The Thinker Toys 24K Memory Master was
their second entry into the field of bank select S-100 memory products. Using
the popular 5257 4K x 1 static RAM memory chip with an access time which allowed
them to guarantee operation with 4MHz Z-80 systems and 5MHz 8085 systems, the
24K Memory Master was compatible with most popular S-100 bank select software.
This versatile board could be switched to become selected or deselected in
response to any bit of any I/O port; to come up active or inactive on power-up;
and to honor or ignore the PHANTOM bus signal. Once selected, the unit could be
configured as three independently addressable and write protectable 8K blocks,
with addressing allowed at the beginning of any 8K boundary.
The manual for this board can be
obtained here.
