Yamaha SRE-01
This page was last modified 02:28, 17 December 2021 by Mars2000you. Based on work by Gdx and Msxholder and others.



The module SRE-01 is an expansion of 32kB RAM combined with an slotexpander. This module was manufactured and sold by Yamaha. Product name is 32K RAM/Expansion Slot Unit.

It is only for a Yamaha or derivative computer (Victor, Sakhr) with 60 pin expansion slot, It's actually the slot 3 that is therefore expanded: slot 3-1 becomes an extra cartridge slot and slot 3-0 hosts the extra RAM. As such it cannot be used with computers that already have an expanded slot 3.

On one side you have the 60 pin connector, on the other side an Expansion Slot Unit with a normal MSX 50 pin connector.

The RAM is placed on pages 0 and 1 (0000h~7FFFh) in slot 3-0. As such it is only useful to upgrade a 32kB MSX to 64kB. However the systems base memory and the expansion will be in different slots which can cause compatibility problems with some software that blindly assumes all memory to be in a single slot.

If you are looking for a memory expansion we recommend to buy another standard expansion. A 64kB RAM expansion, or even better a Memory Mapper cartridge that initializes its segments itself at start up is the best choice.

Systems with which the SRE-01 should work:

Launch price was ¥12,800

SRE-01 Slot Map (inserted in slot 3)

Slot 3-0 Slot 3-1 Slot 3-2 Slot 3-3
Page C000h~FFFFh Cartridge
Slot 2 or 3 (*)
Page 8000h~BFFFh
Page 4000h~7FFFh 32kB RAM
Page 0000h~3FFFh

(*) 3 when the computer has already 2 cartridge slots - 2 or 3 when the computer has only 1 cartridge slot, according you use the eventual expansion bus as cartridge slot (with the Yamaha Single Cartridge Adapter CA-01) or not


Yamaha SRE-01
Yamaha SRE-01 PCB