VXI VT1422A, VT1529A/B user manual STATus

VT1422A Command Reference 379Chapter 7
STATus
STATus
The STATus subsystem communicates with the SCPI defined Operation and
Questionable Data status register sets. Each is comprised of a Condition register, a
set of Positive and Negative Transition Filter registers, an Event register, and an
Enable register. Condition registers allow the current real-time states of their status
signal inputs (signal states are not latched) to be viewed. The Positive and Negative
Transition Filter registers allow the polarity of change from the Condition registers
that will set Event register bits to be controlled. Event registers contain latched
representations of signal transition events from their Condition register. Querying an
Event register reads and then clears its contents, making it ready to record further
event transitions from its Condition register. Enable registers are used to select which
signals from an Event register will be logically OR’ed together to form a summary
bit in the Status Byte Summary register. Setting a bit to 1 in an Enable register enables
the corresponding bit from its Event register.
Note For a complete discussion, See “Using the Status System” on page 142.
Figure 7-5. General Status Register Organization
Condition
Register
Bit0
Bit1
Bit15
Bit14
Event
Register Enable Register
Logical
OR
SummaryBit to
StatusByte
Positive/Negative
TransitionFilter
latch
latch
latch
latch
=1
=1
=1
=1
=1
=1
=1
=1