The Hp Interface Bus; The H P Interface Bus; Hp-113 Lines And Operations - HP 1630A Operating And Programming Manual

Model 1630A/D/G
An HP-113 Overview
10 . The Status Bit Message - A byte that represents the operational conditions of a group of devices on the
bus. Each device responds on a particular bit of the byte thus identifying a device-dependent condition .
This bit is typically sent by devices in response to a parallel poll operation .
The Status Bit Message can also be used by a controllerto specifythe particular bit and logic level that a
device will respond with when a parallel poll operation is performed . Thus more than one device can
respond on the same bit.
11 . The Pass Control Message - This transfers the bus management responsibilities from the active
controller to another controller .
12 . The Abort Message - The system controller sends this message to unconditionally assume control of
the bus from the active controller. This message terminates all bus communications (but does not
implement a Clear Message) .
These messages represent the full implementation of all HP-113 system capabilities . Each device in a system
may be designed to use only the messages that are applicable to its purpose in the system . It is important for
you to be aware of the HP-113 functions implemented on each device in your HP-113 system to ensure the
operational compatibility of the system .
THE HP INTERFACE BUS
HP-113 Lines And Operations
The HP Interface Bus transfers data and commands
between the components of an instrumentation system
on 16 signal lines. The interface functions for each system
component are performed within the component so only
passive cabling is needed to connect the systems . The
cables connect all instruments, controllers, and other
components of the system in parallel to the signal lines.
The eight Data I/O lines (DI01 through D108) are reserved
for the transfer of data and other messages in a byte-
serial, bit-parallel manner . Data and message transfer is
asynchronous, coordinated bythe three handshake lines:
Data Valid (DAV), Not Ready For Data (NRFD), and Not
Data Accepted (NDAC) . The other five lines are for
management of bus activity . See the figure on the right.
Devices connected to the bus may be talkers, listeners, or
controllers. The controller dictates the roll of each of the
other devices by setting the ATN (attention) line true and
sending talk or listen addresses on the data lines.
Addresses are set into each device at the time of system
configuration either by switches built into the device or by
jumpers on a PC board . While the ATN line is true, all
devices must listen to the data lines. When theATN line is
false, only devices that have been addressed will actively
send or receive data . All others ignore the data lines.
9872-R-173-1
1 . . .8
DA V
NRFD
NDAC
IFC
ATN
SRQ
REN
EOI
Several listeners can be active simultaneously but only
one talker can be active at a time . Whenevera talk address
is put on the data lines (while ATN is true), all othertalkers
will be automatically unaddressed.
HP-113 Signal Lines
B- 3
e .g .
multimeter)
UNIONISM
MARMEM
111111 General
Interface
DEVICE C
00
1U//"
Management
MIMS
Only able to
MOM
010141101011111
listen
(e.g ., signal
generator)
mmomomem
1111111
V
DEVICE D
able
Only
to moss
talk
MEMO
11001111111
le .g ., counter)
011011021011011
MOINEEM
10101210101011010
DIO
DEVICE A
Data Bus
(8 Lines)
Able to talk,
listen, and
control
(e .g .
calculator)
Data Byte
DEVICE B
Transfer
8~l~
Control
Able to talk
and listen