Anritsu MG369 C Series, Programming Manual

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1-5 IEEE-488 Interface Bus Description General GPIB Information
1-6 PN: 10370-10374 Rev. F MG369xC GPIB PM
General Interface Management Bus Description
The general interface management bus is a group of five signal lines used to manage the flow of information
across the GPIB. A description of the function of each of the individual control lines is provided below.
ATN (Attention)
The active controller uses the ATN line to define whether the information on the data bus is a command
or is data. When ATN is TRUE (low), the bus is in the command mode and the data lines carry bus
commands. When ATN is FALSE (high), the bus is in the data mode and the data lines carry
device-dependent instructions or data.
EOI (End or Identify)
The EOI line is used to indicate the last byte of a multibyte data transfer. The talker sets the EOI line
TRUE during the last data byte.
The active controller also uses the EOI line in conjunction with the ATN line to initiate a parallel poll
sequence.
IFC (Interface Clear)
Only the system controller uses this line. When IFC is TRUE (low), all devices on the bus are placed in a
known, quiescent state (unaddressed to talk, unaddressed to listen, and service request idle).
REN (Remote Enable)
Only the system controller uses this line. When REN is set TRUE (low), the bus is in the remote mode
and devices are addressed either to listen or to talk. When the bus is in remote and a device is addressed,
it receives instructions from the GPIB rather than from its front panel. When REN is set FALSE (high),
the bus and all devices return to local operation.
SRQ (Service Request)
The SRQ line is set TRUE (low) by any device requesting service by the active controller.
Device Interface Function Capability
An interface function is the GPIB system element which provides the basic operational facility through which a
device can receive, process, and send messages. Each specific interface function may only send or receive a
limited set of messages within particular classes of messages. As a result, a set of interface functions is
necessary to achieve complete communications among devices on the GPIB. ANSI/IEEE Std 488.1 defines each
of the interface functions along with its specific protocol.
ANSI/IEEE Std 488.2 specifies the minimum set of IEEE 488.1 interface capabilities that each GPIB device
must have. This minimum set of interface functions assures that the device is able to send and receive data,
request service, and respond to a device clear message.
Table 1-2 lists the interface function capability of the
series MG369xC signal generator.