9132A Service
Section
2
Theory
of
Operation
GENERAL THEORY OF OPERATION
2-1.
The 9132A (referred to hereafter
as the
Pod) interfaces the 9100-Series
Mainframe
to
a unit under test (UUT). The Pod receives commands from
the Mainframe and processes the commands
so
they can
be
executed on the
UUT. The 9132
is
a memory emulation Pod, that is,
it
takes control of the
UUT’s memory and uses the processor on the UUT to execute the Pod’s
commands. To do this, the Pod plugs into or attaches to the UUT Boot ROM
sockets, effectively replacing
the
memory in them. The other feature required
for controlling the UUT
is
the
ability to drive or overdrive the UUT
reset
line.
To take command or control of
the
UUT, the Pod resets the UUT and the
code that originally came from UUT boot
ROMs
is
replaced
by
the code from
the Pod. This code then executes the user's instructions.
The Pod also monitors some microprocessor lines directly. Eight lines
for
timing control (either status or control
lines)
monitor
the state
of
the UUT
microprocessor.
Basically, these lines form a “sync” signal used by the
Mainframe or user at a required access
time.
The other
use
of the
sync
signal
is
for returning data.
Eight data lines are also monitored and
functionally return data from the UUT’s microprocessor to the Pod
by
means
of byte writes
to an
address called a “transfer address”.
When
this
operation occurs, the
sync
pulse (generated from
the
Pod) loads the data at
the microprocessor data bus into a latch, which
can
be read
by
the Pod.
THEORY OF OPERATION
2-2.
A block diagram of each major Pod
section
is presented in Figure
2-1.
Each
major section
is
described in the following paragraphs. Component
designators such
as
“Uxx”
and
signal names refer to schematic diagrams
in
Section
5.
NOTE
Signal names appear as
in the
schematic diagrams.
Signal names that end
in “-” (e.g., BERR-)
indicate an
active state
at
low voltage.
Main
Board Kernel
2-3.
The Main Board kernel circuitry
is
shown
on
page
1
of the Main Board
schematic (Figure
5-1).
Summary of Contents for 9132A
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