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CHAPTER 4: IEEE Operating Modes
You can also detect these conditions with the ARM or ON DOMACRO commands and handle them in an
exception as described in
Chapter 5
. The various arm conditions and their meanings are as follows:
SRQ
The internal Service Request state is set. See the SPOLL command in
Chapter 5
.
PERIPHERAL
The 488 Controller is in the Peripheral (*CA) operating mode.
CONTROLLER
The 488 Controller is the Active Controller (CA).
TRIGGER
The 488 Controller, as a Peripheral, has received a Trigger bus command.
CLEAR
The 488 Controller, as a Peripheral, has received a Clear bus command.
TALK
The 488 Controller is in the Talk state and can OUTPUT to the bus.
LISTEN
The 488 Controller is in the Listen state and can ENTER from the bus.
IDLE
The 488 Controller is in neither the Talk nor Listen state.
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 488 Controller.
4.5 Not System Controller Mode
If the 488 Controller 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 488 Controller 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.
