RANA Systems Elite Controller, User Manual

Page: 173 / 328

ELITE SERIES USER MANUAL THEORY OF OPERATION
which maps into $C800-$CEFF, is intended to be
used at this location. The second section is
mapped into the slot-dependent location in the
Apple memory as illustrated in the table below.
Slot Memory Address for EPROM ($700-$ 7FF)
0 (not allowed)
1 $C100—$C1FF
2 $C200—$C2FF
3 $C300—$C3FF
4 $C400—$C4FF
5 $C500—$C5FF
6 $C600—$C6FF
7 $C700—$C7FF
Fig. 7-2: Slot Dependent PROM Address Ranges
This slot dependent portion of the EPROM is
always there. The mapped-in section, at $C800—
$CFFF, is only there after an access to the slot
dependent area. However, before accessing the
expansion area a command must be given to turn
off all the other ROMS that might be on the bus
(an access at $CFFF) which also turns off the
Rana EPROM. When the expansion RCA area is map-
ped Out from within the slot dependent ROM code,
the following instruction fetch made by the 6502
will cause the Elite Controller’s RON to be
mapped back in. This allows the slot dependent
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