Sega CD

The Sega CD (or Mega-CD) was Sega's answer to the PC Engine CD-ROM² / TurboGrafx-CD System. It had fairly decent third-party support and a strong launch showing in Japan (where the Mega Drive was never in first place)... but between the Super Famicom's popularity in Japan, and Sega of America and Sega Europe's insistence on shoving out FMV games, that success just could not last anywhere. In fact, all those FMV games are what it's mostly remembered for now.

Sub-Pages#

Prototype Info Notes

Semi-Unused Font#

The font used on the Memory Management, Copyright and Region Lockout Screens have some unused characters. This includes lower case letters, square and curly brackets, quotation marks, and other symbols.

Version Differences#

Variant Sega/Mega-CD systems include:

• Sega CD (US)/Mega-CD (Japan, Asia, Europe/Australia) [1991] - The original add-on model for separate Genesis/Mega Drive and Genesis 2 consoles.
• Wondermega (JP) [1992] - An all-in-one Mega Drive and Mega-CD, usually with other extra features. Both Sega and Victor marketed Wondermega models.
• Sega CD 2 (US)/Mega-CD 2 (Japan, Europe/Australia) [1993] - A cost-reduced add-on model for separate Genesis and Genesis 2 consoles, with a totally revised form factor.
• Sega PAC (Japan, US) [1993] - One of several add-on modules for Pioneer's LaserActive LaserDisc player (others include the NEC PAC for the PC Engine family). Allows the system to play not only Genesis and Sega CD games, but also the exclusive "LaserActive Mega LD" format: essentially, a LaserDisc with a similar game program to a Sega CD (these games constitute their own separate platform with a separate software library).
• Wondermega M2 (JP)/X'eye (US) [1993] - An all-in-one Genesis and Sega CD, usually with other extra features. A revised model of the original Wondermega, this time marketed just by Victor. The M2 version was the basis for the X'Eye, marketed in the US by Victor's parent company, JVC.
• CDX (US)/Multi-Mega (EU/AU)/Linguaphone Education Gear (JP) [1994] - An all-in-one Genesis, Sega CD, and portable CD player.
• Aiwa CSD-GM1 (Japan) [1994] - A rare Aiwa portable stereo with a Mega Drive and Mega-CD integrated.

BIOS Versions#

This needs some investigation. Discuss ideas and findings on the talk page. Specifically: See if any of these BIOSes will just load arbitrary code (not check the game region).

There are many, many, many different versions of the Sega CD BIOS, each featuring their own boot screens and UIs, and each running on a different set of Mega Drives.
Bios versions greater than 2.00 can use the Sega Mega Mouse for the controlling of menus.

Note: The Intro Type and UI Type numbering is arbitrary and provided for expository purposes only. They do not represent any sort of official classification or order.

Intro Types#

This page or section needs more videos. There's a whole lotta words or pictures here, but not enough videos. Please fix this. Specifically: Get higher quality videos of some of these.

Note: Different BIOS builds and/or different hardware may feature minor variations on what is otherwise the same intro type, such as changes to version numbering, copyright or labeling changes (e.g. Intro Types 7-A and 7-B).

Intro Type	Screenshot	BIOS Music	Notes
1		01	Typically used by: Japanese and Asian BIOS version 1.x on Mega-CD 1 systems Depicts the Japanese Mega-CD logo animated against a sky backdrop. A replica of this boot screen, complete with music, also appears as a gag in Panic! as scene 12-D. (Footage) The US localization of that game does not change the scene at all, even though no American Sega CD model features this boot screen.
2		02	Typically used by: US BIOS version 1.x on Sega CD 1 systems Depicts the Sega CD and SEGA logos animated against a space backdrop. Neither the first part of the animation, nor the first part of the background music, loop.
3		01	Typically used by: European BIOS version 1.x on Mega-CD 1 systems Depicts the Japanese Mega-CD Logo and the SEGA logo animated against a space backdrop, similar (but not identical) to Intro Type 2.
4		01	Typically used by: Japanese BIOS version 2.x on, e.g., Mega-CD 2 systems Depicts the Japanese Mega-CD 2 logo and the SEGA logo, animated against a backdrop which features some geometric solids and Sonic striking one of his trademark poses. Among the animations are some that move the logos through the layer behind the shapes.
5		03	Typically used by: US BIOS version 2.x on, e.g. Sega CD 2 systems Depicts the Sega CD and SEGA logos animated against the same space backdrop from Intro Type 2. The animations are nearly (if not exactly) identical to those in Intro Type 4, but since the backdrop is different, they may look odd at times.
6		01	Typically used by: European BIOS version 2.x on, e.g. Mega-CD II systems Depicts the Japanese Mega-CD logo1 and the SEGA logo animated against a similar backdrop to Type 4's, the biggest change being the replacement of Sonic with a yellow CD. Unlike Type 4, Type 6's animations keep the logos permanently layered on top of everything in the backdrop and no longer pass them behind the shapes. Otherwise, the animations are nearly (if not entirely) identical to the other versions.
7-A		01-A	Typically used by: Japanese BIOS version 1.x on Sega/Victor Wondermega systems The first of the Wondermega Type 7 variants. Depicts a static Wondermega logo and an animated "W" logo against a spherical torus backdrop (from the Victor model's box art) whose colors cycle through the rainbow. Uses a slight variation of the Mega-CD BIOS music with echo effects added to one of the piano samples, particularly during the second half; this variation is also used in Types 7-B and 8. The two Type 7 intros are identical except for their instruction captions and copyright information. In Type 7-A, they read as follows: Copyright Instruction ©SEGA 1991 Ver 1.00 スタートボタンを押して下さい (Press the Start Button)
7-B		01-A	Typically used by: Japanese BIOS version 2.x on Victor Wondermega M2 systems The second Type 7 variant. identical to Type 7-A in every way, except for the instruction caption and copyright information having been revised as follows: Copyright Instruction ©VICTOR Co./SEGA 1993 Ver 2.00 ディスクチェック中 (Checking Disc) While the BIOS builds used by the Wondermega and Wondermega M2 both use very similar Type 7 variant boot screens, they use entirely different UIs from each other.
8		01-A	Typically used by: US BIOS version 2.x on X'Eye systems Another variant of Intro Type 7, virtually identical to the others apart from a) the obvious replacement of all the Wondermega branding with JVC and X'Eye branding, and b) the removal of a few animations. The X'Eye's BIOS otherwise shares its UI with the Wondermega M2.
9-A		N/A	Typically used by: US BIOS version 0.98–1.x on the Sega PAC add-on for LaserActive The Sega PAC uses a barebones menu with Pioneer branding and copyright information. The screen has some animation: a large LaserActive logo zooming into the screen and stopping once it gets close, accompanied with a little descending whoosh sound and rotating Sega CD and Mega LD logos. Sega PAC BIOSes are normally broken on emulators and regular Sega CD systems, although special emulators such as ares and BlastEm have support for them.
9-B		N/A	Typically used by: Japanese BIOS version 0.98–1.x on the Sega PAC add-on for LaserActive Same as previous, except it uses the Mega CD logo instead of the Sega CD one.

UI Types#

Note: Different BIOS builds and/or different hardware may feature minor variations on what is otherwise the same UI type, such as minor design or labelling changes.

UI Type	Screenshot	Notes
1		Typically used by: Japanese, Asian and European BIOS version 1.x on Mega-CD 1 systems and Sega/Victor Wondermega systems; Japanese BIOS version 2.x on Mega-CD 2 systems
2		Typically used by: US BIOS version 1.x on Sega CD 1 systems
3		Typically used by: US and European BIOS version 2.x on Sega/Mega-CD 2 systems
4-A		Typically used by: Japanese BIOS version 2.x on Victor Wondermega M2 systems
4-B		Typically used by: US BIOS version 2.x on JVC X'Eye systems A slight variant of UI Type 4-A which drops both the Pitch button and the "MUSIC" caption along the top of the interface.

Memory Management Menu#

Boot ROMs intended for different models of Sega CD hardware, appropriately enough, change the console's icon in the save data management menu to match their model.
Note: The language used on this screen is either English or Japanese depending on the region of the BIOS, but the icons remain the same regardless of region.

UI Type	Screenshot	Notes
1		Used on Model 1 systems.
2		Used on Model 2 systems and the Aiwa CSD-GM1. (Source: AERGAN)
3		Used on the Victor Wondermega RG-M1
4		Used on the Victor Wondermega RG-M2 and JVC X'Eye. Interesting to note is that the X'Eye uses a different font for English text, while the Wondermega M2 uses the same font for Japanese text as the Model 1, Model 2 and RG-M1 Models. The palette on this screen is also slightly different causing the Backup RAM Cartridge to appear slightly darker.
5		Used on the CDX all in one console.
6		Used on the Pioneer LaserActive. The major differences are that the icon is that of a LaserActive, and the format is MEGA_LD & SEGA_CD instead of SEGA_CD_ROM.

Model 1	Model 2	CDX	WM M1	M2 X'EYE	LaserActive

SEGA Logo#

The Sega CD, much in the vein of the Genesis itself, includes a licensing notice before the start of each game. Japanese and Asian units contain a screen with the SEGA logo against a white background, which fades to black as the SEGA jingle plays and the logo glows. US and European units include an animation of Sonic the Hedgehog shaking his finger, releasing magical sparkles that surround the SEGA logo.

Japan, Asia	US, Europe

Region Lockout#

Some Sega CD Boot ROMs have checks in place to prevent you from mixing and matching different region Sega CDs and Genesis consoles. If the Boot ROM with region locking detects a region mismatch at boot, then it will display a message in black text on a light blue background. This message changes depending on which region of Sega CD you have.

Japan, Asia (NTSC)	US	Europe	Asia (PAL)

Interestingly enough some Boot ROMs that don't region lock consoles (such as the JVC X'Eye's Boot ROM) have the message for the lock out still inside the ROM viewable through a hex editor, though early Boot ROMs such as 1.00g seem to be the exception.

References#