DS75162A Datasheet, PDF (5/10 Pages) National Semiconductor (TI) – IEEE-488 GPIB Transceivers

Functional Description
DS75160A
This device is an 8-channel bi-directional transceiver with
one common direction control input denoted TE When
used to implement the IEEE-488 bus this device is connect-
ed to the eight data bus lines designated DIO₁ – DIO₈ The
port connections to the bus lines have internal terminators
in accordance with the IEEE-488 Standard that are deacti-
vated when the device is powered down This feature guar-
antees no bus loading when V_CC e 0V The bus port out-
puts also have a control mode that either enables or dis-
ables the active upper stage of the totem-pole configura-
tion When this control input denoted PE is in the high
state the bus outputs operate in the high-speed totem-pole
mode When PE is in the low state the bus outputs operate
as open collector outputs which are necessary for parallel
polling
DS75161A
This device is also an 8-channel bi-directional transceiver
which is specifically configured to implement the eight man-
agement signal lines of the IEEE-488 bus This device
paired with the DS75160A forms the complete 16-line inter-
face between the IEEE-488 bus and a single controller in-
strumentation system In compliance with the system orga-
nization of the management signal lines the SRQ NDAC
and NRFD bus port outputs are open collector In contrast
to the DS75160A these open collector outputs are a fixed
configuration The direction control is divided into three
groups The DAV NDAC and NRFD transceiver directions
are controlled by the TE input The ATN SRQ REN and
IFC transceiver directions are controlled by the DC input
The EOI transceiver direction is a function of both the TE
and DC inputs as well as the logic level present on the ATN
channel The port connections to the bus lines have internal
terminators identical to the DS75160A
DS75162A
This device is identical to the DS75161A except that an
additional direction control input is provided denoted SC
The SC input controls the direction of the REN and IFC
transceivers that are normally controlled by the DC input on
the DS75161A This additional control function is instrumen-
tal in implementing multiple controller systems
Table of Signal Line Abbreviations
Signal Line
Classi-
fication
Mne-
monic
Definition
Device
DC Direction Control DS75161A
DS75162A
Control
Signals
PE Pull-Up Enable
TE Talk Enable
DS75160A
All
SC System Controller DS75162A
Data
I O Ports
B1–B8 Bus Side of Device
D1–D8 Terminal Side
DS75160A
of Device
ATN Attention
DAV Data Valid
EOI End or Identify
Management IFC Interface Clear
DS75161A
Signals
NDAC Not Data Accepted ^DS75162A
NRFD Not Ready for Data
REN Remote Enable
SRQ Service Request
Logic Diagrams
DS75160A
TL F 5804 – 4
5
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