Sega Master System/Technical specifications
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Technical specifications for the Sega Master System.
Contents
CPU
- Main CPU: NEC 780C (based on Zilog Z80)[3]
- Clock rate: 3.579545 MHz (NTSC), 3.54689493 MHz (PAL/SECAM)[n 1]
- The Z80 directly addresses program RAM and ROM, but only addresses VRAM through VDP hardware ports.[1] It can access VRAM by commanding/programming VDP.[4]
- Instruction set: 8‑bit and 16‑bit instructions, 6–18 registers[5]
- Bus width: 8‑bit
- Performance: 0.51 MIPS[5]
Graphics
- GPU: Sega VDP[1][6]
- Revisions: Sega 315‑5124 / Yamaha YM2602 (Mark III, Master System), Sega 315‑5246 / NEC UPD9004G (Master System II)
- Note: An evolution of the TMS9918
- Clock rate: 10.738635 MHz (NTSC),[7] 10.6406848 MHz (PAL)[8]
- Pixel clock rate: 5.3693175 MHz (NTSC), 5.3203424 MHz (PAL)[9]
- Bus width: 16‑bit[n 2]
- Memory bus clock rate: 5.3693175 MHz (NTSC), 5.3203424 MHz (PAL)
- Registers: 8‑bit and 16‑bit[10][4]
- Memory access: VDP directly addresses VRAM, has its own internal CRAM and sprite line buffer, and has access to cartridge ROM. It can be commanded and programmed by Z80.
- Color TV signal encoder: Rohm BA7230LS[3] / Sony V7040 RGB Encoder / Sony CXA1145[11] / Fujitsu MB3514[12] / Sony V7040 / Motorola MC1377[13][14]
- Color burst clock input: 3.579545 MHz (NTSC),[3] 3.546895 MHz (PAL)
- Screen resolutions: 256x192 and 256x224. PAL/SECAM also supports 256x240.
- 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]
- VDP display modes:[4]
- VRAM bandwidth:
- Pixel fillrate:
- 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
- Characters/Tiles: 8x8 pixel characters/tiles, 16 colors per tile, maximum 488 unique characters/tiles on screen (due to VRAM space limitation), horizontal & vertical background tile flipping (up to 1792 flipped tiles in VRAM)
- Background: Tilemap playfield, 8x8 tiles, horizontal & vertical tile flipping, up to 448 tiles/patterns in VRAM used by background,[19] up to 1792 flipped tiles in VRAM used by background, definable priorities for individual background tiles[4]
- Sprites: 16 colors (15 opaque, 1 transparent) per sprite, up to 256 tiles/patterns in VRAM used by sprites,[4] collision detection[20]
- 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[21]
- Sprites per scanline: 8 sprites (non-flickering) per scanline, 9 flickering sprites per scanline[22]
- Scrolling: Smooth hardware scrolling, horizontal & vertical scrolling, diagonal scrolling, line scrolling, partial screen scrolling[23]
- IRQ raster interrupt capabilities:[23] Interrupt per frame, interrupt per scanline,[4] mid‑frame palette swap, transparency effect, line scrolling, partial screen scrolling
- VRAM screen map: 2 KB to 2.25 KB[19]
- 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[24]
Audio
- PSG sound chip: Sega PSG (SN76496) @ 3.579545 MHz[3][25]
- 4 channel mono sound[23]
- 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
- 4 channel mono sound[23]
- FM sound chip: Yamaha YM2413[23]
- 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)[26][3]
- VDP internal memory: 64 bytes (512 bits)[4]
- Color RAM (CRAM): 32 bytes (256 bits, 32x 8-bit entries)
- Sprite line buffer: 32 bytes (256 bits, 8x 32-bit entries)
- System ROM: 8 KB (64 Kbits) to 256 KB (2 Mbits), depending on built‑in game
- Cartridge ROM: 8 KB to 32 KB (Sega Card), 128 KB to 4 MB (Cartridge)[27]
- 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)[28]
Configuration
Bandwidth
Notes
- ↑ [CPU clock cycles per frame: 59,736 (NTSC), 71,364 (PAL)
CPU clock cycles per scanline: 228 CPU clock cycles per frame: 59,736 (NTSC), 71,364 (PAL)
CPU clock cycles per scanline: 228] - ↑ [16‑bit VRAM bus, 8‑bit Z80/ROM bus 16‑bit VRAM bus, 8‑bit Z80/ROM bus]
- ↑ [Byte per 12 cycles[17] Byte per 12 cycles[17]]
- ↑ [16‑bit per tile[23]
- 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)
- 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)]
- ↑ [768 background tiles, 64-256 sprite tiles 768 background tiles, 64-256 sprite tiles]
- ↑ [279/281 ns[29][30] 279/281 ns[29][30]]
- ↑ [260 ns[29][31] 260 ns[29][31]]
- ↑ [279/281 ns 279/281 ns]
- ↑ [2 buses (24-bit bus width) 2 buses (24-bit bus width)]
- ↑ Jump up to: 10.0 10.1 [8-bit bus 8-bit bus]
- ↑ [16-bit bus 16-bit bus]
- ↑ Jump up to: 12.0 12.1 12.2 [8-bit 8-bit]
- ↑ [16-bit 16-bit]
References
- ↑ Jump up to: 1.0 1.1 1.2 1.3 1.4 1.5 File:SMSServiceManualEU.pdf
- ↑ Jump up to: 2.0 2.1 2.2 https://github.com/ekeeke/Genesis-Plus-GX/blob/master/core/system.h
- ↑ Jump up to: 3.0 3.1 3.2 3.3 3.4 Sega Mark-III Hardware Notes (2008-11-14)
- ↑ Jump up to: 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)
- ↑ Jump up to: 5.0 5.1 Obsolete Microprocessors
- ↑ Jump up to: 6.0 6.1 6.2 File:SMS2ServiceManualEU.pdf
- ↑ File:SMSServiceManualEU.pdf, page 4
- ↑ File:SMSServiceManualEU.pdf, page 14
- ↑ https://github.com/mamedev/mame/blob/master/src/mame/drivers/sms.cpp
- ↑ File:SoftwareReferenceManualForSegaMarkIIIEU.pdf
- ↑ File:CXA1145P datasheet.pdf
- ↑ File:MB3514 datasheet.pdf
- ↑ Sega Master System Video Output
- ↑ Jump up to: 14.0 14.1 14.2 Sega Master System Documents
- ↑ Genesis Plus
- ↑ TMS9918 test (AtariAge)
- ↑ File:SC-3000ServiceManual.pdf, page 12
- ↑ Bytes written to VRAM per frame
- ↑ Jump up to: 19.0 19.1 File:SoftwareReferenceManualForSegaMarkIIIEU.pdf, page 8
- ↑ File:SoftwareReferenceManualForSegaMarkIIIEU.pdf, page 6
- ↑ Displaying more than 32 colours - raster effect (SMS Power)
- ↑ Coleco graphics capacity (AtariAge)
- ↑ Jump up to: 23.0 23.1 23.2 23.3 23.4 Sega Master System Technical Documentation (1998-06-10)
- ↑ Fun with zooming (SMS Power)
- ↑ Sega SN76489
- ↑ Jump up to: 26.0 26.1 Sega Master System RAM
- ↑ Jump up to: 27.0 27.1 SMSARCH: A Sega Master System Cartridge Archiver
- ↑ Sega Mappers
- ↑ Jump up to: 29.0 29.1 File:UPD4168 datasheet.pdf
- ↑ File:KM6264B datasheet.pdf
- ↑ File:HM65256B datasheet.pdf
- ↑ File:CXK3864 datasheet.pdf
- ↑ ROM Part Numbers
- ↑ File:MB831000 datasheet.pdf
- ↑ Memory Mapper Hardware Notes
- ↑ SMS PINOUTs: ROMs (Wayback Machine: 2009-02-05 13:19)
- ↑ File:TMS27C512 datasheet.pdf
- ↑ File:AM29F040 datasheet.pdf
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