Measurement Computing Micro 488/EX rev.2.1 - Manual (Page 41)

Section 3 IEEE Operating Modes
3.7
CHANGE An Address Change has occurred, i.e. a change between
Peripheral and Controller, or among Talk, Listen, and Idle
has occurred.
ERROR An error, either command or bus, has been detected by the
Micro488/EX.
STARTUP The non-volatile Macro capability provides the stand-alone
controller feature by allowing the Micro488/EX to execute a
Macro at STARTUP.
3.5 Not System Controller Mode
If the Micro488/EX is configured as not the System Controller then, at power on,
it will be a bus Peripheral. It might use a program like the one described previously to
communicate with the Active Controller. The bus commands available to the
Micro488/EX when it is not the System Controller and not the Active Controller
(*SC•*CA) are:
ENTER Receive data from a bus device as directed by the Active
Controller.
OUTPUT Send data to bus devices as directed by the Active
Controller.
REQUEST Set own Serial Poll request (including Service Request)
status.
SPOLL Get own Serial Poll request status.
3.6 Active Controller, Not System Controller Mode
If the Active Controller Passes Control to the Micro488/EX then it will become
the new Active Controller. This can be detected by the STATUS command or as an
ARM
ed event. As an Active Controller, but not the System Controller, the following
bus commands are available:
*ABORT Assert Attention and send My Talk Address to stop any bus
transfers.