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NSTALLATION
AND
OPERATION
Table
2-10.
IEEE-488 Address
Mode
Message
Descriptions
MESSAGE
DESCRIPTION
pon
Power-On
Talker
Operation
When powered
up,
the
Generator generates
a
Power-
On message
(pon) and
clears
its
output buffer. The
Generator
is
not
addressed to
talk
when powered
up.
Li
stener
Operation
The Generator
is
not
addressed
to listen when the power
is
turned
on.
Service
Request
Operation
HTA
My Talk Address
The state
of
the
Service Request
(SRQ)
signal
on
pon
is
determined
by the SRQ
mask. The SRQ mask
is
the same as
when the power
was removed-
Therefore,
if
the SRQ mask
enables
the
power
on,
output valid,
or
ready SRQs, the
SRQ signal will be true
during
pon.
Talker
Operation
The
Generator
is
addressed to
talk upon receipt
of
the
MTA message. The front panel ADDR indicator
is
lit
while
the
Generator
is
addressed
to talk.
Listener
Operati on
The Generator unlistens
when
the
MTA message
is
received.
MLA
My
Listen Address
Talker
Operation
The Generator untalks when the MLA
message
is
received.
Li
stener
Operation
The Generator
is
addressed to
listen when the MLA
message
is
received. The front panel ADDR indicator
of
the Generator
is
lit
while
the
Generator
is
addressed
to listen.
Data
Talker
Ope ration
The Generator sends data to the IEEE-488 bus only when
requested
by
a
programming data message. Message formats
are described
in
the
Command Description paragraphs.
An
End of
Record
(EOR)
character
is
sent with EOI
asserted
following
all outputs.
The EOR character
is
either
a
carriage
return
or
a
Line
feed, depending on the setting
of
the terminator mode. The parity bit
is
always
zero.
Multiple
output requests
are buffered until
the buffer
is
full.
Processing
of
programming
data messages
is
stopped
until the
buffer
is
no longer
full. The
buffer
can be
cleared with the Clear Buffer command
("CB"). The
buffer
is
also cleared on power up (pon), with
a
Clear
Command ("CL"),
or
with
a
Device Clear interface message
(OCL
or
SDC).
Li
stener
Operation
Command syntax, error processing, and
input
buffer
overflow
are
described
in
the paragraphs
on
Ccmimand
Processing. Refer
to
Table 2-8
for
a
list of
IEEE-488
commands
that
are recognized
by the Generator.
IFC
Interface Clear
Talker
Operation
The
Generator untalks and unlistens when
the IFC
message
is
received.
2-44
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