The 32K Dynamic RAM Board

Acorn System 32K Dynamic RAM Board

"This Eurocard provides 32768 bytes of Random Access Memory for a computer system. All of the circuitry is on a 100 x 160mm Eurocard which connects to the standard Acorn computer bus, and it is intended for 6502 or 6809 systems.

The 16 dynamic RAM devices are organised as two banks of 16384 by 8 bits.

Timing is generated on the card in synchronism with the 1MHz CPU clock and the hardware transparent-refresh circuitry allows random access of the RAM in any clock cycle.

The RAM is organised into four sections (or two in the 16K-byte option), each of which is 8192 bytes (two blocks) long. These four sections can each be linked to begin at address 0000, 2000, 4000, 6000, 8000, C000, and E000 (hex). In the Acorn systems 2, 3, and 4 the card will usually be used to provide 8K-bytes of program space at C000 to DFFF, and 24K-bytes of text space at 2000 to 7FFF (hex). A second 16K-byte card can then be used to fill the remaining space from 8000 to 4 BFFF (hex) if required. The dynamic RAM cards can be freely mixed with static RAM cards and they can be paged if required."



also see this section from the System 5 Manual System 5 Handbook Part 2 Section 3 32K DRAM Board [2]



 200.010 Issue 3 [0]

Acorn System 32K Dynamic RAM Board PCB Issue 3Acorn System 32K Dynamic RAM Board PCB Issue 3


200.010 Issue 4 [3 System 5]

Acorn System 32K Dynamic RAM Board PCB Issue 4Acorn System 32K Dynamic RAM Board PCB Issue 4


Replica Board:

I have made a replica of this board details of which can be found here:


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