Measurement Computing Micro 488/EX rev.2.1 - Manual (Page 81)

Section 5 Command Descriptions
5.11
ABORT
As the System Controller (SC), whether the Micro488/EX is the Active
Controller or not, the ABORT command causes the Interface Clear (IFC) bus
management line to be asserted for at least 500 microseconds. By asserting IFC, the
Micro488/EX regains control of the bus even if one of the devices has locked it up
during a data transfer. Asserting IFC also makes the Micro488/EX the Active
Controller. If a Non-System Controller was the Active Controller, it will be forced to
relinquish control to the Micro488/EX. ABORT forces all IEEE bus device interfaces
into a quiescent idle state.
If the Micro488/EX is a Non System Controller in the Active Controller state
(*SC•CA), it asserts attention (ATN), which halts any bus transactions, and sends its
talk address to "untalk" any other talkers on the bus. It does not (and cannot) assert
IFC if in the *SC state.
SYNTAX ABORT
or
AB
RESPONSE None
MODE SC or *SC•CA
BUS STATES IFC, *IFC (SC)
ATN•MTA (*SC•CA)
EXAMPLES PRINT#1,"ABORT"
PRINT#1,"AB" Using abbreviated form