When using this document, keep the following in mind:ntialGeneral Notice

1. This document is confidential. By accepting this document you acknowledge that you are boundby the terms set forth in the non-disclosure and confidentiality agreement signed separately and /inthe possession of SEGA. If you have not signed such a non-disclosure agreement, please contact
SEGA immediately and return this document to SEGA.

de2. This document may include technical inaccuracies or typographical errors. Changes are periodically made to the information herein; these changes will be incorporated in new versions of the
document. SEGA may make improvements and/or changes in the product(s) and/or the
program(s) described in this document at any time.

nfi

3. No one is permitted to reproduce or duplicate, in any form, the whole or part of this document
without SEGA’S written permission. Request for copies of this document and for technicalinformation about SEGA products must be made to your authorized SEGA Technical Services
representative.

Co

4. No license is granted by implication or otherwise under any patents, copyrights, trademarks, orother intellectual property rights of SEGA Enterprises, Ltd., SEGA of America, Inc., or any third
party.
5. Software, circuitry, and other examples described herein are meant merely to indicate the characteristics and performance of SEGA’s products. SEGA assumes no responsibility for any intellectual
property claims or other problems that may result from applications based on the examples
describe herein.

GA

6. It is possible that this document may contain reference to, or information about, SEGA products(development hardware/software) or services that are not provided in countries other than Japan.
Such references/information must not be construed to mean that SEGA intends to provide such
SEGA products or services in countries other than Japan. Any reference of a SEGA licensed product/program in this document is not intended to state or simply that you can use only SEGA’slicensed products/programs. Any functionally equivalent hardware/software can be used instead.
7. SEGA will not be held responsible for any damage to the user that may result from accidents or any
other reasons during operation of the user’s equipment, or programs according to this document.

SE

NOTE: A reader's comment/correction form is provided with thisdocument. Please address comments to :(6/27/95- 002)

SEGA of America, Inc., Developer Technical Support (att. Evelyn Merritt)
150 Shoreline Drive, Redwood City, CA 94065
SEGA may use or distribute whatever information you supply in any way
it believes appropriate without incurring any obligation to you.

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TM

(i)
(i)
(ii)
(iii)
(vi)
(vii)
1
2
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16
27
38
42
51

Index

53

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CONTENTS
Introduction
Manual Layout
Related Manuals
Definitions
List of Figures
List of Tables
Chapter 1 Introduction to Saturn
1.1 Highlights
Chapter 2 Structure
2.1 Hardware Specifications
2.2 System Configuration
2.3 Description of Each Part
Chapter 3 Functions
3.1 CPU
3.2 SCU
3.3 VDP1
3.4 VDP2
3.5 SCSP
3.6 CD-ROM
3.7 Other Items

Saturn Overview
Manual(temporary version 1)
June 6, 1994
Doc. #ST-103-R1-040194© 1994 SEGA. All Rights Reserved.

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READER CORRECTION/COMMENT SHEETKeep us updated!
If you should come across any incorrect or outdated information while reading through the attacheddocument, or come up with any questions or comments, please let us know so that we can make therequired changes in subsequent revisions. Simply fill out all information below and return this form to
the Developer Technical Support Manager at the address below. Please make more copies of this form if
more space is needed. Thank you.
General Information:

Phone

Document number

ST-103-R1-040194

Document nameSaturn Overview Manual

Date

Corrections:
Correction

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pg. #

GA

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Chpt.

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Your NameSE

Questions/comments:

Fax:

Where to send your corrections:(415) 802-3963
Attn: Manager,
Developer Technical Support

Mail:

SEGA OF AMERICA
Attn: Manager,
Developer Technical Support
275 Shoreline Dr. Ste 500
Redwood City, CA 94065

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REFERENCES

KenKyusha New Japanese-English Dictionary
1974 Edition

2.

Nelson’s Japanese-English Character Dictionary
2nd revised version

3.

Microsoft Computer Dictionary

4.

Japanese-English Computer Terms Dictionary
Nichigai Associates
4th version

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1.

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In translating/creating this document, certain technical words and/or phrases were interpreted with theassistance of the technical literature listed below.

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Introduction
This manual gives an overview of the hardware for Saturn, Sega’s Multimedia
Home Entertainment Device, which contains a 32-bit RISC (Reduced Instruction Set
Computer) processor. This manual explains the features and functions of Saturn tothose who develop game software.

Manual Layout

deThis manual consists of the following chapters, supplements, and index.
Introduction to Saturn
The features of Saturn are explained.

Chapter 2

Structure
The internal structure of Saturn plus hardware specifications
are explained.

Chapter 3

Functions
The main functions of Saturn are explained.
• CPU
The main CPU, sound CPU, I/O controller.
• SCU
Control of each bus (A-bus, B-bus, CPU-bus),
DMA transfer, and matrix calculation (DSP).
• VDP1
Control of drawing and defines draw control.
• VDP2Control of the scroll screen and display.
• SCSPSound control of the PCM/FM sound source.
• CD-ROMAn overview of the CD-ROM and MPEG.
• Miscellaneous
Explains the SMPC.

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Chapter 1

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Related Manuals

VDP1
User'sManualde

SATURNOVERVIEW

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VDP2
User'sManualGA

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SCU
User'sManualSCSP
User'sManualSE

SMPC
User'sManual

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Definitions
DSP (Digital Signal Processor)
This high-speed digital processor mainly performs rapid addition and subtraction.
Gouraud Shading
Gouraud is one type of computer algorithm.
This process computes the color of each position (dot, pixel) of each object being
displayed. Places hit by light are bright, and places shadowed are dark.

deC3
An error process that corrects errors when data is read from a CD.

nfi

Frame Buffer
Frame buffer is RAM that stores pictures to be displayed. The line buffer was limited to pictures arranged in a horizontal direction, but with the RAM of the TV
screen size, there you are no longer limits in the horizontal direction.
Pixel
A unit that represents a picture element in a drawing.

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PCM Sound Generator (Pulse Code Modulation Sound Generator)
A method of storing in memory PCM data created from sound, reading the soundfrom memory at the time that the sound is to be played, and outputting the sound.

SE

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Interlace
An image output scan system that obtains the screen image of a single frame byscanning it twice.

iii

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MPEG (Motion Picture (image coding) Expert Group)
An international standard of compression for color motion images (including voice)of television and video. This standard allows the playing of Full Screen, Full Color,
Full Motion, and CD Quality Audio. Besides conforming to the international standard, it also has original special functions.
Parts
Divides textured and non-textured parts in a drawing done by the draw command.

dePerspective
A technique for creating the impression of distance in computer graphics by showing distance objects as small and nearby objects as large.

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SpriteImage patterns that can be rapidly moved and re-drawn. By preparing a number of
sprite patterns and re-drawing them while moving designated coordinates, ananimation effect can be produced in which the game character appears to be moving.
High Resolution
Both the normal TV and special monitor are able to display at a high resolution, but
the special monitor has a higher resolution.

Co

Texture Mapping
A computer graphics technique that allows a pattern to be placed on an object.

SEGA

PCM (Pulse Code Modulation)
A method of dividing sound (wave forms) according to a time axis, and converting
the peak values into digital data. Data found by this method is called PCM data.

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Effect Data
Expresses the resulting sound obtained when a sound created by the sound generator is affected by passing through the DSP.
ReverbAs one type of sound field effect, one can produce the atmosphere of a hall, stage
room, steel plate, etc.
PLL (Phase Locked Loop)
Refers to the phase-locked circuit (IC) that follows to the input signal.

de

IPL (Initial Program Loading)
A list process language. It outputs the designation that loads programs from thedesignated I/O device to the processing device.

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Clipping
Clipping removes all image data located outside of the designated draw access area.
PAL System (Phase Alternation by Line system)
Developed in West Germany, this is a color television broadcasting standard of 625
scan lines and 25 images per second.

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GA

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NTSC System (National Television System Committee system)
Recognized by the FCC (Federal Communication Commission) and applied by
Japan, the United States, South Korea,among others; this standard of color television
broadcasting has 525 scan lines and 30 images per second.

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List of Figures
Chapter 2 Structure
Figure 2.1 System Block Diagram

7

Chapter 3 Functions

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Figure 3.1 SCU System Configuration
Figure 3.2 VDP1 System Configuration
Figure 3.3 Regular Sprites
Figure 3.4 Scaled Sprites
Figure 3.5 Distorted Sprites
Figure 3.6 Polygon, Polyline, Line
Figure 3.7 Configuration of the Color Bank Method
Figure 3.8 Gouraud Shading
Figure 3.9 Mesh Process
Figure 3.10 System Clipping
Figure 3.11 User Clipping
Figure 3.12 VDP2 System Configuration
Figure 3.13 Scroll, Priority Functions
Figure 3.14 Mosaic PatternFigure 3.15 Image Modification by Axis Rotation
Figure 3.16 Image Modification by Screen Axis
Figure 3.17 Cell Format Scroll Screen
Figure 3.18 Bit Map Scroll Screen and Data Setting Relationship
Figure 3.19 Windows
Figure 3.20 Priority Function
Figure 3.21 Color Calculation Function
Figure 3.22 Insertion of the Line Color Screen
Figure 3.23 Shadow Function
Figure 3.24 Blur Calculation Function
Figure 3.25 SCSP System Configuration
Figure 3.26 Tunnel and BGM Reverb
Figure 3.27 Tennis Game Example
Figure 3.28 CD-ROM System Configuration
Figure 3.29 CD-ROM System Data Flow
Figure 3.30 Stream Select Function
Figure 3.31 Window Function
Figure 3.32 Interpolation, Shading, Mosaic Functions
Figure 3.33 Chroma Key Function
Figure 3.34 SMPC System Configuration

vi

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24
24
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51

Chapter 2 Structure
Table 2.1 Hardware Specifications <Main System>
Table 2.2 Hardware Specifications <Subsystem>

6
6

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21
23
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43
50
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52

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Chapter 3 Functions
Table 3.1 CPU Specifications
Table 3.2 SCU System Specifications
Table 3.3 VDP1 System Specifications
Table 3.4 Parts Classification
Table 3.5 Interlace
Table 3.6 Types of Color Operations
Table 3.7 VDP2 System Specifications
Table 3.8 Scroll Screen Functions
Table 3.9 SCSP System Specifications
Table 3.10 CD-ROM System Specifications
Table 3.11 CD Drive Specifications
Table 3.12 Corresponding Standards
Table 3.13 SMPC Functions
Table 3.14 Saturn Digital PAD SpecificationsntialList of Tables

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Chapter 1 Introduction to Saturn

Saturn Overview ManualContents
Highlights

2

1

Highlights• Leading Edge CD-ROM Drive• High-Speed Micro-Processor• Large-Capacity Memoryde• The main CPU is a 32-bit RISC chip
- SH-2 loader that supports a DSP-type computer.

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1.1

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• Memory- 32 Mbits (4 Mbytes)- 4 Mbit (512 Kbyte) CD-ROM

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• Powerful Graphics Functions- Up to 16,777,216 colors- 24 million pixels/Sec (VDP1)- Sprite processor that can display polygons- High performance background processor

2

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SEGA SATURN

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DUAL CPU MULTI AMUSEMENT PLAYERSEGA CD ROM / CARTRIDGE• Improved Sound Functions- 32 Channel PCM sound generator- FM sound generator- Audio-only effect DSP loader

GA• Leading Edge CD-ROM Drive- 32-bit RISC chip SH-1 loader- MPEG (optional)

SE• Development Language- C language, Assembly language

Saturn Overview Manual

3

4

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Chapter 2 Structure

Saturn Overview ManualContents
2.1 Hardware Specifications
2.2 System Configuration
2.3 Description of each Part

6
7
8

5

Hardware Specifications

Saturn hardware specifications are shown below.
Table 2.1 Hardware Specifications <Main System>
SH-2 X 2
CPU

32-bit RISC Chip 28.6MHz / 26.8

CPU BLOCK

RAM

2MB

ROM

512KB
DMA 2 chSCU

DSP 14.3 MHz

deInternal Math Processor

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2.1

RTC 1 MHz (accuracy)

SMPC

Employs Peripheral Interface

Max. 400,000 pixels, 1/60 sec. transfer

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VDP1

Screen Resolution 320 dot (H) X 224 dot (V)VDP2

up to 5 background screens

VIDEO BLOCK

VDP1: 1 MB

RAM

SCSP

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VDP2: 512 KB

PCM 32 ch, max. 44.1 KHz
DSP 22.6 MHz Acoustic effects only

SOUND BLOCK

RAM
CPU

512KB

MC68EC000

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16-bit CISC

11.3 MHz

Table 2.2 Hardware Specifications <Subsystem>
CPU

SH-1
32-bit RISC Chip 20.0 MHz

RAM

512 KB

SE

MPEG AUDIO / VIDEO(optional)

6

RAM 512KB
Screen Resolution 704 dot (H) X 480 dot (V)30 frame/sec animation, 44.1 KHz 16-bit audio

2.2

System Configuration

CARTRIDGE I/F< MAIN SYSTEM >CPU BLOCK

ntial

With a DSP function built-in to the 32-bit RISC chip (SH-2) that is loaded on to themain CPU, the system configuration has greatly improved the processing performance.

< SUBSYSTEM >

SCU

VDP1

de

VIDEO BLOCK

RAM1MBnfi

SH-2 X 2

CD
I/F

SH-1

CD-ROMDRIVE
OPTIONS
MPEG
VIDEO

VDP2

RAM2MB
RAM2KB

MPEG
VIDEO

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RAM512KB

SOUND BLOCK

ROM64KB

ROM512KB

SCSP

SMPC

MC68EC000
RAM512KB

RAM512KBGA

RAM512KB
D/A CONVERTER(SOUND)SE

PAD I/F

Saturn Overview Manual

L

ENCODER

R

AUDIO
OUT

VIDEO
OUT

Figure 2.1 Block Diagram

7

Description of Each Part

The block diagram in Figure 2.1 is explained below.
Main System
SH-2 (X2)

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2.3

Control of the entire system is done by the main CPU. With a RISC type high-speed
CPU, there is a noticeable difference in processing performance over conventional
systems. Processing power has been dramatically improved due to a processor
inside that has an arithmetic unit similar to that of a DSP.

deMC68EC000

The MC68EC000 carries a 16-bit CPU for sound. Processing speed is much fasterthan earlier systems.
RAM/ROM

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The RAM has a total of 32 Mbits, with 16 Mbits in the main CPU, 4 Mbits in thesound CPU, and the remaining 12 Mbits allocated to video. ROM contains the initialhardware program and cartridge as well as the CD IPL program. It also contains a
CD library.
SMPC (System Manager & Peripheral Control)

SCU (System Control Unit)Co

SMPC controls reset of the entire system and interfaces with peripheral devices suchas a control pad. Also, with an internal RTC (Real Time Clock) you can get the date
and time. When the power is off the RTC function is backed-up by a battery.

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The SCU controls all buses (A-bus, B-bus, CPU-bus) and functions as a co-processorof the main CPU. Because the DMA controller is loaded internally, character data
can be transferred to V-RAM when the main CPU is operating.

8

VDP1 (Video Display Processor 1)

ntialVDP1 controls sprites (character). The limitation in the number of horizontal sprites
of previous systems has been eliminated, allowing more sprites (characters) to be
displayed. Polygons can also be displayed.
VDP2 (Video Display Processor 2)

VDP2 controls display of the background screen (scroll screen) as well as the display
priority order. This has expanded the number of scroll screens that can be displayed
at the same time to a maximum of five, and enables the screen to be moved up,
down, right, and left and to be rotated.
SCSP (Saturn Custom Sound Processor)de

The SCSP controls the sound of the PCM/FM sound generator. It supports the FM
sound generator of conventional systems and can support PCM sound. Tone quality
has improved to CD-D/A (Compact Disc - Digital / Audio) levels.
Cartridge I/F

PAD I/F

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This is the connector I/F for the cartridge. A maximum of 57 MB area has been
provided.
This is a control pad connector I/F. Two are planned to be loaded into the main
system.

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D/A Converter, Encoder

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This changes the digital signal of sounds to an analog signal (D/A converter). In thecase of color, analog RGB is converted to video signals (encoder).

Saturn Overview Manual9Subsystem
CPU

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The CPU manages mechanical control, error correction (C3), and CD file management.
RAM/ROM

RAM is used as CD buffer RAM, MPEG work RAM, and in the data cache for CD
error correction. ROM contains programs such as the CPU CD BIOS.
CD-ROM Drive

Saturn employs a X2 speed CD-ROM drive.

de

MPEG (optional)

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This standard allows the playing of Full Screen, Full Color, Full Motion, and CD
Quality Audio. Up to 72 minutes (30 frames per second) of images and sounds canbe recorded on a single CD. In addition, there are various application capabilities
that not only output the stretched images, but capture them within the system andenable their processing using MPEG technology.

10

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Chapter 3 Functions

Saturn Overview ManualContents
3.1 CPU
3.2 SCU
3.3 VDP1
3.4 VDP2
3.5 SCSP
3.6 CD-ROM
3.7 Other Items

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38
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11

3.1

CPU

Table 3.1 CPU Specifications• RISC Type Instruction Set• Internal and External 32-bit buses
SH-2• Cache 4 Kbyte• Internal Math Processor

SH-1• RISC Type Instruction Set• Internal A/D Converterde• Clock 28.6 MHz / 26.8

ntial

The main CPU has a 32-bit RISC chip with built-in DSP function. The sound block
has a 16-bit CPU MC68EC000. The subsystem has a SH-1. The specification of each
CPU is shown in Table 3.1.

• Internal 32-bit bus and External 16-bit bus• Clock 20 MHz

nfi• Cache 4 Kbyte• Internal Math Processor
MC68EC000• Internal 16-bit bus and External 16-bit bus• CISC Type Instruction Set

Co• Clock 11.3 MHz

SEGA• SMPC (System Manager) is the processor configuration.
See “3.7 Other Items” for more about functions.

12

SCU

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3.2

The SCU smoothly executes the interface of more than one processor connected toCPU-bus, A-bus, and B-bus. Further, inside is a DMA controller, interrupt controller,
and DSP.
System Configuration

The SPMC is connected to the CPU-bus and controls the system reset signal as wellas the control pad.

de

The A-bus is connected to a device that provides programs such as cartridges and
CDs.

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The SCU interrupt controller controls interrupt from A-bus, B-bus, and the SMPC. It
also supports timer interrupt, can cause the screen display to synchronize and interrupt (INT signal) (Figure 3.1).

INT Signal
CPUCo

CPU-bus

ROM

SCU

B-Bus

SMPC

GA

RAM

A-Bus

SE

Figure 3.1 SCU System Configuration

Saturn Overview Manual13

Table 3.2 SCU System Specifications
No

Item

Specification

Remarks• 32bit X 32bit → 48bit• 14 MHz

1
DSP• Program RAM 32bit X 256word• DATA RAM 32bit X 64word X 4

DMA• CPU 3 ch, DSP 1 ch
• 3 level, stack 1 set• Able to start by interrupt• Indirect mode

Interrupt Control• Timer (2ch) synchronized with screen• Interrupt control from external terminal

A-bus Control• A-bus (external bus) bus sizing• Wait control• Burst size setting• Refresh control

B-bus Control• B-bus (internal bus) control

5

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4

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• DMA command
2

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System specifications of the SCU are shown in Table 3.2.

• VDP1, VDP2, SCSP only

Functions

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SCU functions are shown below.
• Data transfer within A-bus, B-bus, and CPU-bus• Matrix calculations by DSP• SCU internal interrupt control by interrupt controller• Data transfer within Main CPU, Internal DSP, A-bus, and B-bus

de

The SCU has a CPU I/F, A-bus I/F, and B-bus I/F and smoothly executes the interface to multiple processors, which are connected through their respective I/F andbuses. This also allows programs in the main CPU to be transferred to the DSP
within the SCU. Also, while data is being transferred between the A-bus and B-bus,
the work area can be accessed using the CPU-bus from the CPU, and process can be
executed using independent buses in parallel.
• Interrupt Control

nfi

Interrupt that extends to other processors executes through the SCU. For example,
to display the volume level on screen, a screen display request interrupt from the
SCSP for the SCU occurs. SCU recognizes the interrupt and issues the interrupt
while synchronized with the screen. Interrupt can then be issued with respect to any
point (dot) on the screen.
Internal DSP

Operating FrequencyCo

SCU has an internal DSP. This has been provided in order to implement processes
difficult to implement when the load to the main CPU has been excessive.

SE

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The operating frequency of the DSP inside SCU runs at a frequency of 1/2 the main
CPU. See the Main CPU manual concerning the operating frequency of the main
CPU.

Saturn Overview Manual

15

3.3

VDP1

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VDP1 controls sprites.
Compared to conventional systems, drawing speed is exceptionally fast, and because there is no limit in the number of horizontal sprites, more sprites (characters)
can be displayed. Polygons can be displayed as sprite applications.
System Configurationde

The VRAM and two frame buffer screens are connected to VDP1 (Figure 3.2). The
VRAM draw command is set through the SCU from the CPU. VDP1 reads drawcommands from the VRAM and writes (draws) draw data to the frame buffer. Information controlling draw is set in the system register inside VDP1. Drawn frame
buffer data is displayed in the TV through VDP2 that controls image display.

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VRAM

VDP1
SCU

SystemRegisterCo

CPU

Frame Buffer

Frame Buffer

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Figure 3.2 VDP1 System Configuration

16

VDP2

TV

Table 3.3 shows the VDP1 system specifications.

No

Item

1

Texture Parts
Display

Specificationnti
alTable 3.3 VDP1 System Specifications• Regular Sprites(normal sprite, horz. 8~504 dot,
vert. 1~255 dot)
• Expand/Contract Sprite

Remarks

Up-down-left-rightreverse by all sprites ispossible(any size can be designated by verticalhorizontal 1 dot units)• Distorted Sprite

2

Non-Texture Parts
Display• Quadrilateral polygon• Polyline• Line4

Draw Method

5

Simultaneous Colors

6

Memory Capacity• Semi-transparent associated parts• Half brightness• Shadow• Mesh• Gouraud Shadingnfi

Color Calculation

You can have a three
sided polygon andpolyline if two adjacentpoints have the same
coordinates

Gouraud shading can be
combined with semitransparent or halfbrightness• Double Frame Buffer Method(Can enlarge, reduce, rotate, and modify
the entire plane of the frame buffer.
Can designate the delete range anddelete data of frame buffer.
Can set write local coordinates.
Can designate clipping of rectangulararea.)

Co3

de(can designate any 4 vertices)• 16, 64, 128, 256, 32768 colors

16, 64, 128, 256
for high resolutionGA• VRAM 4 Mbit
(Character Generator, for all types oftables)SE• Frame buffer 2 Mbit X 2 sides(Both 2 sides can be used as bit map.
One side is displayed.)

Saturn Overview Manual

17The main functions of the VDP1 are shown below.
• Draws parts (character line)• Designates color mode
• Color calculation• Mesh process• Designates clipping coordinates and relative coordinates• Display control of frame bufferntialFunctionsdeParts, color mode, and coordinates are controlled by the VRAM command table.
Control of the frame buffer display is done by the system register.
Parts

Table 3.4 Parts Classification

Classification

Parts Name

Texture Parts

Regular sprite

Function

Defining Method

Character, up-down,
left-right reverse

Read direction of 1
vertexCharacter, up-down,
left-right reverse,
enlarge-reduce,
expand-contract are
possible

Read direction of 2
vertices, or readdirection of fixed
points and width

Transformed sprite

Character, up-down,
left-right reverse,
enlarge-reduce,
expand-contract,
rotation, twisting are
possible

Read direction of 4
vertices

Polygon

Quadrilateral

4 vertices

Rectangular sprite

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A
R
T
S

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Non-Texture Parts

18

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Parts drawn by VDP1 are divided into texture and non-texture parts depending onwhether or not there is an original picture. Table 3.4 shows part classifications.

Inside is painted solid

Polyline

Quadrilateral

4 vertices

Line

Straight LineStart and End points

Texture Partsntial

Sprites draw character patterns. Character patterns define pixel data as character
pattern tables in VRAM.
Regular Sprites

Normal rectangular sprite.
The pattern of the original picture can be inverted up , down, and left and right.
This can be done in any sprite mode (Figure 3.3).

< Drawings >de< Original >Left-Right
ReverseUp-down
Up-Down
Reverse Left-Right Reverse

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NormalFigure 3.3 Regular Sprites
Scaled Sprites< Original >Co

For sprites that can be enlarged and reduced, it is only possible to zoom in and out
vertically and horizontally (Figure 3.4).

< Drawings >GA

Reduce VertSE

NormalReduceHorz.

Expand Horizontally
and VerticallyExpand Horizontally

Saturn Overview Manual

Expand VerticallyFigure 3.4 Scaled Sprites

19

Distorted Sprites

ntialThese are sprites that can be distorted. The original picture can be distorted to any
shape by designating four vertices of the character and enlarging, reducing, rotating,and reversing the picture in any way. If viewed as a polygon, it would be the sameas a texture-mapped polygon.

ROTATETWISTPUSH IN TOWARD CENTER

Co

PUSH AT1 POINT

CHANGE SHAPE

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PULL AT1 POINTdeORIGINAL

SHIFT ALL POINTSSEGAFigure 3.5 Distorted Sprites

20Non-Texture Parts
PolygonPolyline

This is a quadrilateral connected by four lines.
Line

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This is a four-vertex polygon. It is different with a sprite in that the flat surface
encompassed by the four points is painted over by one color. Sprites have an original picture whereas polygons do not.

POLYGONnfi

deThis is a line of one color drawn between two points.

POLYLINE

Co

LINE

Figure 3.6 Polygon, Polyline, Line

Display

A common TV is used as a display apparatus. NTSC format is the TV standard ofboth Japan and the U.S. Europe uses the PAL format.

GA

TV display is done by reading data from lead of the frame buffer for each frame (1frame per 1/60 sec.).
Normally, one frame is equal to one field, but one frame that is interlaced is treatedas two fields, allowing the vertical resolution to be doubled (one frame per 1/30
sec.). There is single and double interlace, as shown in Table 3.5.
Table 3.5 Interlace

SE

Double Interlace
Single Interlace

Odd numbered line, a different image is shown by even numbered lines

Odd numbered line, the same image is shown by even numbered lines

Saturn Overview Manual21Color Mode Designationnti
alThere are three methods of designating color modes for textured parts: the color
bank, RGB code, and color look-up. Non-textured parts have pixel data for color
designation.
Color Bank Method

MSB

LSB

Palette Code

nfi

Color Bankde• Combining color bank with 16, 64, 128, and 256 color palette codes, referencescolors stored in the VDP2 color RAM.
• VDP2 color palette is selected by the color bank. Color from the color palette is
selected by the palette code.
• 16, 64, 128, 256 colors can be expressed by 1 character.
• Data written by the color bank method is divided and processed by the VDP2
color operation, priority, color bank, and function bits of the palette code.

Co

Priority
Color Operation

Figure 3.7 Configuration of the Color Bank Method
RGB Code Generation

Color is expressed by five bits of respective RGB (red, green, blue) luminance.
Color Look-up Table

SE

GA

Colors are selected from the 16 colors defined in the color look-up table. One color
with 16 bits can be of either RGB code or color bank code.

22Color OperationntialGouraud Shading, shadow, half-brightness, and semi-transparent color operations
can be designated by VDP1. Table 3.6 shows the types of color operations.
Table 3.6 Types of Color Operations
TYPE

DESCRIPTION

A foundation at half brightness is added to the original at halfbrightness. The result is drawn in the frame buffer.

Half-Brightness

An object at half the brightness of the original picture is drawn
in the frame buffer. The foundation cannot be seen because iis written over and the brightness of the original is reduced to
half.

Shadow

The foundation at half-brightness is re-drawn in the frame
buffer. Here, a shadow of the character shape in the originalcan be created. The character of the original is used only in th
shape of the shadow and color data is ignored.

Gouraud Shading

An object in the original picture to which Gouraud shading isapplied is drawn in the frame buffer.

Gouraud Shading
Semi-transparent

The brightness of an object in the original picture to which
Gouraud shading is applied is reduced to half, and foundation
at half-brightness is added. The result is drawn in the frame
buffer.

Gouraud Shading
Half Brightness

The brightness of an object in the original picture to which
Gouraud shading is applied is reduced to half, and the object idrawn in the frame buffer.

nfi

Co

Gouraud ShadingdeSemi-transparent

Gouraud shading can be applied to parts drawn by RGB, and interpolates color
between polygon vertices which causes a flat surface to appear curved.

SEGA

A surface can appear to be curved by giving brightness correction values to the four
vertices of a polygon and applying Gouraud shading within these four vertices.
Gouraud shading can be applied to polylines and lines as well. Figure 3.6 shows anexample of Gouraud shading.

Saturn Overview Manual

23

nti
al
de

Figure 3.8 Gouraud Shading

Mesh Process

0 1 2 3 4 5 6 7 8 9"X coordinate value + Y coordinate
value" is painted only for evennumbered pixels; odd numberedpixels are skipped and not written.

Co

0
1
2
3
4
5
6
7
8
9

nfi

Mesh can be applied to all parts. A checkered pattern (every other dot) is drawn tothe part in which the mesh is applied.

: not painted: painted

SE

GA

Figure 3.9 Mesh Process

24ClippingntialClipping allows only the set display area to be drawn and cuts away any excess.
Clipping includes system clipping that sets the system draw area, and user clippingthat enables any setting by the software.
System Clipping

System clipping is always in effect while drawing. and the inside of the set area isdrawn (see Figure 3.10).

(0,0)

de

System Clipping Area

nfi

System clipping can be designatedby
fixing the upper left coordinate (0,0)anddefining the lower right coordinate

Lower Right Coordinate
TV

User Clipping

Co

Figure 3.10 System ClippingGA

User clipping can be selected by the software. Choose whether to make user clipping effective for each part, or the inside or outside of the user clipping set area ofthe effective area.

(0,0)

User Clipping Area
User clipping area can be
designated by selecting theverticies of the upper left andlower right coordinates.

SE

Upper Left
Coordinate

Saturn Overview Manual

Lower Right Coordinate
TV

Figure 3.11 User Clipping25

Frame Bufferntial• The frame buffer is divided into two screens, the display frame buffer and draw
frame buffer. Read/Write access from the SCU to the frame buffer is performed
only for the draw frame buffer. The display frame buffer becomes a back-end
bank and cannot be accessed.

SE

GA

Co

nfi

de

• By reading the frame buffer, the read start coordinate and next dot to be read canenlarge, reduce, and rotate the entire frame buffer surface by giving X and Y
direction displacement, which designates the location.

26

3.4

VDP2

nti
al

VDP2 determines priority of display of the scroll screens and the entire screen (including sprites). Simultaneous display of scroll screens has been expanded to a
maximum of five screens. A screen can be moved up, down, left, and right, androtated. Priority (display priority order) can be programmably set on each character.
System Configuration

VDP2 has VRAM connected to it and color RAM built-in. Image data is definedfrom the CPU through the SCU to VRAM and color RAM.

nfi

de

Data defined in VRAM is read according to settings of the register and becomesimage data of each scroll screen. This data, VDP1, as well as image data sent fromthe external image circuits determine the display priority order according to theregister setting, then become display image data. Display image data is converted todisplay color data and output to the TV (Figure 3.12).

SCU

GA

CPU

Co

VDP1

External Image
Circuit(optional)

VDP2
Register

TV

Color
RAM

VRAM

SE

Figure 3.12 VDP2 System Configuration

Saturn Overview Manual27

Table 3.7 VDP2 System Specifications

Item

1

TV Screen

Specification

Remarks

nti
al

No

• Horizontal Resolution
Vertical resolution of 256
Select from 320, 352, 640, 704 pixels pixels and 512 pixels arefor PAL only.
• Vertical Resolution
Select from 224, 240, 256 pixels(for non-interlace)
Select from 448, 480, 512 pixels(for Interlace)

Character

Bit map format is also
• Character Sizepossible.
Select from 1 X 1 cell and 2 X 2 cell
• Number of character colors
Select from 16, 256, 2048, 32768, and16,770,000 colors.

3

Normal Scroll
Screen• Max. no. of simultaneous screens is 4
• Scrolls horizontally and verticallyde2• Mosaic function

nfi• Can line scroll• Scrolls vertical cells• Reduces to 1/4, enlarges to 256X
Rotation Scroll
Screen• Max. no. of simultaneous screens is 2 Normal scroll screen can
not be displayed when 2• Can Enlarge, Reduce, Rotate
screens are displayed• Rotation parameter can be switched
inside screen• Special Screen processing bycoefficient table

5

Windows• Normal window 2 screens• Sprite window 1 screen

6

Priority

7

Screen Operation

Co

4• Line window possible

GA• Priority of each screen is programmable• Priority can be switched in character
units and dot units• Color operation for up to 4 screens is
possible• Color operation rate 32 steps

SE• Color offset function• Shadow function

28

Functionsnti
alVDP2 has a scroll function for controlling the display of the scroll screen, and apriority function for determining the display priority order (Figure 3.13).

Determine Priority
Color Operation
Color Offset
Shadownfi

Priority Functions

Magnify and Reduce
RotationLine Scroll
Vertical Cell Scroll
Mosaic Process
Windowde

Scroll Functions

Figure 3.13 Scroll, Priority Functions

Scroll Functions• Scroll Screen

Co

Scroll has a scroll screen for displaying pictures and windows for display control.
Scroll screen includes a normal scroll screen that can change the number ofdisplayable screens, and a rotation scroll screen that can rotate a screen.

SE

GA

Table 3.8 shows the functions of the normal scroll screen and rotation scroll screen,
and number of character colors.

Saturn Overview Manual29

Table 3.8 Scroll Screen Functions
Normal Scroll Screen
Screen 0
Enlarge/Reduce

Screen 1

Screen 2

1/4 X ~ 256 X

Rotation

Rotation Scroll Screen
Screen 3

Screen 0

Screen 1ntialFunctionno

any factor

no

yes

Line Scroll

yes

yes

no

no

Vertical Cell Scroll

yes

yes

no

no

no
yes
(only in horizontal)

no

no

yes

Mosaic Process

yes

Displays Bit Map

yes

yes

no

Select from Select from Select from Select from Select from Select from
16

16

16

16

256

256

256

256

2048

2048

32768

32768

16

16

256

256

2048

2048

32768

32768

16.77 mil.

16.77 mil.

nfi

16.77 mil.

deCharacter Color
Numberno• Enlarge/Reduce Function• Line Scroll Function

Co

Enlarge and reduce the entire screen horizontally and vertically. Reduced display
horizontally limits the number of screens.
Scroll up, down, right, and left each line as well as enlarge and reduce horizontally.
This creates the feeling of distance, such as the road of a driving game.
• Vertical Scroll Function

Scroll up and down in units of horizontal cells. It can create depth as in a vertical
scroll game.
• Mosaic Function

SEGA

All scroll screens are divided horizontally and vertically, and the color of upper-leftdots in each area are displayed per dots in that area.

30

Horizontal direction
Mosaic Size

Area A

Area B

Area CArea DdeVertical direction
Mosaic Sizential

The color of the dot in the upper
left corner of each area is usedin all dots within that area.

Rotation Function• Rotation Display

nfi

Figure 3.14 Mosaic Pattern

Co

The rotation scroll screen rotates along the coordinate axes (X, Y, Z axes) and thescreen axis vertical to the TV screen. Two surfaces can be displayed at the sametime.

Z axisX axisSEGA

Y axisX axis Rotation

Y axis Rotation

Z axis Rotation

Figure 3.15 Image Modification by Axis Rotation

Saturn Overview Manual

31

nti
al

de

Figure 3.16 Image Modification by Screen Axis
• Rotation• Simultaneous Display by Screen Divisionnfi

Rotation calculation is done by the hardware according to designated parameters.
This means that rotation display can be done without straining the CPU load.
Twisted images can be displayed since coordinates can be calculated and different
values applied to each dot.
The image of two screens can be displayed by showing one screen of the rotation
scroll screen.
Scroll Screen Structure

Co

The two scroll screen formats are the cell format and the bit map format. The cell
format, as in conventional home game devices, displays an arrangement of cells.
The bit map format, as with the personal computer, displays a picture that corresponds to each dot on a screen.
• Cell Format

SEGA

The cell format scroll screen is a picture pattern consisting of cells (eight horizontal
dots by eight vertical dots), character patterns (an arrangement of cells), pages (anarrangement of character patterns), planes (an arrangement of pages), and maps (anarrangement of maps). Figure 3.17 shows the structure of a cell format scroll screen.

32

H8 dots X
V8 dots

H1 cell X
V1 cellor
H2 cells X
V2 cells

Page

Plane

32 X 32or
64 X 64
characterpatterns(64X64 cells)

H1 page X
V1 pageor
H2 pages X
V1 pageor
H2 pages X
V2 pages

H2 plains X
V2plains(Normal Scroll Screen)or
H4 plains X
V4plains(Rotation Scroll Screen)de

NOTE: V = vertical
H = horizontal

Map

nti
al

Character
Pattern

Cell

Figure 3.17 Cell Format Scroll Screen

nfi• Bit Map Format

The bit map scroll screen consists of a bit map pattern 512 dots or 1024 dots horizontally and 256 dots or 512 dots vertically in size. Figure 3.18 shows the configurationof the bit map scroll screen.

Co

Bit Map

1 dot

GA

NOTE: V = vertical
H = horizontal

H 512 X V 256 dots
H 512 X V 512 dots
H 1024 X V 256 dotsor
H 1024 X V 512 dots

Figure 3.18 Bit Map Scroll Screen and Data Setting Relationship

Windows

SE

Windows are classified into three types depending on the way the area is designated(coordinate designation).
• Normal Rectangular Window

Designated by two coordinate points: start and end.
• Normal Line Window

Designated by the start and end points of each line coordinate.
• Sprite Window

Designated by sprite character patterns.

Saturn Overview Manual33

TV Screen

InsideWindow

InsideWindow

OutsideWindow
Normal Rectangle Window

TV Screenntial

TV Screen

Inside Window

OutsideWindow
Normal Line Window

OutsideWindow
Sprite Window

Figure 3.19 WindowsdePriority Functions

The display priority order of sprites and scroll screens is determined by a 3-bit
priority number. The sprite priority number can set a maximum of eight values; oneof which is designated by character units.
Determining Priority

Priority
Number=4transparent

GA

transparent

Priority
Number=2

Co

Priority
Number=6

nfi

The scroll screen priority number is designated in normal surface units. (This can bechanged by character units or dot units using special priority function.)

Top Image

Priority
Number=1transparent

Second Image

Third Image

Figure 3.20 Priority FunctionSE• Special Priority Function
Priority numbers that correspond to each scroll screen can be changed by characteror dot units. This function the priority of only the area within the scroll screen to bechanged, which causes one scroll screen to appear like as more than one screen.

34

Color Calculation Functionntial

By adding multiple screens of color data, the color calculation function produces aneffect that makes the back screen appear to be seen through the front screen. This isnormally done by two screens, the top image and the second image, but can be donewith up to four screens if the expanded color calculation function is used.

Priority Number = 2

transparent

transparentdePriority Number = 4

nfi

Back
ScreenFigure 3.21 Color Calculation Function

SE

GA

Co

• Line Color Screen Insert
The line color screen forces the top image part of the designated screen to be inserted
as the second image, and induces color calculation. The pre-inserted second image
becomes the third image in the area of the inserted line color screen, and the third
images drops one to become the fourth image. Figure 3.22 shows insertion of theline color screen.

Saturn Overview Manual

35

nti
al

Priority number =6 Priority number =4 Priority number =2 Priority number =1
transparent

transparent

transparent

screen the line color screen
has been inserted into

screen the line color screen
has been inserted into

top imagesecond image

back screen

back screen

nfiback screendeline color screen

third image

fourth image

Co

Figure 3.22 Insertion of the Line Color Screen

Shadow Function

The shadow calculation function adds a shadow in the shape of the sprite characteron all screens.

Frame Buffer Data

Scroll Screen

Output ScreenGAtransparent+

SE

Shadow Sprite=

Normal Sprite

Figure 3.23 Shadow Function• Blur-Calculation Function

The blur-calculation function adds the horizontal color data of one designated screen
at a fixed rate, and is able to create an effect of a blurred distant background.

36

Priority number = 4

transparent

transparent

Screen A

ntialPriority number = 6

Priority number = 2

Screen C
Screen designatedto be blur-calculated

Screen B

Second ImageTop Image
Screen C

deScreen B

Screen C

Screen A

nfi

Replaced as a result of
blur-calculation onscreen C

Second Image

Blur-Calculated
Screen C

Co

Screen B
Color Operation

Color Function used in Screen C

Screen B

Display Image
Blur-Calculated
Screen C

GA

Screen A

Figure 3.24 Blur-Calculation Function

The sum of color data is forced to be as second image in the area where the top or
second image is the designated screen. The blur-calculated picture can be displayedby performing color calculation on the second and top images.

SE

Color Offset Function

The color offset function displays and adds (or subtracts) the offset value for thescreen color data, and is used in fade-in and fade-out. Designate whether to use thecolor offset function in each screen.

Saturn Overview Manual

37

3.5

SCSP

nti
al

SCSP is custom sound LSI that unites PCM (FM) sound generation with a soundonly DSP. The goal of the audio function is to provide higher tone quality with allinterfaces for increasing expandability. Capable of creating many sounds, the operation part provides a performance that rivals that of a synthesizer. The DSP cancreate multiple sound fields, such as each type of sound field play as well as the
special effects of 3D sound positioning.
System ConfigurationdeThe main CPU, sound CPU, sound memory, and D/A converter are all connected to
the SCSP. In the sound system, these can operate independent of the main processor.

nfi

The main CPU transfers the sound (CPU, DSP) program and wave form data to the
SCSP sound memory through the SCU. The sound CPU transfers wave form data to
the register inside the SCSP. SCSP reads delayed data for producing sound memory
wave form data as well as the effect. The audio is mixed and output as soundthrough a D/A converter.

Co

SCU

Interface

CPU Program

PCM(FM)PCM Sound Data

DSP

DSP Delayed Data

SCSP

GA

Sound CPU
MC68EC000

MIXER

SE

D/A Convertor

Figure 3.25 SCSP System Configuration

38

Sound Memory(DRAM)

System Specifications

Table 3.9 SCSP System Specifications
No

Item

Specifications

1

Sampling Frequency• 44.1 KHz

2Audio Synthesis System• PCM, FM Format

3

Audio Process Slot Number• 32 slots

4

Wave Form Data Format• 8-bit, 16-bit formats

5

Each function type

• Envelope

Remarksde

2'S complementntialTable 3.9 shows the SCSP system specifications.

• Loop Process• LFO
6

Effect from internal DSP• Reverb, Chorus, etc.

7

Other functions• DMAC ......................... 1ch

nfi• Timer ............................ 3ch• MIDI ............................. IN/OUT each 1• External D/A Input ....... Stereo1 system

Co

Functions
The main functions of the SCSP are listed below.

SE

GA• Frequency control• Volume control• FM operation• LFO (Low Frequency Oscillator) modulation function• Digital / Audio mixing• Effect from DSP (reverb)

Saturn Overview Manual39Effectnti
alBecause the SCSP DSP can create multiple sound fields, it is possible to have different settings for BMG sound and game sound.

de

For example, in a racing game, reverb would be applied to the concert grounds as
BGM while reverb could be applied at the same time in producing an atmosphereinside a tunnel for the game.

r

rrrr

roa

nfi

Reverb applied tocreate a tunnel
atmosphere
Effect applied to
BGM (CD voice)Co

Figure 3.26 Tunnel and BGM ReverbSE

GA

In the DSP, the effect can be applied to CD audio because the audio signals from thesound generator, and sound signals from the CD are input. Because the CD output
level can be controlled through the SCSP, the sound signal from the sound generator
and CD can be balanced and therefore the sound from the sound source will still be
audible without being “hidden” by the CD sound. Thus, concealing the CD soundwill not conceal the sound of the sound generator.

40

Sound PositionntialWith a high performance digital mixer, the SCSP can control the positions of allsounds in real time. As a result, effective sounds can be produced on the screen withcharacter positions. This process can be done by the DSP as well. In this case, when
the character moves slowly, the sound orientation will move smoothly because more
intricate settings can be made. A sense of depth (distance) can be created by adding
reverb to this positioning.

pachinndepachinn

A sense of distance can be created bychanging the echo according to the
distance. This includes fixed positions (pan)
also.

nfi

Sense
ofdistancLCopachinn

R

Fixed Position (pan)Figure 2.27 Tennis Game Example

SE

GA

Besides this, indoors, outdoors, and wide open spaces can be expressed dependingon the type of reverb. Also, the type of reverb can also be set for all conditions, suchas a hall, stage room, steel plate, etc.

Saturn Overview Manual

41

3.6

CD-ROMntial

The CD-ROM system has its own CPU and buffer RAM, and can operate independently of the main system. By setting in advance conditions from the main system,
flexible buffer management that suits the application configuration is attained.
System ConfigurationdeThe CD-ROM system operates only by giving commands through CD I/F from themain system. The sub-CPU interprets commands from the main system, controls the
CD-ROM drive and CD buffer, reads data, and plays video and audio. Audio andvideo playing employs the MPEG international video compression standard, anduses the exclusive “MPEG/Video LSI” as well as “MPEG / Audio LSI.” The system
configuration is shown in Figure 3.28.

nfi

The sub-CPU, CD buffer, frame buffer, C/D I/F are connected to the MPEG / Video.
Compressed image data is received from the CD buffer and regeneration image datais written (drawn) to the frame buffer. Drawn frame buffer data carries out the effectaccording to register settings and displays in the display device through VDP2 thecontrols screen display; or it is transferred to VDP1 and VDP2 VRAM through CD I/
F and SCU.

<CD-ROM System>
CD Buffer

Co

MPEG / Audio receive compressed audio data from the CD buffer and outputs
stereo 1ch audio data. This audio data is output through the SCSP as sound.
<Main System>SCU

CD Drive

A-bus

Audio

CD I/FGA

SubCPU(SH-1)

Speakers

B-bus

MPEG
Audio

SE

MPEG
Video

Image

SCSP

VDP2

Frame
BufferFigure 3.28 CD-ROM System Configuration

42

TV

Table 3.10 CD-ROM System Specifications
No

Item

Specifications

ntial

CD-ROM system specifications are shown in Table 3.10, and CD drive specifications
are shown in Table 3.11.

1

G/A Register width

16 bit2

Seek Time

400 msec (1/3 access time, double speed
rotation time)3

Rotation Speed

Normal time: 620~1680 rpm
2X speed: 1240~3360 rpm

4

CD Read Speed

Remarks

Normal speed: 75 sectors/sec = 150KB/secde2X speed: 150 sectors/sec = 300KB/sec
Tray Open & Close Method Top loading

6

Memory Capacity

RAM 512KB (for CD buffer) ROM 64KB (forBIOS) RAM 512KB (for MPEG)

7

Data Transfer Speed

Max. 8MB/sec, max. 4MB/sec while MPEG isin operation

8

LED

Flashes according to CD operation statusnfi

5

Table 3.11 CD Drive Specifications
Item

1

CD Play

Specifications

Remarks

Track/Index designation play

Co

No

Frame address (in absolute time) designation
play
Play restarts (Cancels pause, controls pick-up
movement)
Repeat playable to control CD-DA and CD-ROM bycommands of identical format

Other

Retrieve subcode
Corresponds to Multi-session
Corresponds to Emphasis
Decode and error correction corresponding
to CD-ROM XA(Subheader recognition, ECC process, Read
retry process)

SE

2

GA

Scan regeneration

Saturn Overview Manual

43

Functions

de

nti
al

The main functions of the CD-ROM system are shown below.
• Stream select• Parallel processing• MPEG functions-Video play
-Pause screen play (high detail, JPEG)-Window function-Visual effect function(mosaic, shading, Chroma key, fade in / fade out)
- play function-Pause, freeze, frame feed, slow motion-MPEG buffer function

CD-ROM

nfi

CD-ROM system first stores data read from the CD-ROM to the CD buffer. The
stored data reads/writes to the main system or MPEG in response to commands
from the main system. Figure 3.29 shows the data flow of the CD-ROM system.

MPEG Buffer

Play

DecodeCopy Move

CD buffer(buffer section)GA

CD Block

Write

Co

Read

CD Read = Read

Host

MPEG Decoder

VDP2

Write

Display
MPEG Frame Buffer

Write

Image Data

Data transfer Register

Retrieve

Write

MPEG Register
RetrieveSE

Host

Figure 3.29 CD-ROM System Data Flow

44

Stream SelectntialData flow from the CD-ROM is called a stream. A stream has audio data, image
data, and program data. The stream select function selects the classification of dataand sends it to the main system and MPEG (Figure 3.30). Control content of thestream select function is shown below.

de• Stream data accumulates in the CD buffer and is selected in response to thedata classification.
• Data from devices such as a CD-ROM and MPEG decoder are controlled
uniformly.
• Stream select conditions are set by command.
SelectV→↓

CD-ROM XA

D A V D A V
V : Video
A : Audio
D : Data

Video

nfi

A→

Buffer↓D→

Main
System

Data

Co

↓

Audio

Figure 3.30 Stream Select Function

Parallel ProcessingSE

GA

The CD-ROM system reads streams, it also selects streams and controls the CD drive
independently of the main system. Further, parallel processing can be done sincemore than one stream selection mechanism is set.

Saturn Overview Manual45

MPEG Function

ntialMPEG plays animation with sound added.
Image data is compressed to 1/50 and audio data is compressed to 1/10 before
being played. Therefore, 74 minutes can be recorded on a CD. An exclusive LSI
allows a game with animation (movie) of high image quality to be played without
overloading the CPU.
MPEG / Video Function

Saturn’s MPEG/Video has various special functions that are exclusively customized
for Saturn.

deWindow Function

MPEG Play Imagesnfi

As shown in Figure 3.31, this function cuts out part of the image played and displays
it at any size on the TV screen. This function allows the display position of the
MPEG play image and display size to be changed, to select and display one of several screens, and zoom in, and zoom out.

Expressions
such as "openwindow" areallowed

Co

Animation (object 1) Animation (object 2)

Image from VDP1, 2

Animation (object 3) Animation (object 4)SE

GA

Figure 3.31 Window Function46

24 bit, full color

Mosaic size horizontal direction

deMosaic size
vertical direction

Shading

Displays average of right, bottom,
and lower right dots

+
+ +

+
+ +

4

4

+
+ +

+
+ +

4

4

GA

Co

nfi

Horizontal Vertical
Interpolation Displays average of 4 corner dotsnti
alOriginal Image

The color of the dot in the upper left
corner of each area is used in thedots of the entire area.

MosaicFigure 3.32 Interpolation, Shading, Mosaic Functions

Interpolation FunctionSE

The MPEG play image is a maximum 352 X 240 dots horizontally, while verticalinterpolation can be displayed at a resolution of a maximum 704 X 480 dots to provide a smooth display with less flickering.
Shading Function

Displays a color data average of four dots that adjoin horizontally and vertically, andcan produce a distant background shading effect.

Saturn Overview Manual47

Mosaic Functionntial

The MPEG play image is divided horizontally, vertically, and at a designated size.
The color of the dot in the upper left of each area indicates the color of all dots inthat area. Horizontal and vertical can be independently designated up to a fullscreen size.
Fade FunctiondeThis is a display function that gives magnification to the coloring signal and screen
brightness, and is used for fade-in and fade-out. Because this isn’t a method of
adding and subtracting offset values, only the brightness can be correctly changed.
Further, by changing the coloring signal, the monochrome display or displayedcolor can be deepened.
Chroma KeyBlue Background

Sprite Screen

Co

MPEG Screennfi

As shown in Figure 3.33, this function plays animation that has transparent dots.
The chroma key is a technique of filming an object in front of a blue background,taking out all parts that are not blue, then placing those parts in a separate picture.
MPEG animated images can be used only on background with the existing MPEG
LSI, but the chroma key function lets Saturn superimpose and display MPEG animated images on sprite and scrolls.

SE

GA

TV Screen48

Figure 3.33 Chroma Key Function

Scroll ScreenScreen Retrieve FunctionntialAnimated images played by MPEG are retrieved to the main system by this function, and are handled as sprites, used as texture data, and displayed using the VDP1and VDP2 functions. Furthermore, this function playing of multiple animations.
The amount of MPEG animated data is 50 times the amount of data from a CD, andbecause the transfer speed is faster than the transfer speed from a CD buffer, thisfunction can be used to rewrite texture data at high-speeds.
High Detail Pause Function

Pause Function, Freeze FunctiondeThis function displays a 704 x 480 dot high detail pause screen. Full color high detail
images cannot be displayed by the main system (full color is up to 352 x 240 dots),
but if the high detail pause function is used, an image with Saturn’s maximum
number of color can be displayed.

nfi

The pause function can pause the animation at any frame, and can run in slow
motion as well as frame by frame.
The freeze function memorizes animation at any frame (image memory) and allows
strobe playback.
Branch Play Function

Co

MPEG accumulates compressed image data in the CD buffer memory and plays
animation during CD seek (track search). As a result, animation will continue playing even when jumping to another animation track. The screen will not pause aswith LD.

SEGA

In MPEG, the branch playback where branch point cannot be determined isachieved. Furthermore, loop play, which repeats the same animation, can be done.

Saturn Overview Manual49

MPEG / Audio Function

ntialAudio data played by MPEG/Audio is sent to the SCSP by the same path as a CDDA (Music CD), and can perform various effects.
Variable Compression Rate

The compression rate can be selected in response to the use; you can choose from acompression of 1/3.5 ~ 1/21. If the 1/21 compression is used, 50 hours of audio canbe recorded on a CD. Even with huge RPG and ADV, all dialogue and narration canbe performed with audio.
On Memory Play Function

Corresponding Standards

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MPEG / Audio can compress to 1/3.5 ~ 1/21. When using half of the
4 Mbit of CD buffer memory for MPEG/Audio by using a compression of 1/21, 64
seconds of audio can be played without accessing the CD. As a result, audio playcan be done without waiting. Furthermore, several short dialogues can be connected for long conversations.

Table 3.12 shows the standards that correspond to the CD-ROM system.
Table 3.12 Corresponding Standards

Description

CD-DA

The standard name of sound entered on a CD is base on the REDBOOK
international standard. Sampling frequency 44.1 KHz, quantumization bit
16-bit stereo.

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Standard

CD-G, CDEG Records data such as graphics data in the music CD format area.
Employs 16 color display and CD-DA sound quality.

CD-ROM

The standard has been established to enable recording of computer datawith the same physical format as a music CD (CD-DA). Based on YELLOWBOOK international standard.

CD-ROM XA This is an expanded CD format with a record format that makes possible
EB

GA

interleave recording for concurrent playing of video and audio.

CD-ROM software record format that is employed by the Sony Data Discma(electronic book) (electronic book player).

Photo-CD

System that displays photographs through a monitor such as a television.
Up to 100 photographs can be recorded on a CD; the same photograph ca
be enlarged and reduced.

Video CD
Records video that has been compressed by MPEG. A maximum of 74(Karaoke CD) minutes can be recorded on a CD, and a maximum of 2000 high detail pau

SEpictures can be played.

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3.7

Other Items

nti
al

SMPC

SMPC resets the entire Saturn system when the reset button is pressed or the power
turned on. The command from SH-2 turns on or off the peripheral LSI inside of
Saturn, sets and retrieves the calendar and time, and collects data from peripherals.
The clock change command switches between a horizontal resolution of 320 or 352
dots.

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Inside Saturn

MC68EC000

reset
data
command

SMPC

clock switch

Reset Switch

Sound Reset
System Resetnfi

Power On Reset

VDP1

SCU

RES

NMI

SH-2
(master)

SCSP

NMI

SH-2
(slave)

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PLL

RES

VDP2

*Switch

PAD(* Peripheral I/O terminal can be directly controlled from the SH-2 side.)SE

GA

Figure 3.34 SMPC System Configuration

Saturn Overview Manual51

Functionsntial

The main functions of SMPC are shown in Table 3.13.
Table 3.13 SMPC Functions(Real Time Clock)SM(System Management)

PC• ON/OFF of Sound CPU• ON/OFF of master SH-2 and slave SH-2
• Controls system reset• Switches clocks (PLL switch)• Power ON reset• When Saturn is ON, Saturn system is reset bypressing thereset switch.
• Automatically collects peripheral data such ascontrol pad
and mouse.
• Supports Megadrive and Genesis peripherals (3button, 6 button, 4 player adapter, mouse).

nfi(Peripheral Control)• Sets and retrieves time and date form SH-2
• Battery back-up function• Automatically revises the date, day of the week,hour/minutes/seconds.

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RTC

PAD

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Table 3.14 shows the digital PAD specifications for Saturn.
Table 3.14 Saturn Digital PAD Specifications
PAD Type

Buttons: up, down, left, right, A, B, C, X, Y, Z, L, R, start.

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Saturn Standard PAD

Specifications

52

nti
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INDEX
B
Bit map format 33
Branch play function

49

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C3 iii
Cartridge I/F 9
CD-ROM 42
CD-ROM drive 10
CD-ROM drive specifications 43
CD-ROM system data flow 44
CD-ROM system configuration 42
CD-ROM system specifications 42
Cell format 32
Cell format scroll screen 33
Chroma key function 48
Clipping v, 25
Color bank method 22
Color calculation function 35
Color look-up table 22
Color offset function 37
Color operation 23
Compression rate variation 50
Configuration of Color bank method 22
Corresponding standards 50
CPU 6, 11
CPU specifications 11

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C

D

E

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D/A converter 10
Determining priority 34
Display (VDP1) 21
Double density interlace 21
DSP iii

Effect 40
Effect Data v
Encode9F

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Fade function 48
Regular sprite 19
Frame buffer 26
Freeze function 49
Functions (CD-ROM) 44
Functions (SCSP) 38
Functions (SCU) 15
Functions (VDP1) 18
Functions (VDP2) 29

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Giii, 23, 24

ntialGouraud shading

H
Hardware specifications <main system> 6
Hardware specifications <sub system> 6
High detail pause function 49
High Resolution iv

LLine 21
Line and texture parts 21
Line color screen insert 35, 36
Line scroll function 30

M

N

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Enlarge/Reduce function (VDP2) 30
Enlarge/Reduce Sprite (VDP1) 19
MC68EC000 8
Mesh process 24
Mosaic function 30, 48
Mosaic pattern
31
MPEG/Audio function 50
MPEG/Video function 46
MPEG functions 46
MPEG iv, 10

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Image change by image axis 32
Image change by rotation axis 31
Image change by screen axis 32
Interlace iii, 21
Interpolation function 47
Interpolation, Shading, Mosaic Functions 47
Interrupt control (SUC) 15
IPL v

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I

Normal line window 33
Normal rectangular window

O

33

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On memory play function 50
Operating frequency (SCU) 15

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P

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PAD 52PAD I/F 9
PAL format v
Parallel processing 45
Parts classification 18
Parts
iv
Perspective iv
Pause function 49
PCM iv
Pixel iii
PLL v
Polygon 21
Polyline 21
Priority function 34

RAM 6, 8
Related manuals ii
Reverb v
RGB code generation 6, 8
Rotation calculation 32
Rotation display 31
Rotation function 31

S

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R

32

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Saturn digital PAD specifications 52
Screen retrieve function 49
Scroll function 29
Scroll screen 29
Scroll screen configuration 32
Scroll screen function 30
Scroll, Priority functions 29
SCSP 9, 38
SCSP system configuration 38
SCSP system specifications 39
SH-2 8
Shading calculation function 36, 37
Shading function 47
Shadow function 36
Simultaneous display by screen division
Single density interlace 21
SMPC 8, 12, 51
SMPC functions 52
SMPC system specifications 51
Special priority function 34
Sprite iv
Sprite window 33
Stream select mechanism 45
Stream selection 45
System clipping 25
System configuration (CD-ROM) 42
System configuration (SCSP) 38

Saturn Overview Manual55

System configuration (VDP2)
System configuration 7
System specifications (SCSP)

27

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38

T
Texture mapping iv
Texture part 19
Transformed sprite
20
Tunnel and BGM reverb 40
Types of color calculation 23

U
25

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User clipping

V
16
17
27
28

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VDP1 9, 16
VDP1 system configuration
VDP1 system specifications
VDP2 9, 27
VDP2 system configuration
VDP2 system specifications
Vertical scroll function 30

W
46

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Window 33, 34
Window function

56