| 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.
Jumpers
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.