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3.8.2.2 Configuring the Listen String (Digital Outputs)
The SCPI CONFIGURE and FORMAT subsystems are used to configure
the digital interface before an output string can be used to output data to an
external device. The FORMat:LISTen command provides the user with
four formats for outputting data to the 4863. ASCii lets the user send the
byte output value as decimal numbers from 0 to 255. The numbers are
separated by commas. HEXL is similar but it uses two HEX characters from
00 to FF also separated by commas. HEX is the same as HEXL but without
the commas between bytes. 4833 is like HEX but it uses the 4833 rule of
only accepting ASCII characters with hex values of 30 thorough 3F. These
are the numbers 0-9 and :;<=> and ?. The following example shows the four
formats being used to output 24 bits of data or three bytes:
e.g. Outputting (0000 0001 0001 0111 1111 1110) with four formats:
Format
Sequence
ASCii
1,23, 254
HEXL
01,17,FE
HEX
0117FE
4833
0117?>
The output string can be sent using the SOURce:DATA command using a
single primary address. The output string can also be sent as a transparent
string using a second primary address or the upper secondary address.
For most applications, the user will send one set of data in a single command
that is terminated with a linefeed or by asserting EOI. However, in some
applications, the user might want to send multiple values to the output ports.
The 4863 will accept multiple sets of output values in the same command
line and generate data strobes for each set as long as they are separated by
commas. An output strobe pulse will be generated for each comma between
the sets of data. List formats like ASCii or HEXL that use commas to
separate bytes, require a double comma to generate an output strobe. If the
comma is missing, the 4863 will not generate a data strobe. The 4863 will
repeat outputting data to the output ports listed in the last CONFigure:OUTput
command until the command terminator is reached. Some examples are:
Format
Sequence
ASCii
1,23, 254,,129, 255,1 <nl>
HEX
1234,ABCD,1AC2 <nl>
