Visual memory

from Wikipedia, the free encyclopedia
Sega Dreamcast VM

The VM ( Visual Memory ) is actually a memory card for the game console Dreamcast of Sega . In contrast to other memory cards, it not only serves as a memory card, but can also be used as an additional display in the gamepad or even as a stand-alone handheld .


  • Connections: 2 × 7 contact pins on the top with a serial interface
  • Main processor : 8-bit sub-clock: 32 kHz, RC-clock: 600 kHz Main-clock: 6 MHz (Sanyo LC8670 "Potato"), a processor specially made for Sega, which is largely compatible with the Sanyo LC86104C
  • Memory: 128 KB flash memory , of which 24 KB as read-only memory (ROM) and 1 KB as main memory (RAM); For data storage, e.g. for savegames , 100 KB are available to the user, divided into 200 blocks, or 64 KB / 128 blocks thereof for the execution of independent VM application programs. These are mostly small mini-games. There are another 41 blocks on each VM, but you have to activate them manually.
  • Screen: 48 × 32 pixels and four symbols at the bottom of the screen, monochrome 1 bit
  • Screen size: 37mm wide × 26mm high
  • Sound : 1-channel pulse width modulation (PWM)
  • Case size: 47 mm wide × 80 mm high × 16 mm thick (1.85 in × 3.15 in × 0.63 in)
  • Power supply: 2 × CR2032 button cell , switches itself off automatically
  • Weight : 45 g


The interface of the VM can be plugged into the controller of the Dreamcast, but two VMs can also be connected directly to each other in order to play games (e.g. Chao Battle from Sonic Adventure) against each other or to copy memory from one card to the other . The VM can only save one playable game at a time.

Mostly the display was only used for the game logo or for short animations (for example Virtua Tennis 2 ). In some games such as Sonic Shuffle, however, each player had their own screen so that only they could see their cards. Resident Evil used the display for status displays.


After the (commercial) end of Dreamcast there were no further official developments for the VM. However, just like for the Dreamcast itself, there is still a small, active developer scene for the VM.

Web links