California Computer Systems -
2065A 64K Dynamic RAM Board
CCS made two 64K Dynamic RAM boards.
This was their first one.
CCS's 2065A 64K Dynamic Ram board
provided S-100 systems with 64K of reliable, high-speed dynamic RAM. Compatible
with most of the major S-100 systems on the market at the time, including those
with front panels, it supported DMA operations and required no Wait states with
up to 4MHz microprocessors. The 2065 was designed for memory
expansion; it allowed you to expand your memory up to 512K.
The manual for this board can be
Through the bank select
system, you could hardware-assign your board to any level or combination of
levels of 64K and then software-select the bank you wish to work with. When the
board's bank was selected, the Bank LED lit. The 2065's bank select system was
compatible with the bank select systems used by Cromemco, North Star, and
others. In addition, the 2065 give you flexible
memory. Any 16K memory block could be completely disabled or can be made
independent of the bank select system, allowing it to be enabled any time it is
addressed, regardless of which bank was selected.
All 64K could also be enabled
every time you turn on or reset your system, without the board's bank being
software-selected first. When an enabled 16K block was addressed, the Board LED
is lit. The 2065 give fairly reliable memory.
Its dynamic memory refresh circuitry provided processor-transparent refreshes
during normal operations with a Z-80 or 8080 CPU. It also provided for memory
refresh during DMA and extended Wait states when normal refresh generation was
Other California Computer
Systems S-100 Boards
2065 64K RAM
2066 64K RAM
Serial & Parallel
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