Keysight Technologies X-Series, Programming Manual

Page: 175 / 398

Keysight CXG, EXG, and MXG X-Series Signal Generators Programming Guide 175
Programming the Status Register System
Accessing Status Register Information
When a condition changes and that condition has been enabled, the request
service summary (RQS) bit in the status byte register is set. In order for the
controller to respond to the change, the Service Request Enable Register
needs to be enabled for the bit(s) that will trigger the SRQ.
Generating a Service Request
The Service Request Enable Register lets you choose the bits in the Status
Byte Register that will trigger a service request. Send the *SRE <num>
command where <num> is the sum of the decimal values of the bits you want
to enable.
For example, to enable bit 7 on the Status Byte Register (so that whenever the
Standard Operation Status register summary bit is set to 1, a service request is
generated) send the command *SRE 128.
Refer to
Figure 4-1 on page 170 and Figure 4-2 on page 171 for bit positions
and values.
The query command *SRE? returns the decimal value of the sum of the bits
previously enabled with the *SRE <num> command.
To query the Status Byte Register, send the command *STB?. The response will
be the decimal sum of the bits which are set to 1. For example, if bit 7 and bit 3
are set, the decimal sum will be 136 (bit 7 = 128 and bit 3 = 8).
The SRQ process asserts SRQ as true and sets the status byte’s RQS bit to 1.
Both actions are necessary to inform the controller that the signal generator
requires service. Asserting SRQ informs the controller that some device on the
bus requires service. Setting the RQS bit allows the controller to determine
which signal generator requires service.
This process is initiated if both of the following conditions are true:
— The corresponding bit of the Service Request Enable Register is also set to
1.
— The signal generator does not have a service request pending.
A service request is considered to be pending between the time the signal
generator’s SRQ process is initiated and the time the controller reads the
status byte register.
Multiple Status Byte Register bits can assert an SRQ, however only one bit
at a time can set the RQS bit. All bits that are asserting an SRQ will be read
as part of the status byte when it is queried or serial polled.