Measurement Computing Analyzer488 - Manual (Page 162)

Section 4 Serial Controller
4.68
EOI {'data'|char[,char…]}
Send character strings, data, or characters with numeric
ASCII values, char. ATN is unasserted. EOI is
asserted on the last character.
CMD {'data'|char[,char…]}
Send character strings, data, or characters with numeric
ASCII values, char. ATN is asserted.
ENTER Request data from a device terminating on LF. ATN is
unasserted.
The DATA, EOI and, CMD sub-commands send data bytes or
characters over the bus. The characters to be sent are specified either
as a quoted string ('data') or as individual ASCII values
(char[,char…]). For example, DATA'R0X' sends the characters
R
, 0, and X to the active listeners, and DATA 13,&H0A sends
carriage-return and line-feed. Multiple ASCII char bytes may be
specified by separating them with commas.
The EOI sub-command is identical to the DATA sub-command
except that the End Or Identify (EOI) signal is asserted on the
transfer of the last character.
The CMD sub-command sends the data bytes with Attention
(ATN) is asserted. This tells the bus devices that the characters are
to be interpreted as IEEE 488 bus commands, rather than as data.
EOI is not asserted during CMD transfers. For example CMD &H3F
is the same as Unlisten (UNL). Note that it is not possible to assert
EOI during the transfer of a command byte because EOI and ATN
together specify an IEEE parallel poll command.
The ENTER sub-command inputs data from the active talker,
which has been set to Talk from either a TALK addr sub-
command, or a previous ENTER command. Addresses are not
allowed to be specified as options to this sub-command. The ENTER
sub-command will terminate upon detection of a Line Feed (LF)
character.
Note that the maximum length of the SEND command,
including any sub-commands, is 127 characters. If large amounts of