Setting And Querying The Status Register 2-1 - Agilent Technologies ESA-E Series Programmer's Manual

Status Registers
Use Status Registers to Determine the State of Analyzer Events and Conditions
Once you have enabled a bit using the event enable register, th e
analyzer will monitor that particular bit . If the bit becomes true in
the event register it will stay set until the event register is cleared .
Querying the event register allows you to detect that this conditio n
occurred even if the condition no longer exists. The event register
can only be cleared by querying it or sending the
*CLS
command ,
which clears all event registers .
• Monitor a change in the condition of a particular bit, or bits .
Once you have enabled a bit, the analyzer will monitor it for a
change in its condition . The transition registers are preset to
respond to the condition of going from 0 to 1 (positive transitions) .
This can be changed so that the selected bit is detected if it goes fro m
1 to 0 (negative transition), or if either transition occurs . Query th e
event register to determine whether or not a change has been mad e
to how the transition registers respond . The event register can only
be cleared by querying it or sending the
*CLS
command, which clears
all event registers .
Setting and Querying the Status Registe r
See Figure 2-3 . Each bit in a register is represented by a numerica l
value based on its location. This number is sent with the command to
enable a particular bit. To enable more than one bit, send the sum of al l
of the bits involved .
For example, to enable bit 0 and bit 6 of the standard event status
register, you would send the command
*ESE 65
(1 + 64) .
The results of a query are evaluated in a similar way. If the
*STB 2
command returns a decimal value of 140, (140 = 128 + 8 + 4) then bit 7
is true, bit 3 is true, and bit 2 is true .
Figure 2-3 Status Register Bit Values
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