HP 5340A Operating And Service Manual page 21

Model 5340A
Installation and Remote Programming
d. ATTENTION (ATN)
ATN is used by a controller to address a 5340A. The 5340A monitors ATN at all times.
When ATN is low, all 5340A's connected to the bus interpret the information on the
data lines' as a n address. They will handshake on the appropriate lines and will not
drive the data lines. The 5340A requires the controller to hold ATN low for 1 psec
before it sets the handshake line DATA VALID low.
When ATN is high, a 5340A that has been addressed to TALK will drive the data lines.
Those that have been addressed to LISTEN will interpret the information on the data
lines as program data. Those that have not been addressed will not drive the data
lines.
e. DATA LINES (EIGHT-BITS DIO1, D102
these lines when it has been addressed to TALK. The 5340A receives information on
the data lines when addressed to LISTEN or when ATN is low. D108 is permanently
terminated in the 5340A.
When a DIO line is high, the data bit is a logic zero (0).
When a DIO line is low, the data bit is a logic one (1).
f. READY FOR DATA (RFD)
RFD is the handshake line that indicates LISTENERS are ready to accept information
on the data lines. Its relationship to the other handshake lines and ATN is shown in
Figure 2-1 and Table 2-1.
RFD is driven by LISTENERS: all 5340A's when ATN is low and those instruments
addressed to listen when ATN is high. It is sensed by TALKERS: the controller when
ATN is low, and the instrument addressed to talk when ATN is high.
When RFD is high, all listeners are unconditionally ready for data. The TALKER may,
at its own time, put a byte of information on the data lines and set DAV low. When
RFD is low, one or more listeners are not ready for data.
When the controller sets ATN low, all 5340A's will set RFD to its valid state within
200 nsec. When the controller sets ATN high, all 5340As that have not been addressed
to listen will not drive RFD, those addressed to listen will set RFD
nsec.
200
The listener must not set RFD low until it senses DAV is low. It may do so before or at
the same time that it sets DAC high. It must not return RFD high until it senses DAV is
high and may do so after, or at the same time that it sets DAC low.
g. DATA ACCEPTED (DAC)
DAC is the handshake line that indicates the acceptance of information on. the data
lines. Its relationship to the other handshake lines and ATN is shown in Figure 2-1
and Table 2-1.
DAC is driven by LISTENERS: all 5340As when ATN is low and those instruments
addressed to listen when ATN is high. It is sensed by TALKERS: the controller when
ATN is low and the instrument addressed to talk when ATN is high.
When DAC is hig ,/all LISTENERS have anconditionally accepted the byte of infor-
DAV high, remove that byte of information and continue. When DAC is low, one or
more LISTENERS have not accepted the information on the data lines.
2-4
...
lines and no longer need it. The TALKER may, at its own time set
its valid state within
to