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different bit on each board to be bank switched. If you
want to combine two 32K HRAM boards into a single
larger bank, program both boards with the same bit. A
64K cannot be divided into two different 32K banks.
It is possible to use earlier North Star RAM-32 or RAM-
16 boards in conjunction with HRAM boards to create a
bank switching system.
3.2.3
Software Instructions
The following instructions are an example of how to
turn on or off memory bank 3. Memory bank 3 is composed
of all those RAM boards that are configured to use I/O
bit 3 for bank switching.
MVI A,08H ; Turn on bank 3
OUT 0C0H
MVI A,09H ; Turn off bank 3
OUT 0C0H
Note that bit 0 is used to specify turning the bank on
or
off.
instructions accordingly. For example, to turn bank 5
on and off, the operands should be 20H and 21H instead
of 08H and 09H.
HRAM
JP1 Set For Bank 3
must
position
For
different
Figure 3-6
the
jumper-plug
banks,
change
USER/TECHNICAL MANUAL
to
designate
the
program
a
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