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8-241. The keyboard has 34 momentary-contact push-button switches. The keyboard status is continuously
monitored through a 9 X 4 line matrix with nine strobe lines (XO to X8) from the demultiplexer in the Executive
Block, and four scan lines (YO to Y3) that input directly to the Executive MCU.
8-242. A2 Front Panel Board Circuit Description
8-243. FRONT PANEL MONITORING. The Executive MCU outputs a sequence of nine 4-bit binary codes
to the demultiplexer. As the Executive MCU outputs each Cbit code, it forces one of nine strobe lines (XO to
X8)
to go LOW. While the strobe line is forced LOW, the Executive MCU then senses each of the four scan
lines (YO to Y3) which are normally HIGH. The MCU then outputs the next Cbit code in the binary sequence
until all strobe lines have been accessed, repeating the process continuously. If a key is pressed, a particular
strobe line is shorted to one of the scan lines forcing the scan line to go LOW. The MCU determines which key
has been pressed by the combination of strobe and scan lines going LOW at the same time.
8-244. The front panel annunciators, including the display digits and key lamps, are controlled by Executive
MCU (except both TRIGGER LEVEL A and B, ARM, GATE, and STANDBY LEDs). The annunicators are
driven by two drivers (U1 and U2), which receive data from the Executive MCU over the Executive Data Bus.
The eight most significant digits in the mantissa are driven by U1, while. the remaining digits, annunicators, and
key lamps are driven by U2. Data transfer is controlled with the two strobe lines (STR1 and STR2) and MODE
selection line.
8-245. DATA
TRANSFER.
To initiate a measurement cycle, the Executive MCU first pulls STRl LOW with
the MODE line HIGH, then sends a Cbit control word to driver U1 over the Executive Data Bus. Next, the
MODE line is pulled LOW. Then on successive HIGH-to-LOW transitions of the STRl line, eight bytes of data
are automatically sequenced over the Executive Data Bus to eight memory locations in the driver's 8 x
8
internal
static memory. Further transitions of the STRl line are ignored and the driver returns to normal display opera-
tion until a new control word is transferred. Data is then transferred to driver U2 in the same manner with the
STR2 line controlling the data transfer. After a data transfer, the drivers clear the display, and light the ap-
propriate annunciators and key lamps. The Executive MCU then directs the Measurement MCU to start and
compute the corresponding measurement.
8-246. MATE (CIIL) BLOCK (OPTION 700)
8-247. The Option 700 MATE Block allows the HP 5334B to respond to an additional control language called
Control Interface Intermediate Language (CIIL). The instrument will still respond to its native (HP-IB) program-
ming code, but this would only normally be used for troubleshooting and HP-IB operational verification.
8-248. The MATE Block acts as a link between the HP-IB and the Executive microcomputers (MCUs). The
MATE Block operates in one of two modes (CIIL or NATive) determined by the setting of a shorting jumper,
5701, in the MATE Block or software commands sent to the MATE Block.
8-249. In the native (NAT) mode, the MATE Block is transparent and the communication between the HP-IB
and Executive MCUs is as if the HP 5334B does not include the MATE Block. In the CIIL mode, the MATE
Block acts
as
a translator. CIIL commands sent to the instrument are translated by the MATE Block into com-
mands understood by Executive MCU U19.
8-250. The Option 700 MATE Block contains the following major circuits:
Clock and Logic Driver
Address Latch
Data Buffer
Read~Write Decode
Executive and HP-IB InputDutput
HP 5334B
-
Service
Manual
8-32
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Table of Contents
Troubleshooting
