips: 8‑bit, 3.579545 MHz (NTSC) or 3.546894 MHz (PAL)[n 8]

Bandwidth

  • System RAM bandwidth: 11 MB/s[n 9]
  • Main RAM: 3.579545 MB/s (NTSC), 3.546894 MB/s (PAL)[n 10]
  • VRAM: 7.692306 MB/s[n 11]
  • ROM bandwidth: 3.5 MB/s[n 10]
  • Internal processor bandwidth:
  • Z80: 3.579545 MB/s (NTSC), 3.546894 MB/s (PAL)[n 12]
  • VDP: 10 MB/s[n 13]
  • CRAM: 5.3693175 MB/s (NTSC), 5.3203424 MB/s (PAL)[n 12]
  • Sprite line buffer: 5.3693175 MB/s (NTSC), 5.3203424 MB/s (PAL)[n 12]

Notes

  1. CPU clock cycles per frame: 59,736 (NTSC), 71,364 (PAL)
    CPU clock cycles per scanline: 228
  2. 16‑bit VRAM bus, 8‑bit Z80/ROM bus
  3. Byte per 12 cyclesMedia:SC-3000ServiceManual.pdf[19]
  4. 16‑bit per tile[25]
    • 256x192 resolution: 1.75 KB, 32x28 table (256x224 pixels), 896 tiles (768 visible)
    • 256x224 resolution: 2 KB, 32x32 table (256x256 pixels), 1024 tiles (896 visible)
    • 256x240 resolution: 2 KB, 32x32 table (256x256 pixels), 1024 tiles (960 visible)
  5. 768 background tiles, 64-256 sprite tiles
  6. 279/281 ns[31][32]
  7. 260 ns[31][33]
  8. 279/281 ns
  9. 2 buses (24-bit bus width)
  10. 10.0 10.1 8-bit bus
  11. 16-bit bus
  12. 12.0 12.1 12.2 8-bit
  13. 16-bit

References

  1. 1.0 1.1 1.2 1.3 1.4 1.5 File:SMSServiceManualEU.pdf
  2. 2.0 2.1 2.2 https://github.com/ekeeke/Genesis-Plus-GX/blob/master/core/system.h
  3. 3.0 3.1 3.2 3.3 3.4 Sega Mark-III Hardware Notes (2008-11-14)
  4. 4.00 4.01 4.02 4.03 4.04 4.05 4.06 4.07 4.08 4.09 4.10 Sega Master System VDP documentation (2002-11-12)
  5. 5.0 5.1 Obsolete Microprocessors
  6. 6.0 6.1 6.2 File:SMS2ServiceManualEU.pdf
  7. File:SMSServiceManualEU.pdf, page 4
  8. File:SMSServiceManualEU.pdf, page 14
  9. https://github.com/mamedev/mame/blob/master/src/mame/drivers/sms.cpp
  10. File:SoftwareReferenceManualForSegaMarkIIIEU.pdf
  11. File:CXA1145P datasheet.pdf
  12. File:MB3514 datasheet.pdf
  13. Sega Master System Video Output
  14. 14.0 14.1 14.2 Sega Master System Documents
  15. Genesis Plus
  16. TMS9918 test (AtariAge)
  17. Sega Master System VDP Documentation
  18. New sprite record (MSX Research Center)
  19. File:SC-3000ServiceManual.pdf, page 12
  20. Bytes written to VRAM per frame
  21. 21.0 21.1 File:SoftwareReferenceManualForSegaMarkIIIEU.pdf, page 8
  22. File:SoftwareReferenceManualForSegaMarkIIIEU.pdf, page 6
  23. Displaying more than 32 colours - raster effect (SMS Power)
  24. Coleco graphics capacity (AtariAge)
  25. 25.0 25.1 25.2 25.3 25.4 Sega Master System Technical Documentation (1998-06-10)
  26. Fun with zooming (SMS Power)
  27. Sega SN76489
  28. 28.0 28.1 Sega Master System RAM
  29. 29.0 29.1 SMSARCH: A Sega Master System Cartridge Archiver
  30. Sega Mappers
  31. 31.0 31.1 File:UPD4168 datasheet.pdf
  32. File:KM6264B datasheet.pdf
  33. File:HM65256B datasheet.pdf
  34. File:CXK3864 datasheet.pdf
  35. ROM Part Numbers
  36. File:MB831000 datasheet.pdf
  37. Memory Mapper Hardware Notes
  38. SMS PINOUTs
  39. File:TMS27C512 datasheet.pdf
  40. File:AM29F040 datasheet.pdf
Sega Master System
 Overview   Sega Master System | Technical Specifications | History
 Hardware Variations   Asia | North America | Europe (West | North | South | Central and East) | South America

Sega Mark III | Sega Game Box 9 | Tectoy Master System Girl | Tectoy Master System Super Compact | Kiosk | Sega System E

Add-ons   Demo Unit II | Telecon Pack | FM Sound Unit | 3-D Glasses
Game Controllers   SJ-152 | Control Pad | 3-D Glasses | Control Stick | Handle Controller | Light Phaser | Paddle Control | Rapid Fire Unit | Sports Pad | SG Commander
Misc. Hardware   Action Replay | Card Catcher | Action Case | Freedom Connection | Playkit
Unreleased Accessories   Floppy Disk Drive
Consoles on a Chip   Arcade Gamer Portable | Coby TF-DVD560 | DVD Karaoke Game DVT-G100 | Fun Play 20-in-1 | Master System 3 | Master System Evolution | Master System Handy | PlayPal Plug & Play | Poga