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3.8.2.4 Outputting Data with Listen Handshake Enabled
When Listen Handshaking is enabled, the 4863 tests the Status A input and
only outputs data if the Status input is in its true state. Else the 4863 will
report an Execution Error and discard the data. The recommended proce-
dure is for the user to test the Status A input before outputting data if Listen
handshaking is enabled. If multiple sets of data are being outputted to a
device with Listen Handshaking enabled, the 4863 will wait 100 msec for
the external device to complete its handshaking before starting the next data
set. If the external device does not complete its handshake within the 100
msec period, the 4863 will abort the command and report an Execution
Error.
3.8.2.5 Configuring Individual Input Bytes
It is not necessary to configure individual bytes with the Configuration
commands. Individual input bytes are configured and read with the SCPI
SENSE subsystem. The :PORTn? command automatically sets the byte for
inputting data when it is read. The :POLarity command configures the input
polarity on a bit-by-bit basis. In the example cable, the bits are all high true.
The example sense commands are:
e.g. SENSe:DATA:PORT1:POLarity #hFF
'sets all bits high true
SENSe:DATA:PORT1?
'reads byte 1
3.8.2.6 Configuring Individual Output Bytes
It is not necessary to configure individual bytes with the Configuration
commands. Individual output bytes are configured and outputted with the
SCPI SOURCE subsystem. The SOURce:DATA:PORTn command sets
the byte as an output when data is written to the byte. The :POLarity
command configures the output polarity on a bit-by-bit basis. For the
sample cable, the output bits are all low true. Polarity is programmed first
so the example source commands are:
e.g. SOURce:DATA:PORT6:POLarity #h00
'sets all bits low true
SOURce:DATA:PORT6 0
'selects byte 6 for output,
and sets bits to 0