HP 8340b User Manual

Front Panel
Theory
of
Operation
FRONT
PANEL
MICROPROCESSOR
The front
panel
assembly contains
a
microprocessor
that
is
used
to refresh
the
displays.
The
main
instrument
microprocessor sends
data
to the
front
panel
processor
via
the
instrument
data
bus and
instrument
address
bus.
The
front
panel
processor
stores
the
data
in
an
internal
RAM
(random
access
memory)
buffer.
The
front
panel
processor
has
2K
of
internal
ROM
(read
only
memory)
that
contains
a
program
to
generate
the
necessary
control
signals to
display
and refresh
data.
DISPLAYS
The
synthesizer has
two
types
of displays:
•
Entry display
Includes
twenty-eight
5
X 7
dot
matrix
characters,
and
can
display
both
alpha and
numeric
data.
•
Frequency
and
power
displays
Seven-segment
displays
that
usually
display
only
numeric
data.
The front
panel
processor
determines
the
segments
and/or
dots to
be
illuminated
and
outputs
the
appropriate
digital signals
to
the
appropriate
circuitry,
continually refreshing
the
displays.
LED ANNUNCIATORS
The
main instrument
microprocessor
controls
the
LED
annunciators
via
the
instrument
data
bus
and
instrument
address
bus.
KEYBOARDS
The
two
keyboard
assemblies
(A5
and
A7),
and
the
RPG
(rotary
pulse
generator) communicate
with
the
main
instrument microprocessor
via
the
A6
keyboard interface
assembly.
Pressing
a
key
gener¬
ates
an
active
low column
signal and
an
active
low
row
signal
that
are
encoded
by
the
keyboard
interface
assembly.
A
service
request
is
generated
to the
main instrument
microprocessor,
which
reads
the
encoded
signal
via
the
instrument
data
bus.
G
-2
Front Panel
Theory
of
Operation
HP 8340B/41B

HP 8340b Specifications

General

Brand	HP
Model	8340b
Category	Inverter
Language	English