Hp-Ib Pin-Out Description - HP 8340A Operating Manual

Operating Information

HP-IB Pin-Out Description

Figure 3-25 shows a detailed view of the HP-IB connector, with a pin-out description. Notice
that HP-IB has 16 dynamic, TTL-level signal lines which can be categorized into three
groups: data lines, handshake lines, and system control lines. The signal level on these
lines is either TTL low (a "True" condition), TTL high (a "False" condition), or floating
(electrically disconnected).
SHOULD BE GROUNDED
NEAR TERMINATION
OF OTHER WIRE
OF TWISTED PATH
Data lines, DI01-DI08.
on the eight HP-IB data lines as a series of eight-bit bytes, with DIOl being the least
significant bit (LSB) and DI08 being the most significant bit (MSB). The meaning of each
byte is arbitrary, being different for each type of instrument. The rate of data transfer is
controlled by the handshake sequence.
Handshake lines, DAV, NRFD, NDAC.
process.
DAV, Data Valid, line is high (False - data not valid) or low (True - data valid) to
indicate the validity of the signals on the DIO lines.
NRFD, Not Ready for Data, line indicates whether the instruments receiving data are
prepared to accept that data; NRFD is either low (True - the instrumen�s are not ready
for data) or high (False - the instruments are ready for data).
NDAC, Not Data Accepted, line indicates whether the data-receiving instruments have
accepted the transmitted data. The NDAC is either high (False - the data has been
accepted) or low (True - the data has not been accepted).
Figure 3-26 illustrates a representative handshake timing sequence.
3-78
SIGNAL GROUND
P/0 TWISTED PAIR WITH 11
P/0 TWISTED PAIR WITH 10
P/O TWISTED PAIR WITH 9
P/0 TWISTED PAIR WITH 8
P/O TWISTED PAIR WITH 7
P/0 TWISTED PAIR WITH 6
REN
D108
D107
D106
0105
NOTE
The HP·IB logic levels are
TTL compatible, le., true
state 0 V de to 0.4 V de,
False State+ 2.5 V de to
+5Vdc.
Figure 3-25. HP-IB Pin-Out
These are the eight Data Input/Output lines. Data is transceived
These three lines control the data transfer
Scans by HB9HCA and HB9FSX
CONNECT TO
,.___ __ __. . EAR TH
·SHIELD
GROUND
ATN
SRO
IFC
NDAC
NRFD
DAV
EOI
0104
D103
D102
D101
Model 8340A