Static Memory Systems - 64K RAM/EPROM Board
SMS called this board "The last Memory" board.
THE LAST
MEMORY
was a high performance
64K memory board for
8 bit (only) S-100
systems. This board uses TMM
2016, MB8128, or equivalent static
RAM's. The use of static RAM eliminated the timing and reliability problems
associated with some dynamic RAM
boards (using DMA etc). The 2K by 8 architecture of these RAM's allowed high
density and low power consumption, a characteristic not found
in most static memories up
until that time. THE LAST MEMORY™
also accommodated 2716 type EPROM's in place of the RAM IC's with no
modifications.
Mixing
RAM and EPROM the 2K by
8 static RAM and 2716 EPROM's are pin-for-pin
compatible and could be located at any position on this board.
However, caution had to be exercised when mixing RAMs and 2716a. The RAM's
supplied have an
access time of 150
nsec, allowing full speed operation
with many 6 MHz processors. High speed versions of the 2716 were not
available
and
since
wait
states
are not
generated by the board,
system speed was
limited by the speed of the 2716's
used. If high speed operation was required, the Harris semiconductor HM7617
bipolar PROM could be used in place of the 2716 EPROM. This was a 60 nsec part,
but it was not
reprogrammable.
The board could be addressed on 64K boundary in the 24-bit address space.
The board responded to the Phantom line. However the board did not have
circuitry for 16-bit data transfers and so was limited in use (and demand) for
16 bit CPU's appearing at the time.
The manual for this board can be obtained
here.
Static Memory Systems
S-100 Boards
64K RAM
This page was last modified
on
10/25/2013
