HP 8920B, Programmer'S Manual

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Chapter 5, Advanced Operations
HP-IB Service Requests
Procedure for Generating a Service Request
The following steps outline a generalized procedure for properly setting up the
Test Set to generate a Service Request (SRQ) message to the Active Controller.
This procedure does not include instructions for setting up the Active
Controller to respond to the Service Request message generated by the Test
Set. Refer to the operating and/or programming manuals for each controller for
information describing the controller’s capability to set up and respond to SRQ
interrupts.
For register groups with Condition Registers and Transition Filters start at step 1.
For register groups with no Condition Register or Transition Filters start at step 5.
1. Determine which conditions, as defined by their bit positions in the Register Group
Condition Register, should cause the Summary Message to be set TRUE if they oc-
cur.
2. Determine the polarity of the bit-state transition which will indicate that the condi-
tion has occurred.
3. Set the Register Group Transition Filters to the correct polarity to pass the bit-state
transition to the Event Register.
4. Go to step 6.
5. Determine which conditions, as defined by their bit positions in the Register Group
Event Register, should cause the Summary Message to be set TRUE if they occur.
6. Set the correct bits in the Register Group Enable Register to generate the Summary
Message if the condition has been latched into the Register Group Event Register.
7. If the Summary Message is a bit in a Register Group that is not the Status Byte Reg-
ister go to step 1.
8. Set the correct bits in the Service Request Enable Register for all Register Group
Summary Messages selected in steps 1 through 6.