GPIB IEEE488 MANUAL COMMAND FORMAT
3.0 MODES OF OPERATION
In the interests of conciseness for the more experienced
programmer and user, this section has been written as a reference
and initially may be difficult to understand. If this is the
case, refer to Appendix F where a step by step real programming
example read together with this
section provides an easier
introduction.
All modes of operation are determined by an
ASCII
STRING
in a command (COMMANDS or CMD$) referenced within a CALL
statement. The CALL statement format is:
XXX CALL IE488 ( COMMAND$, varf$I(%), FLAG%, BASADR% 1
where:
COWHANDS
- is the COMMAND
including
device addresses or
secondary commands and
[ image terminators 1. This
is always a STRINGandisdecodedbythe CommandLine
Interpreter in the IE-488 firmware (ROM). The
COMMAND is separated from the operands (devices etc.)
by one or more SPACES,
any other delimiters will
cause a SYNTAX error in command line. The separator
for devices is always the comma "," andsecondary
address is always a period ".". The IMAGE string is
identified by brackets "[I". The Command
Line
Interpreter is relatively tolerant of syntax error
identification and will send back the appropriate
error code to isolate the error. The format is:-
CMD$ =
"COMMAND devl, dev2, . . . ..devn [image]"
The
[image]
specifier allows the user to specify the
variable field operations for the beginning and end
of the data transfer variable. The variable may be a
variable name,
array identifier, numeric data value
or a string. The user must match the image to the
data type or an error will be generated in the
data
transfer. No check is made in the match of the image
to the variable type,
this is the responsibility of
the user.
The [image] codings are explained in
section 3.1 (IMAGE SPECIFIERS).
varC$l(%) - isthe data variable OUTPUT/INPUT to be transferred
from/to. Datais transferred
as specified by the
image terminator/specifier. If the image specifier
is not used the data is treated as an integer. The
data may be of String or Integer type.
FLAG% ---
is the transfer status of the CALL statement. If an
error occurs FLAG%
will
contain a
HEX
number
representing the error condition.
A set of error and
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