HP 8340B Manual page 245

A60 PROCESSOR ASSEMBLY
The A60 processor assembly performs
all instrument data processing. This assembly consist
of:
•
A
microprocessor
•
Memory
•
An
HP-IB
interface
•
The
necessary
circuTTry for:
clock generation
address and memory decoding
buffering
Interrupt handling
The microprocessor interfaces directly with memory, which consists
of:
•
64K
words of Ultra Violet Erasable Programmable Read Only
Memory (UVEPROM)
The
instrument software program
(firmware) is stored in
this section of memory, with the
default
calibration
data.
•
2K words of
Electrically
Erasable Programmable Read
Only Memory (EEPROM)
Protected calibration data is stored here,
•
8K words of
Random Access Memory (RAM)
Working calibration data and SAVE/RECALL register values are stored here. Battery backup
provides power to RAM when AC power
is disconnected.
If
the backup power
fails,
working
calibration data and
SAVE/RECALL
information
is
lost.
When AC power
is restored, the
EEPROM
calibration data
is loaded in
RAM,
and the front panel displays CALIBRATION
RESTORED.
NOTE:
1
word
=
2
bytes; 1
byte
=
8 bits.
The microprocessor is
controlled by the firmware stored
in
memory. With
this program, the
micro¬
processor can transfer
data (I/O addressing) and
internally process data
it
has accessed.
All
data
transfers go through the microprocessor.
The A60 processor assembly communicates
with the rest of
the instrument by
means
of the internal
address
and
data busses. External communication
is
through the HP-IB connection on the
rear panel.
The HP-IB interface
circuitry
provides the
link
between the
internal instrument bus
and the external
HP-IB Interface.
HP 8340B/41B
Change
7
Controller Section
Theory
of Operation F-5/F-6