Sega Saturn/Technical Specifications

This page details the hardware specs of the Sega Saturn video game console.

	+ **2x CPU cores**: 32‑bit RISC instructions/registers, 74.454536 MIPS (37.227268 MIPS each, 1.3 MIPS per MHz), up to 4 instructions/cycle (2 instructions/cycle per SH-2)
	+ **2x DMA units**: 2x DMAC (Direct Memory Access Controller), parallel processing
	+ **4x internal fixed‑point math processors**: 2x MULT multiplier DSP, 2x DIVU division units, parallel processing
		- **2x MULT multiplier DSP**: 57.27272 MOPS fixed-point math (28.63636 MOPS per SH-2)
		- **2x DIVU division units**: 16/32/64-bit division, 1,468,531 divides/sec
	+ **Bus width**: 64‑bit (2× 32‑bit) internal, 32‑bit external
	+ **Word length**: 32-bit

* **System coprocesor**: Custom Saturn Control Unit (SCU), with DSP for geometry processing and DMA controller for system control
	+ **System control processor**: 32‑bit fixed‑point registers/instructions, interrupt controller, DMA controller, 3 DMA channels
	+ **Math coprocessor**: Geometry DSP @ 14.31818 MHz, 32‑bit fixed‑point instructions, 6 parallel instructions per cycle, 85.90908 MIPS (6 MIPS per MHz)

* **CD‑ROM CPU**: Hitachi SH-1 32‑bit RISC processor @ 20 MHz (20 MIPS) (controlling the CD‑ROM)
	+ Contains internal DAC and internal math processor
	+ **Bus width**: 32‑bit internal, 16‑bit external

* **Microcontroller**: Hitachi HD404920[38] (4‑bit MCU) "System Manager & Peripheral Control" (SMPC) @ 4 MHz
	+ **RTC**: 1 MHz (real‑time clock)
	+ **Instruction set**: 4‑bit instructions, 890 ns per instruction, 1.123595 MIPS
	+ **Bus width**: 10‑bit internal, 8‑bit external

* **Optional MPEG Video CD Card**:
	+ **MPEG Video decoder**: Sega P/N 315-5765 (Hitachi HD814101FE)
	+ **MPEG Audio decoder**: Hitachi HD814102F

* **Sound processor**: Yamaha SCSP (Saturn Custom Sound Processor) YMF292
	+ **Sound DSP**: Yamaha FH1 DSP (Digital Signal Processor) @ 22.58 MHz (24‑bit, 128‑step, 4 parallel instructions)
	+ **Bus width**: 24‑bit internal, 16‑bit external

* **Sound CPU**: Motorola 68EC000 (16/32‑bit CISC) sound processor @ 11.29 MHz (1.97575 MIPS)
	+ **Bus width**: 16‑bit internal, 16‑bit external

**Video Processors**:

* **Sega/Hitachi VDP1 @ 28.63636 MHz**: Handles sprite/texture and polygon drawing
	+ **Bus width**: 48‑bit (3x 16‑bit)
	+ **Word length**: 16-bit
* **Sega/Yamaha VDP2 @ 28.63636 MHz**: Backgrounds, scrolling, handles background, scroll and 3D rotation planes
	+ **Bus width**: 32‑bit
	+ **Word length**: 32-bit
* **Sony CXA1645M RGB‑Composite Video Encoder**

### Graphics

* **Graphics pipeline**:
	+ **3 DSP geometry processors**: 2× SH-2 DSP, SCU DSP
	+ **2 VDP rendering processors**: VDP1 for sprites/textures/polygons, VDP2 for planes/backgrounds/textures

* **Video clock rate**: 28.63636 MHz MHz (NTSC), 28.4375 MHz (PAL)
	+ **NTSC dot clock**: 7.15909 MHz (lo-res), 14.31818 MHz (hi-res)
	+ **PAL dot clock**: 7.109375 MHz (lo-res), 14.21875 MHz (hi-res)

* **Display resolutions**: 320×224 to 704×480
	+ **NTSC overscan resolution**: 453×263 (lo-res), 907×263 (hi-res)
	+ **PAL overscan resolution**: 454×313 (lo-res), 908×313 (hi-res)

* **Refresh rate**: 30–60 Hz (NTSC), 25–50 Hz (PAL)
	+ **Maximum frame rate**: 60 FPS (NTSC), 50 FPS (PAL)

* **Color depth**: 15-bit RGB to 32‑bit RGBA (24‑bit color with 8‑bit alpha transparency)
	+ **Color palette**: 16,777,216 (VDP2), 32,768 (VDP1)
	+ **Colors on screen**: 256 to 16,777,216 (VDP2), 256 to 32,768 (VDP1)
	+ **VDP2 colors per background**: 16 colors (4-bit) to 16,777,216 colors (24-bit)
	+ **VDP1 colors per sprite/polygon**: 16 colors (4-bit) to 32,768 colors (15-bit)
	+ **CLUT**: Virtually unlimited number of CLUTs

* **DSP geometry processing**: 188 MIPS (million instructions per second)
	+ **Fixed-point operations**: 114 MOPS (million operations per second)
	+ **Additions**: 85 million adds/sec
	+ **Multiplications**: 85 million multiplies/sec
	+ **16-bit divisions**: 5 million divides/sec

* **Geometry calculations**: 114 MOPS fixed-point calculations
	+ **Vertex transformations**: 2,400,000 vertices/sec
	+ **Polygon transformations**: 1,800,000 polygons/sec
	+ **T&L flat lighting**: 800,000 polygons/sec
	+ **T&L Gouraud lighting**: 700,000 polygons/sec

* **Transmission bus bandwidth**: 143 MB/s
	+ **DSP–VDP transmission bus**: 114.54544 MB/s
	+ **VDP1–VDP2 transmission bus**: 28.63636 MB/s

* **Fillrate**:
	+ **Bitmap/Framebuffer fillrate**: 26–28 MPixels/s (24-bit color), 82–85 MPixels/s (15-bit color), 143–150 MPixels/s (8-bit color), 250–264 MPixels/s (4-bit color)
	+ **Tile fillrate**: 280–570 MPixels/s

* **Optional MPEG Video CD Card**: 704×480 resolution, 30 frames/sec, 16‑bit audio with 44.1 kHz sampling, up to 72 minutes on one CD

**SCU DSP**

* **SCU math coprocessor**: Geometry DSP @ 14.31818 MHz, 32‑bit fixed‑point instructions
	+ **Parallel units**: 32/48-bit ALU (arithmetic logic unit), 48/64‑bit Multiplier, 32-bit instruction decoder
* **Buses**:
	+ **Internal**: 4 parallel buses, 32-bit per bus, 128-bit overall bus width, 3 buses at 14.31818 MHz, 1 bus at 28.63636 MHz
	+ **External**: 32-bit, 28.63636 MHz
* **Cache RAM**: 2 KB (1 KB data, 1 KB program)
* **Instructions**: 6 parallel instructions/cycle (one instruction per unit/bus), 85.90908 MIPS (6 MIPS/MHz)
	+ **Fixed-point operations**: 28.63636 MOPS (million operations per second), 2 MOPS/MHz (2 parallel operations/cycle)
* **Capabilities**: Matrix and vector calculations, 3D point transformations, lighting calculations, fixed-point calculations, faster than SH-2, can use DMA to directly fetch and store vertex data, floating-point operations, geometry transformations, voxel rendering acceleration, fast coordinate transformations, lighting computations, transparency calculations
* **Notes**: Can only be programmed with assembly language, more difficult to program than SH-2

**VDP1**

* **VDP1 @ 28.63636 MHz**: Handles sprite/texture and polygon drawing, color calculation and shading, geometry
	+ **Versions**: Sega 315‑5883 (Hitachi HD64440) Video Display Processor 1 (VDP1), Sega 315‑5689 VDP1
	+ **Adjustable video clock rate**: 28.63636 MHz or 26.8465875 MHz (NTSC), 28.4375 MHz or 26.8426 MHz (PAL)
	+ **Parallel data bus structure**: 3 parallel data buses (dual framebuffers, texture cache), 48-bit data bus width (16-bit per bus), 171.8184 MB/s bandwidth
	+ **Parallel data bus cycles**: 85.90908 million bus cycles/sec
* **Color palette**: 32,768 colors (15-bit RGB) to 16,777,216 (24-bit VDP2 CRAM palette, accessible by VDP1)
	+ **Colors on screen**: 32,768 colors (15-bit RGB) to 1,048,576 colors (15-bit RGB, 32 transparency levels using VDP2 palette)
	+ **Colors per pixel**: 32,768 colors (16bpp, 15-bit RGB), 256 colors (8bpp, 8-bit palette)
* **Features**: Alpha blending, clipping, luminance, shadows, transparency (3 alpha levels, or 32 alpha levels using VDP2 palette), per-pixel transparency
	+ **Polygon capabilities**: Texture mapping, lighting, shading, wire‑frame, flat shading, Gouraud shading, 15-bit color Gouraud shading, 15-bit colored lighting, quad polygons, edge anti‑aliasing, forward texture mapping (form of perspective correction), bilinear approximation (reduces texture warping), medium polygon accuracy (seamless polygons)
* **Framebuffer capabilities**: Double buffering, dual 256 KB framebuffers, rotation & scaling, VDP1 framebuffer can be rotated as bitmap layer by VDP2
	+ **Framebuffer resolution**: 512×256, 512×512, 1024×256
	+ **Overscan resolution**: 1708×263 (NTSC), 1820×313 (PAL), 852×525 (31KC), 848×562 (HDTV)
* **Sprite/Texture capabilities**: Rotation & scaling, flipping, distortion, warping, vertical and horizontal line scrolling, virtually unlimited color lookup tables, System 24/32 sprite rendering system
	+ **Sprite/Texture size**: 8×1 to 504×255 texels
	+ **Colors per sprite/texture in Lo-Res**: 16, 64, 128, 256, and 32,768
	+ **Colors per sprite/texture in Hi-Res**: 16, 64, 128, and 256
	+ **Maximum texels per scanline**: 1812 (NTSC), 1820 (PAL)
	+ **Maximum sprites/textures per scanline**: 226 (NTSC), 227 (PAL)
* **Texture cache VRAM**: 512 KB
	+ **Sprite/Polygon size**: 32 bytes (flat shading), 40 bytes (Gouraud shading), 64–96 bytes (shadows), 72–104 bytes (shadows, Gouraud shading)
	+ **Texture size**: 4 bytes (8×1 texels, 16 colors) to 251.02 KB (504×255 texels, 32,758 colors)
	+ **Maximum sprites per frame**: 16,383 (virtually unlimited), 13,106 (Gouraud shading), 5461–8191 (shadows)
	+ **Maximum polygons per frame**: 16,384 (flat shading), 16,383 (texture mapping), 13,107 (Gouraud shading), 13,106 (texture mapping, Gouraud shading), 8192 (shadows), 8191 (texture mapping, shadows), 7281 (texture mapping, shadows, Gouraud shading)
* **Framebuffer fillrate**: 28.63636 MPixels/s (16bpp), 35.6465 MPixels/s (8bpp)
	+ **Gouraud shading**: 28 MPixels/s (512×512 polygons), 16 MPixels/s (10×10 polygons)
	+ **Shadows/Translucency**: 28 MPixels/s (VDP2 palette), 5 MPixels/s (RGB)
* **Texture fillrate**: 19 MTexels/s (504×255 textures), 14 MTexels/s (10×10 textures), 12 MTexels/s (8×8 textures)
	+ **Gouraud shading**: 19 MTexels/s (504×255 textures), 9 MTexels/s (10×10 textures)
* **Polygon rendering performance**: Lighting
	+ **800,000 polygons/s**: Flat shading, 32-pixel polygons
	+ **500,000 polygons/s**: Flat shading, 50-pixel polygons
	+ **200,000 polygons/s**: Gouraud shading, 32-pixel polygons
* **Texture mapping performance**: Lighting
	+ **300,000 polygons/s**: 32-texel textures
	+ **200,000 polygons/s**: 70-texel textures
	+ **140,000 polygons/s**: Gouraud shading, 32-texel textures

**VDP2**

* **VDP2 @ 57.27272 MHz**: Handles background, scroll and 3D rotation planes
	+ **Versions**: Sega 315‑5890 (Yamaha) Video Display Processor 2 (VDP2), Yamaha 315‑5690 VDP2
	+ **Video clock rate**: 26.8426–28.63636 MHz (NTSC), 26.6564–28.4375 MHz (PAL)
	+ **Memory clock rate**: 53.6852–57.27272 MHz (NTSC), 53.3128–56.875 MHz (PAL)
* **VDP2 cores**: 4 parallel cores (17 units), 28.63636 MHz per core
	+ Bus control
	+ H/V counter & timing generator
	+ **Scroll picture block**: 8 units (Normal picture coordinate calculation, Rotation picture coordinate calculation, Pattern name control, Window control, Character control, Line picture control, VRAM control, Dot data control)
	+ **Video process**: 7 units (Color offset & shadow, Output data control, Color computing control, Color RAM, Priority control, Color RAM control, Sprite control)
* **Features**: Transparency (32 levels of transparency, can also be applied to VDP1 polygons/sprites), shadowing, 2 windows for special calculations, matrix calculations, multi-texturing, bump mapping, color gradients
	+ **3D infinite planes**: Can be manipulated as large polygon objects, with perspective transformation and rotation. Can have curved surface and bumps, and be used for grounds, walls, ceilings, seas, skies, etc.
	+ **Visual effects**: Water, fire, fog, heat haze, misting, reflective water surfaces
* **Rotation picture coordinate calculation**: Geometry processing unit within Scroll picture block, rotation and transformation of 3D planes, manipulates 3D planes as very large polygons, 24-bit fixed-point operations, 28.63636 MOPS (million operations per second)
* **Planes**: 7 layers, 2–6 simultaneous layers (1–4 scrolling 2D backgrounds, 1–2 rotating 3D playfields, 1 back screen)
	+ **2D scrolling backgrounds**: Scrolling, parallax scrolling, single-axis 2D rotation
		- **NBG0**: 16–16,777,216 colors, tilemap (1024×1024 to 2048×2048) or bitmap (512×256 to 1024×512), column/row/line scrolling, scaling
		- **NBG1**: 16–32,768 colors, tilemap (1024×1024 to 2048×2048) or bitmap (512×256 to 1024×512), column/row/line scrolling, scaling
		- **NBG2/NBG3**: 16–256 colors, tilemap (1024×1024 to 2048×2048)
	+ **3D rotating playfields**: Scrolling, scaling, dual-axis 3D rotation, three-axis 3D rotation, 3D infinite ground planes, perspective correct 3D rotation, can be manipulated as large polygon objects, perspective transformation, can have curved surface and bumps
		- **RBG0**: 16–16,777,216 colors, tilemap (2048×2048 to 4096×4096) or bitmap (512×256 to 512×512)
		- **RBG1**: 16–16,777,216 colors, tilemap (2048×2048 to 4096×4096)
	+ **Back screen**: 1 plain background, 1 to 240 colors (1 color/scanline)
* **Tile capabilities**: 8×8 and 16×16 tile sizes, scroll plane up to 8192×8192 pixels, rotating 3D infinite planes up to 4096×4096 pixels each, tile compression, tile-based texture compression, tiled rendering, virtually unlimited draw distance
* **Bitmap capabilities**: Bitmap layers can be used as additional framebuffer (with full transparency), displays VDP1 framebuffer as additional bitmap layer, can rotate VDP1 framebuffer
* **Color palette**: 16,777,216 colors (24-bit), 32,768 colors (15-bit), 65,536 colors (15-bit with transparency)
	+ **Colors per plane**: 16,777,216 colors (3 planes, Lo-Res), 32,768 colors (4 planes), 16–256 colors (6 planes)
* **Bitmap fillrate**:
	+ **2D scrolling planes**: 26.8426–229.09088 MPixels/s
		- **16,777,216 colors on screen**: 26.8426–28.63636 MPixels/s
		- **32,768 colors per plane**: 53.6852–57.27272 MPixels/s
		- **256 colors per plane**: 107.3704–114.54544 MPixels/s
		- **16 colors per plane**: 214.7408–229.09088 MPixels/s
	+ **3D rotation planes**: 26.8426–28.63636 MPixels/s
* **Tile fillrate**: 251.65824–534.77376 MPixels/s
	+ **2D scrolling planes**: 251.65824–503.31648 MPixels/s
		- **Tile fillrate**: 3,932,160 tiles/sec, 65,536 tiles per frame
	+ **3D rotating playfields**: 251.65824–503.31648 MPixels/s
		- **Effective polygon fillrate**: 1 million texture-mapped polygons/sec (500-texel polygons)

### Resolutions

**Progressive**

* 320×224 (Lo‑Res)
* 320×240 (Lo‑Res)
* 320×256 (Lo-Res, PAL)
* 352×224 (Lo‑Res)
* 352×240 (Lo‑Res)
* 352×256 (PAL)
* 640×224
* 640×240
* 640×256 (PAL)
* 704×224
* 704×240
* 704×256 (PAL)

**Interlaced**

* 320×448
* 320×512 (PAL)
* 320×480
* 352×448
* 320×480
* 352×512 (PAL)
* 640×448 (Hi‑Res)
* 640×480 (Hi‑Res)
* 640×512 (Hi‑Res, PAL)
* 704×448 (Hi‑Res)
* 704×480 (Hi‑Res)
* 704×512 (Hi‑Res, PAL)

### Sound

* **SCSP @ 22.58 MHz**:
	+ **Audio channels**: 32
	+ **Sound formats**: PCM, FM, MIDI, LFO
	+ **PCM sampling**: 16‑bit and 8‑bit audio depth, 44.1 kHz sampling sate (CD quality), up to 32 PCM channels
	+ **FM synthesis**: 1–4 operators per FM channel, up to 32 FM channels (1‑operator) or 8 FM channels (4‑operator)
	+ **LFO waveforms**: 4 waveform types (Sawtooth, rectangular, triangular, white noise), up to 32 LFO channels
* **CD‑DA**: 1 streaming CD‑DA channel (16‑bit PCM, 44.1 kHz) from CD
* Stereo audio output

### Memory

* **Total memory**: 5–11 MB (5152 KB system, 39,408 bytes cache, 512–5120 KB cartridge, 1 MB card)
	+ **RAM**: 4.549–10.049 MB (4640 KB system, 18,928 bytes cache, 512–5120 KB optional cartridge, 512 KB optional card)
	+ **ROM**: 532–3092 KB (512 KB system, 20 KB cache, 2 MB optional cartridge, 512 KB optional card)

* **System RAM**: 4.53125 MB (4640 KB)
	+ **2 MB Work RAM**
		- 1 MB High Work SDRAM
		- 1 MB Low Work FPM DRAM
	+ **1.5 MB VRAM**
		- 512 KB VDP1 texture cache VRAM
		- 512 KB (2× 256 KB) VDP1 dual framebuffers
		- 512 KB (512 KB) VDP2 background cache VRAM (tiled texture compression up to 17 MB)
	+ 512 KB Sound RAM
	+ 512 KB CD‑ROM sub‑system buffer data cache
	+ 32 KB battery backup SRAM
* **System ROM**: 512 KB BIOS
* **Internal processor cache**: 39,408 bytes (38.484375 KB)
	+ **SH2**: 8 KB cache (4 KB per SH2)
	+ **SH1**: 4 KB cache
	+ **SCU DSP**: 2 KB RAM cache (1 KB program, 1 KB data)
	+ **SMPC**: 20,976 bytes (496 bytes 4‑bit RAM, 20 KB 10‑bit ROM)
	+ **VDP2**: 4 KB on‑chip color RAM

* **Optional cartridge**: 512 KB to 4.5 MB
	+ **RAM cartridge**: 512 KB to 4.5 MB
		- **Extended RAM Cartridge**: 1 MB or 4 MB Work RAM
		- **Saturn Backup Memory**: 512 KB battery backup
		- **Pro Action Replay**: 512 KB battery backup
		- **Action Replay Plus**: 4.5 MB
			* 4 MB Work RAM
			* 512 KB battery backup
	+ **Saturn ROM Cartridge**: 2 MB (*The King of Fighters '95*)

* **Optional MPEG Video CD Card**: 1 MB (512 KB FPM RAM buffer, 512 KB MROM program)

**Configuration**

System RAM buses, all connected through the SCU:

* **System bus**
	+ SH2 (×2), SCU, SMPC <–> Work RAM, battery backup SRAM
* **Video sub‑system buses**
	+ SCU <–> VDP1, VDP2
	+ VDP1 <–> Texture cache VRAM
	+ VDP1 <–> Framebuffer 0 VRAM
	+ VDP1 <–> Framebuffer 1 VRAM
	+ VDP2 <–> Background cache VRAM
* **Sound sub‑system bus** — SCU, 68EC000, SCSP <‑> Sound RAM
* **CD‑ROM sub‑system bus** — SCU, SH1 <‑> CD‑ROM cache/buffer RAM

**Bandwidth**

* **System RAM bandwidth**: 480 MB/s
	+ **System bus RAM**: 114.54544 MB/s
		- **Work RAM**: 114.54544 MB/s
		- **Battery backup SRAM**: 10 MB/s
	+ **VRAM**: 286.3636 MB/s
		- **VDP1**: 171.81816 MB/s
		- **VDP2**: 114.54544 MB/s (tiled texture compression up to 534 MB/s)
	+ **Sound RAM**: 40 MB/s
	+ **CD‑ROM cache/buffer**: 40 MB/s
* **Internal processor bandwidth**:
	+ **SH2 cache**: 229 MB/s
	+ **SH1 cache**: 80 MB/s
	+ **SCU DSP RAM cache**: 286 MB/s
	+ **SMPC**: 7 MB/s
	+ **68EC000**: 22 MB/s
	+ **SCSP**: 67 MB/s
	+ **VDP**: 286.3636 MB/s
* **System ROM bandwidth**: 20 MB/s
* **Optional cartridge RAM bandwidth**: 44 MB/s to 50 MB/s

### Storage

* **Saturn double-speed CD-ROM drive**
	+ **Storage capacity**: 680 MB
	+ **Data transfer rate**: 320 KB/s
	+ **Access time**: Under 360 ms
	+ **Compatibiity**: CD‑ROM, Audio CD, CD+G, CD+EG, CD Single (8cm)
	+ **Optional**: Video CD, Photo CD, Digital Karaoke, E-book
* **Cartridge slot**: Extended RAM Cartridge, Saturn ROM Cartridge

### Input/Output

* Two 16‑bit bidirectional parallel I/O ports
* High-speed serial communications port (Both SH2 SCI channels and SCSP MIDI)
* Cartridge connector
* Internal expansion port for video decoder card
* Composite video/stereo (JP Part No: HSS-0106)
* NTSC/PAL RF (US Part No.: MK-80116, JP Part No.: HSS-0110)
* S-Video compatible (JP Part No.: HSS-0105)
* RGB compatible (JP Part No.: HSS-0109)
* EDTV compatible (optional)

### Power Source

* AC110 volts; 60 Hz (US)
* AC240 volts; 50 Hz (EU)
* AC100 volts; 60 Hz (JP)
* AC240 volts; 60 Hz (AS)
* AC220 volts; 60 Hz (KR)
* 4 volt lithium battery to power non-volatile RAM and SMPC internal real-time clock
* Power Consumption: 25 W

## External Links

* Sega Saturn technical specifications on segaretro.org