Black Box 488 Controller, Руководство пользователя

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488 CONTROLLER
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If the 488 Controller is a Non-System-Controller in the Active Controller state (*SCCA), 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 *SCCA
BUS STATES IFC, *IFC (SC)
ATNMTA (*SCCA)
EXAMPLES PRINT#1,"ABORT"
PRINT#1,"AB"
Using abbreviated form
ARM Command
The ARM command allows the 488 Controller to automatically send event messages to the serial host when
one or more of the specified events occur. The event messages that are returned are the same non-
abbreviated strings as those used to program the events.
There are two types of events: level sensitive and edge sensitive. Level-sensitive events, such as SRQ, will be
reported every time they are ARMed while the event condition persists. Usually, some action must be taken
(for example, SPOLL) to clear the condition before re-issuing the ARM. Edge-sensitive events, such as
TRIGGER, are cleared when reported.
Regardless of the event sensitivity, the ARM command must be resent after the event message is reported to
reactivate the ARMed condition. The optional events include:
SRQ The event message SRQ is returned to the serial host when the state of the Service
Request Bus Line is detected in the asserted state. This event is level sensitive. If the
condition exists at the time the ARM SRQ command is issued, the 488 Controller will
return the event message immediately. If the ARM command is issued without any
specified events, the SRQ event is assumed. This provides upward compatibility with
the 488 Controller in previous 488 Controller systems.
PERIPHERAL The event message PERIPHERAL is returned to the serial host when the 488
Controller is forced from the Controller Active State (*SC-CA) to the Peripheral State
(*SC-*CA) when it receives IFC from the System Controller. This helps detect when
IFC is received in the *SC-CA state. This event is edge-sensitive.
CONTROLLER The event message CONTROLLER is returned to the serial host when the 488
Controller receives control of the bus and transitions from the Peripheral State
(*SC-*CA) to the Controller Active State (*SC-CA) . This occurs when the Take Control
interface message is received by the 488 Controller. This event is edge-sensitive.
TRIGGER The event message TRIGGER is returned to the serial host when the 488 Controller, as
a Peripheral (*CA), receives a Group Execute Trigger (GET) command from the
Active Controller. This event is edge-sensitive. When the event message is sent, the
internal status, as read by the STATUS 1 command, is cleared.