"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.
Schematics:
Documentation:
also see this section from the System 5 Manual System 5 Handbook Part 2 Section 3 32K DRAM Board [2]
Photos:
200.010 Issue 3 [0]
200.010 Issue 4 [3 System 5]
Replica Board: