Mega Drive Documentation
Overall System Documentation
| Date/Code | Document | Author | Description |
|---|---|---|---|
| 1992-02-24 (Sega Ozisoft) | Genesis Software Manual | Sega | This manual contains overall information how to develop for the Sega Mega Drive. It gives an overview of the Mega Drive hardware, describes the memory map, gives detailed information on the VDP graphics chip, I/O and Z80 control. The “Genesis Sound Software Manual” was originally included with this manual, as well as the “Genesis Software Development Manual (Complement)”, which have been separated out here. This manual was the main resource provided to assist developers. It should be noted, this manual contains some information which is known to be incorrect. Additionally many details are omitted, such as various VDP settings, and much information on the YM2612 sound device. Although it is a very useful resource, it must be supplemented with other materials rather than relied upon by itself. Also note that despite the name “Genesis” in the title, this manual was the official programming manual made available to all English-speaking regions, most likely translated by Sega of America from original documentation provided by Sega of Japan. A Japanese version of this manual hasn’t been located, but would have existed. Alternate VersionsGenesis Software Manual - [1992-02-24] (The Code Monkeys) (Partial)High quality scan of a portion of the manual, branded with “The Code Monkeys” watermark. This was useful when the Rex Sabio scans were the only complete manual, but the Sega Ozisoft scans are better quality. Genesis Software Manual - [1992-02-24] (Rex Sabio) The first scans of this document which were openly shared online, branded with “Rex Sabio” watermark. It is lower quality than newer scans, and lacks OCR and thumbnails. It does however have some hand-written notes and corrections to the documentation. Genesis Software Manual (Transcription - Fixed SEGA2.DOC) This is a fixed version of the corrupted SEGA2.DOC file, converted to a newer Microsoft Word format which can be more easily opened in new versions. Genesis Software Manual (Transcription - Corrupted SEGA2.DOC) The original document that circulated the community, circa 1995. This is a partial transcription of the manual, stored in a Microsoft Word 2 document. The file itself has corruption affecting several pages in the sound section of the manual. See above for a fixed version. |
| 1992-02-21 (Sega Ozisoft) | Genesis Sound Software Manual | Sega | A basic overview of sound hardware in the Sega Mega Drive. Despite being the primary official resource on the Mega Drive sound hardware, this manual lacks many details necessary to properly use the sound hardware on the Mega Drive. The manual itself states as much with this note in the index: “This manual explains memory mapping and way of accessing especially. FM sound generation and PSG are explained in another manual.” This other manual referred to has not been located to date. Other documentation on the YM2612 and PSG (SN76489) must be referred to in order to properly understand the hardware. Alternate VersionsGenesis Sound Software Manual - [1992-02-21] (Rex Sabio)Genesis Sound Software Manual - [1992-02-21] (The Code Monkeys) Also refer to alternate versions of the “Genesis Software Manual” to see some versions that include the Sound Software Manual. |
| Version 2.0 1991-07-09 (Sega Ozisoft) | Genesis Software Development Manual (Complement) | Sega | This manual provides more specific information on certain aspects of Mega Drive development, including bootstrapping an initial program, specific information on how to use joypads and various peripheral devices, some advice on known issues and how to handle them, guidance for PAL systems, and some other matters. |
| (Sega Ozisoft) | Genesis Software Manual Addendum | Sega | A brief set of four addendums to the Genesis Software Manual. This document was most likely included with one of the Genesis Technical Bulletins, but that is currently unclear. All the content in this set of addendums is more comprehensively covered in the “Genesis Software Development Manual (Complement)” manual, except for notes 1 and 2 in addendum 4, which are only mentioned in this document.Alternate VersionsGenesis Software Manual Addendum - (Rex Sabio) |
| (Sega Ozisoft) | Genesis Software Manual Corrections | Sega | An apparently unnamed document consisting of four corrections and appendices to the Genesis Software Manual. This document was most likely included with one of the Genesis Technical Bulletins, but that is currently unclear. All the content in this document is more comprehensively covered in the “Genesis Software Development Manual (Complement)” manual or the related technical bulletins.Alternate VersionsGenesis Software Manual Corrections - (Rex Sabio) |
| Genesis Technical Bulletins | Sega | These technical bulletins were issued by Sega of America to registered developers, giving information on a variety of matters related to Mega Drive development. Genesis Technical Bulletin #0 - Genesis Technical Bulletins - [1991-03-13] (Rex Sabio) Genesis Technical Bulletin #1 - Errors within the Microtec examples - [1991-03-13] (Sega Ozisoft) Genesis Technical Bulletin #2 - Genesis Loader Board - [1990-06-19] (Sega Ozisoft) Genesis Technical Bulletin #3 - Z80 Bus Access Precautions - [1990-08-02] (Sega Ozisoft) Genesis Technical Bulletin #4 - Reading the controller pads - [1990-09-07] (Sega Ozisoft) Genesis Technical Bulletin #5 - Cartridge identification - [1990-11-26] (Sega Ozisoft) Genesis Technical Bulletin #6 - Impossible values read from the controller pads - [1991-04-02] (Rex Sabio) Genesis Technical Bulletin #11 - Problems during sound access - [1991-09-09] (Sega Ozisoft) Genesis Technical Bulletin #12 - Problems with repeated resets - [1991-09-09] (Sega Ozisoft) Genesis Technical Bulletin #13 - Corrections to the Genesis software manual - [1991-09-09] (Sega Ozisoft) Genesis Technical Bulletin #14 - ROM Splitting - [1991-09-05] (Sega Ozisoft) Genesis Technical Bulletin #15 - Wait during VRAM READ & Super Target IC19 - [1993-04-05] (Sega Ozisoft) Genesis Technical Bulletin #16 - New Peripherals - [1993-04-05] (Sega Ozisoft) Genesis Technical Bulletin #17 - EPROMs for development boards - [1993-05-25] (Sega Ozisoft) Genesis Technical Bulletin #18 - Lockout code - [1993-05-28] (Sega Ozisoft) Genesis Technical Bulletin #19 - Non-US game requirements - [1993-07-06] (Sega Ozisoft) Genesis Technical Bulletin #20 - Games larger than 16Mb - [1993-07-08] (Sega Ozisoft) Genesis Technical Bulletin #27 - Genesis peripheral devices - [1994-01-24] (Rex Sabio) Genesis Technical Bulletin #28 - IO port usage in header - [1994-01-31] (Rex Sabio) Genesis Technical Bulletin #29 - Genesis Sound Software Manual Correction - [1994-03-10] (Rex Sabio) Genesis Technical Bulletin #29A - Genesis Sound Software Manual Correction (Clarification) - [1994-04-11] (Rex Sabio) Genesis Technical Bulletin #31 - Genesis ID table update - [1994-11-22] (Rex Sabio) Genesis Technical Bulletin #32 - Getting Games Ready For XBAND - [1995-01-30] (Rex Sabio) Alternate VersionsGenesis Technical Bulletin #1 - Errors within the Microtec examples - [1991-03-13] (Rex Sabio)Genesis Technical Bulletin #1 - Errors within the Microtec examples - [1991-03-13] (The Code Monkeys) Genesis Technical Bulletin #2 - Genesis Loader Board - [1990-06-19] (Rex Sabio) Genesis Technical Bulletin #2 - Genesis Loader Board - [1990-06-19] (The Code Monkeys) Genesis Technical Bulletin #3 - Z80 Bus Access Precautions - [1990-08-02] (Rex Sabio) Genesis Technical Bulletin #3 - Z80 Bus Access Precautions - [1990-08-02] (The Code Monkeys) Genesis Technical Bulletin #4 - Reading the controller pads - [1990-09-07] (Rex Sabio) Genesis Technical Bulletin #5 - Cartridge identification - [1990-11-26] (Rex Sabio) Genesis Technical Bulletin #11 - Problems during sound access - [1991-09-09] (Rex Sabio) Genesis Technical Bulletin #12 - Problems with repeated resets - [1991-09-09] (Rex Sabio) Genesis Technical Bulletin #13 - Corrections to the Genesis software manual - [1991-09-09] (Rex Sabio) Genesis Technical Bulletin #14 - ROM Splitting - [1991-09-05] (Rex Sabio) Mega Drive Technical Memo #4 - [1993-02-09] (Rex Sabio) - Equivalent to Technical Bulletin #15 |
Hardware Tools Documentation
| Date/Code | Document | Author | Description |
|---|---|---|---|
| 1991-06-14 (Sega Ozisoft) | Genesis Development Tools Overview | Sega | Gives an overview of the development hardware that was available to external companies wanting to develop games for the Mega Drive. The “Super Mega Drive Manual”, “Mega Drive Loader Handling Manual”, and “Super Mega Drive Manual Supplement” were originally included along with this document, but have been separated out here. |
| 1989-10-16 (Sega Ozisoft) | Mega Drive Loader Handling Manual Ver 4.0 | Sega | The Mega Drive Loader is a parallel interface board which connects to a Mega Drive control port, allowing the transfer of data. More information is given in the Devlopment Hardware section. |
| 1991-01-29 (Sega Ozisoft) | Super Mega Drive Manual | Sega | The Super Mega Drive is an early development system for the Mega Drive. More information is given in the Devlopment Hardware section.Alternate VersionsSuper Mega Drive Manual - [1991-01-29] (The Code Monkeys) |
| 1993-08-02 (Sega Ozisoft) | Super Mega Drive Manual Supplement | Sega | A small supplement to the Super Mega Drive Manual, in the form of faxed photocopies of partially translated extracts from the Japanese version of the manual, which has to date not been located. The majority of this document consists of corrections for pages in the Super Mega Drive Manual. Despite being faxed in 1993, the manual dated 1991-01-29 seems to have already incorporated the majority of the changes.Alternate VersionsSuper Mega Drive Manual Supplement - [1993-08-02] (The Code Monkeys) |
Procedures, Standards, and Miscellaneous Documentation
| Date/Code | Document | Author | Description |
|---|---|---|---|
| 1991-03-01 (Rex Sabio) | Sega Software Development and Game Standards | Sega | |
| 1993-05-14 | Software Production Specifications for Mega Drive 6-Button Control Pad | Sega |
MegaCD Documentation
Overall System Documentation
| Date/Code | Document | Author | Description |
|---|---|---|---|
| Version 1.0 1991-12-13 (Sega Ozisoft) | Mega-CD Outline | Sega | This document provides a basic overview of the MegaCD hardware, with brief descriptions of its major features and components. Unfortunately this document is taken from a faxed copy of the original, so the image quality is degraded and shaded areas are very difficult to read. Alternate versions with different watermarks are still from the same faxed version, so this was apparently used as a master.Alternate VersionsMega-CD Outline - Ver 1.0 [1991-12-13] (The Code Monkeys)High quality scan of the manual, branded with “The Code Monkeys” watermark. This was useful when the Rex Sabio scans were the only complete manual, but the Sega Ozisoft scans are better quality. Mega-CD Outline - Ver 1.0 [1991-12-13] (Rex Sabio) The first scans of this document which were openly shared online, branded with “Rex Sabio” watermark. It is lower quality than newer scans. |
| Version 1.0 1991-10-14 (Sega Ozisoft and Sphere Inc) | Mega-CD Hardware Manual - The Hardware | Sega | Detailed manual covering the hardware design and physical registers. Unfortunately like several other MegaCD manuals this document is taken from a faxed copy of the original, so the image quality is degraded and the frequent shaded areas are very difficult to read. Fortunately for this manual, a partial scan from the “Sphere Inc” version has been located, which was not taken from this faxed master but comes from the original document. Pages from the Sphere Inc version have been used where available, which makes the shaded regions easily readable, with the “Sega Ozisoft” scans filling in the remaining pages.Alternate VersionsMega-CD Hardware Manual - The Hardware - Ver 1.0 [1991-10-14] (Sphere Inc) (Partial)High quality scan of only some of the manual, branded with “Sphere Inc” watermark. This version is not based on the faxed master, and is very readable. Unfortunately the origins of these scans are unknown, so it’s unclear if the entire manual could be scanned, or if these are the only pages that are available. Mega-CD Hardware Manual - The Hardware - Ver 1.0 [1991-10-14] (Sega Ozisoft) High quality scans with the “Sega Ozisoft” watermark, based off the faxed master. Mega-CD Hardware Manual - The Hardware - Ver 1.0 [1991-10-14] (The Code Monkeys) Good quality scans with “The Code Monkeys” watermark, based off the faxed master. Mega-CD Hardware Manual - The Hardware - Ver 1.0 [1991-10-14] (Rex Sabio) The first scans of this document which were openly shared online, branded with “Rex Sabio” watermark. It is lower quality than newer scans. |
| Version 1.0 1991-10-14 (Sega Ozisoft) | Mega-CD Hardware Manual - PCM Sound Source | Sega | Detailed manual covering the MegaCD sound hardware. Unfortunately like several other MegaCD manuals this document is taken from a faxed copy of the original, so the image quality is degraded. Fortunately there are no shaded areas in this document, so it is fairly legible even though the quality is poor.Alternate VersionsMega-CD Hardware Manual - PCM Sound Source - Ver 1.0 [1991-10-14] (The Code Monkeys)High quality scan of the manual, branded with “The Code Monkeys” watermark. This was useful when the Rex Sabio scans were the only complete manual, but the Sega Ozisoft scans are better quality. Mega-CD Hardware Manual - PCM Sound Source - Ver 1.0 [1991-10-14] (Rex Sabio) The first scans of this document which were openly shared online, branded with “Rex Sabio” watermark. It is lower quality than newer scans. |
| Version 0.10 1991-03-06 (Sega Ozisoft) | Mega-CD Software Development Manual | Sega | Essentially a simplified version of “Mega-CD Hardware Manual - The Hardware”. Well worth cross referencing however, as this version is not taken from a faxed copy, so detail that is hard to read in the other manual is easy to read in this one. Generally speaking however, the information in the hardware manual seems more detailed and accurate.Alternate VersionsMega-CD Software Development Manual - Ver 0.10 [1991-03-06] (The Code Monkeys)High quality scan of the manual, branded with “The Code Monkeys” watermark. This was useful when the Rex Sabio scans were the only complete manual, but the Sega Ozisoft scans are better quality. Mega-CD Software Development Manual - Ver 0.10 [1991-03-06] (Rex Sabio) The first scans of this document which were openly shared online, branded with “Rex Sabio” watermark. It is lower quality than newer scans. |
| Version 2.0 1992-02-24 (Sega Ozisoft) | Mega-CD Disc Format Specifications | Sega | Precise technical information on how to encode data onto a CD for use on the MegaCD hardware. This includes detail on the sector offsets for the initial programs, and required header data to include in the volume descriptor of the CD.Alternate VersionsMega-CD Disc Format Specifications - Ver 2.0 [1992-02-24] (The Code Monkeys)High quality scan of the manual, branded with “The Code Monkeys” watermark. This was useful when the Rex Sabio scans were the only complete manual, but the Sega Ozisoft scans are better quality. Mega-CD Disc Format Specifications - Ver 2.0 [1992-02-24] (Rex Sabio) The first scans of this document which were openly shared online, branded with “Rex Sabio” watermark. It is lower quality than newer scans. |
| Version 2.0 1992-02-24 (Sega Ozisoft) | Mega-CD Bios Manual | Sega | Details on the MegaCD BIOS, and the various routines exposed by the BIOS to programs running on the MegaCD hardware.Alternate VersionsMega-CD Bios Manual - Ver 2.0 [1992-02-24] (The Code Monkeys)High quality scan of the manual, branded with “The Code Monkeys” watermark. This was useful when the Rex Sabio scans were the only complete manual, but the Sega Ozisoft scans are better quality. Mega-CD Bios Manual - Ver 2.0 [1992-02-24] (Rex Sabio) The first scans of this document which were openly shared online, branded with “Rex Sabio” watermark. It is lower quality than newer scans. |
| Sanyo LC7883 Datasheet | Sanyo | Datasheet for the Sanyo LC7883 D/A converter used in the MegaCD. This datasheet was included in the documentation pack sent to MegaCD developers, and was watermarked by Sega with the company name like other Sega documentation.Alternate VersionsSanyo LC7883 Datasheet - (The Code Monkeys)High quality scan of the manual, branded with “The Code Monkeys” watermark. |
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| Sanyo LC8950 & LC8951 Design Manual | Sanyo | Critically important manual from Sanyo detailing the workings of the low-level LC8950 CD decoder chip, which is directly controlled by the MegaCD bios. With over 100 pages of content, this manual is unusually detailed and provides a thorough description of this device. Although developers creating games for the MegaCD would not have generally needed this level of detail at what was a lower level of the hardware, the information in this manual is extremely important for emulation purposes today.Alternate VersionsSanyo LC8950 & LC8951 Design Manual - (The Code Monkeys)High quality scan of the manual, branded with “The Code Monkeys” watermark. Sanyo LC8950 & LC8951 Design Manual - (NW Synergistic) High quality scan of unknown origin, branded with “NW Synergistic” watermark. This scan is missing the title page and contents. |
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| 1993-01-12 (Sega Ozisoft) | Mega-CD Software Supplement Materials | Sega | A lengthy document containing corrections and additions to information in the original software manuals, as well as additional information and guidance on a variety of issues. This manual was included in Mega-CD Technical Bulletin #3. |
| MegaCD Technical Bulletins | Sega | These technical bulletins were issued by Sega of America to registered developers, giving information on a variety of matters related to MegaCD development. Sega-CD Tech Bulletin - The US Bios - [1992-06-16] (Sega Ozisoft) Sega-CD Tech Bulletin - PAL Conversions - [1993-02-09] (Sega Ozisoft) Mega-CD Technical Bulletin #1 - Corrections and updates to MegaCD manual - [1992-12-08] (Sega Ozisoft) Mega-CD Technical Bulletin #2 - Backup RAM - [1993-02-10] (Sega Ozisoft) Mega-CD Technical Bulletin #3 - Mega-CD Software Supplement Materials - [1993-02-10] (Sega Ozisoft) Mega-CD Technical Bulletin #4 - Sega-CD PCM sound chip playback frequency - [1993-03-15] (Sega Ozisoft) Mega-CD Technical Bulletin #5 - Wait during VRAM READ & Super Target IC19 - [1993-04-05] (Sega Ozisoft) Mega-CD Technical Bulletin #6 - Macintosh Sound Designer problems - [1993-04-21] (Sega Ozisoft) Mega-CD Technical Bulletin #7 - New standards for Sega-CD ID table - [1993-06-08] (Sega Ozisoft) Mega-CD Technical Bulletin #8 - Mega-CD II Changes - [1993-06-21] (Sega Ozisoft) Mega-CD Technical Bulletin #9 - Non-US market games requirements - [1993-07-06] (Sega Ozisoft) Sega-CD Technical Bulletin #16 (Missing) - Additional cd software development guidelines as well as updates to the CD-ROM Manual Sega-CD Technical Bulletin #17 (Missing) - Contains info of sega approved write-once writers and discs Sega-CD Technical Bulletin #18 (Missing) - Swapping PRG-RAM (program RAM) into the Genesis side by halting the SUB CPU the method is unsafe and unstable Sega-CD Technical Bulletin #19 - Interupt level 5 - [1994-03-03] (Rex Sabio) Sega-CD Technical Bulletin #20 - CD Writing Equipment and Software for Sega-CD - [1994-11-09] (Rex Sabio) Cinepak Technical Bulletin #1 - Cinepak Version 1.2 - [1994-06-24] (Rex Sabio) Cinepak Technical Bulletin #2 - Cinepak Long Movie Bug - [1994-07-01] (Rex Sabio) |
Hardware Tools Documentation
| Date/Code | Document | Author | Description |
|---|---|---|---|
| Version 1.0 1993-05 (The Code Monkeys) | SNASM-CD Installation Manual | Sega | Hardware setup information for the original Cross Products SNASM-CD development system. The information here is for the original SNASM release, not the updated SNASM2 version. This manual is included here as it is released by Sega, but more detailed manuals on the SNASM2 version of the system are provided in the development hardware section.Alternate VersionsSNASM-CD Installation Manual - Ver 1.0 [1993-05] (The Code Monkeys) (Alt) - Another scan of the same manual, which is believed to have originated from the same company (The Code Monkeys). Despite the identical origins though, it is believed this was a separate physical copy. |
Procedures, Standards, and Miscellaneous Documentation
| Date/Code | Document | Author | Description |
|---|---|---|---|
| 1992-05-06 (Sega Ozisoft) | Sega-CD Software Standards | Sega | A set of guidelines and requirements which games needed to follow in order to be certified for release by Sega.Alternate VersionsSega-CD Software Standards - [1992-05-06] (The Code Monkeys)High quality scan of the manual, branded with “The Code Monkeys” watermark. |
| 1992-05-03 (Sega Ozisoft) | Mega-CD User Interface | Sega | Initial design details of the MegaCD BIOS user interface for the US market.Alternate VersionsMega-CD User Interface - [1992-05-03] (The Code Monkeys)High quality scan of the manual, branded with “The Code Monkeys” watermark. |
| 1994-06-20 | Mega CD/Sega CD Release/Checklist Forms (Missing) | Sega | Referenced in MegaCD Technical bulletin #20. These forms are known to exist and be in the possession of a collector, but have not yet been scanned or made available online. |
32x Documentation
Overall System Documentation
Hardware Tools Documentation
| Date/Code | Document | Author | Description |
|---|---|---|---|
| MAR-45-081594 (Elliot Gay) | 32X Development Equipment and Materials Menu | Sega | Alternate Versions32X Development Equipment and Materials Menu - [MAR-45-081594] (Rex Sabio)The first scans of this document which were openly shared online, branded with “Rex Sabio” watermark. It is lower quality than newer scans. |
| MAR-46-081594 (Rex Sabio) | IC BD 32M SRAM + 256K BUP 32X 837-11068 User’s Manual | Sega | |
| MAR-47-081594 (Rex Sabio) | IC BD 4M 32 PIN * 8 EPROM 32X 837-11069 User’s Manual | Sega | |
| MAR-48-081594 (Rex Sabio) | IC BD 16M 42 PIN x 4 EPROM 32X 837-11070 User’s Manual | Sega | |
| MAR-57-102894 (Sega Ozisoft) | Mega Drive & 32X Address Checker Specification | Sega |
Software Tools Documentation
| Date/Code | Document | Author | Description |
|---|---|---|---|
| MAR-40-072094 (Elliot Gay) | 32X Sample Disk | Sega | Alternate Versions32X Sample Disk - [MAR-40-072094] (Rex Sabio)The first scans of this document which were openly shared online, branded with “Rex Sabio” watermark. It is lower quality than newer scans. |
| MAR-61-A-040695 (Rex Sabio) | 32X Sound Tool Package | Sega | |
| MAR-61-B-040695 (Rex Sabio) | Tone Editor 32X - Ver 1.00 | Sega | |
| MAR-61-C-040695 (Rex Sabio) | MIDI Converter - Ver 1.30 | Sega | |
| MAR-61-D-040695 (Rex Sabio) | 32X Sound Simulator - Ver 1.00 | Sega | |
| MAR-61-F-040695 (Rex Sabio) | PWM Driver - Ver 1.06 | Sega | |
| MAR-61-E-040695 (Rex Sabio) | 68000 Sound Driver - Ver 3.00 | Sega | |
| MAR-63-090894 | Map Editor 32X User’s Manual | Sega | Unlike most other 32X documents here, this document comes from a digital version rather than a scan of a physical copy, which was included in the combined “Saturn Graphics Tools Manual” in the March 1996 DTS CD, under “DOCUMENT\SATURN\GRAPHICS.PDF”.Alternate VersionsMap Editor 32X User’s Manual - [MAR-63-090894] (Elliot Gay) - A high quality scan of the manual. Since a digital version of the manual has been located, that is preferred over this version. |