Digital Research Computers -- 16K EPROM Board
This was a the first ROM board DRC made.
The board was an early board so it did not met the IEEE-696 specifications.
For example it had no 24 bit addressing. It utilized 16 450 nsec. 2708
EPROMS. The board had 0-4 wait state insertion capability and unused EPROM
sockets did not use up the 64K RAM address apace. There was an interesting
utilization of diodes to board deselect a particular EPROMs adderss space
within the CPU's 64K address space. It did support the S-100 bus Phantom
line for input but unfortunately not output (to inactivate othere
overlapping RAM on the bus).
The manual for this board can be obtained
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