1Mb RAM Expansion
 connects to: CPU Fast Slot (A2000)
Rev 3 card with 512k fitted
Rev 3 card with 1MB fitted
Hi Res version, Front
- 4608 x 3456, 4,596K
Hi Res version, Back
- 4608 x 3456, 4,752K
Max Ram: 1MB
Ram Type: Soldered and Socketed 256x1 DRAM Chips
FPU: None
RTC: None
Connection: A2000 CPU Fast Slot (aka MMU slot on Model-As)

A RAM expansion originally designed for the Rev 4.0 German "Model-A" A2000s. It was designed to be connected to the "MMU slot", which became known as the CPU Fast slot the US designed 'B2000s'. This card may not be compatible with Model B & C A2000s in all configurations.


The description refers to the jumpers labelled left to right, with the pins labels as followed:


 2 4 6 8 10
 | | | | |
 1 3 5 7 9

For 0.5 MB of RAM, the following pins should be connected:
3 & 4
5 & 6
7 & 8

Memory in the lower bank of 16 chips is placed at Address: $C00000-C7FFFF, and is OS-detected.  This is what would be the slow-fast 512K memory range in the 8370/8371 PLCC Agnus Rev 4.x B2000 motherboards, but is actual FastRAM (and not connected to the Agnus-side of the bus).

For 1MB of RAM:
3 & 4
9 & 10

This places the second bank of 512K into $C80000-CFFFFF, on top of the 512K above, for a total of 1MB located at $C00000-CFFFFF.

The above two configurations are compatible with the Rev 4.x/6.x B2000 motherboard only if configured with a 1MB/2MB Agnus in the 1MB/2MB ChipRAM configuration. 

The configurations below should be incompatible with the Rev 4.x/6.x B2000 motherboard as it has Kickstart in ROM, and no boot ROMs.  Presumably the card has a 512K overlay of the ROM.  (This logic/statement is under review as of 3/2023).

For Kickstart RAM:
1 & 2
5 & 6
7 & 8

For Kickstart RAM and 0.5MB RAM:

1 & 2
9 & 10

Testing on a B2000 motherboard indicates the RAM is present behind the ROM image. 

Page contributors: Calum Tsang, Iggy Drougge, Mario Misic, Pascal Lefrancois, RiWa & Friends, Robert Miranda (GVP Tech Support), Steen Jessen
Updated: 3/2/2023 . Added: 12/22/2004