Apple Elite Series Computer Drive User Manual


 
ELITE SERIES USER MANUAL THEORY OF OPERATION
DOS 3.3 re-enters at $Cn5C using a 6502 JMP.
When the PROM is finished, the second stage
expects it to transfer control back, via a JMP,
to $801.
DOS 3.2.1 does not expect the boot PROM to try
to decode the data read on the later calls (the
boot sector is a special encoding scheme which
differs from the rest of a 13 sector disk).
However, DOS 3.3 does require the boot PROM to
decode on these later sectors.
NOTE: The Rana boot code adheres to all the
above standard Apple DOS booting protocols, and
to several extensions to this protocol in order
to support existing software packages.
7.2.3.Hardware
The Elite Controller Card has full data buffer-
ing, using a bi-directional bus driver, which
pro vides more drive than other controllers yet
requires very little drive from the bus. Exten-
sive power switching reduces the power consump-
tion of the data buffer and other circuits.
7.2.4.EPROM Logic
The EPROM is split into two sections ($000—$6FF
and $ 700-$7FF). Both sections are mapped into
$C800-$CFFF; however only the $000-$6FF section,
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