VMU

The VMU (short for Visual Memory Unit, not Virtual Memory Unit) is the "memory card" for the Sega Dreamcast. While its most basic function is as a removable storage device, the VMU has other purposes as well. It can serve as an auxiliary display during normal gameplay (providing maps and H.U.Ds) and, through the use of additional software, it can act as a console independent of the Dreamcast.

In Europe, the VMU was simply called a VM, short for Visual Memory.

Never stop playing

Sega Dreamcast VMU with third-party memory card (left).

Several titles for the Dreamcast included mini-games that could be downloaded onto a VMU. The Sonic Adventure series included a mini-game Chao Adventure (a sort of Tamagotchi clone). Players could load the VMU with chao eggs and newborn chao and playing with them on the VMU, one could increase stats of their Chao on the move and redownload their improved Chao back into the Dreamcast game. Many other games also supported this never stop playing philosophy.

The VMU required two watch-style batteries (Model Number CR-2032), inserted into the rear under a screw-secured lid. The battery type required was the same model of battery as required by the Sega Saturn console for it's internal memory to be saved. Even when the batteries are dead, or no batteries are inserted, the VMU can still be used as a fully functional memory card (game data will not be lost); and the screen will still function when inserted into a Dreamcast control pad.

Connectivity

A VMU would plug into the top of a Dreamcast controller as opposed to plugging into the main console itself. The main reason for this being that a hole within the controller allows the inverted VMU screen to be seen while playing a game. Two VMUs were able to be plugged into each Dreamcast controller, with the frontmost VMU's screen being visible in the centre of the controller. Developers were then able to do whatever they wished with this screen during gameplay such as display maps and individual H.U.Ds during multiplayer games. For example, in the game Sonic Shuffle, each player could privately look at their deck of numbered cards on the VM screen within their controller. This allowed for more tactical play and prevented the player's cards from being displayed on the main television screen. Usually, games simply showed a logo on the VM screen during gameplay; in Sonic Adventure, characters were displayed during the title sequence, and during gameplay a Chao character was displayed. 2 VMUs could also be connected together independently of the Dreamcast console allowing users to swap game saves and also to play multiplayer VMU mini games such as the Chao Battle mode contained within Chao Adventure.

Upon first use of a VMU, the user could assign a simple logo to it. The logos available for selection included skull and crossbones and thunderbolts. The logo was displayed in the VMU screen whilst in the Dreamcast's system menu, and was also displayed on the main screen when selecting a VMU to view. This allowed for easy identification, especially useful if multiple VMUs were inserted into multiple controllers at once.

Dreamcast titles that include VMU games

Sonic Adventure
Skies of Arcadia
Powerstone
Sega GT Homologation Special (Japanese Version)

Technical specifications

• CPU: 8-bit (Sanyo LC8670 "Potato")
• Memory: 128 KB (200 blocks)
• Display: 48 dot width x 32 dot height, monochrome
• Display size (width×height): 37 mm × 26 mm (1.46 in × 1.02 in)
• Case dimensions (width×height×depth): 47 mm × 80 mm × 16 mm (1.85 in × 3.15 in × 0.63 in)
• Power source: 2 x CR2032 batteries with auto-off function
• Sound: 1-channel PWM sound source
• Weight: 45 g (1.6 oz)

See also

• PocketStation
• GameCube-to-GBA cable