HP 8920B - Page 262

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Chapter 5, Advanced Operations
Status Reporting
Status Byte Register
The Status Byte Register is an 8-bit register that is used to summarize the
Summary Messages from all the register groups in the Test Set, and the Request
Service (RQS) or Master Summary Status (MSS) messages. The contents of the
Status Byte Register, referred to as the status byte, can be read by the Active
Controller to determine the condition of each of the register groups. The Summary
Message from each register group is assigned to a specific bit position in the
Status Byte Register as shown in
figure 4 . If the Summary Message from a
particular register group is TRUE, logic 1, its assigned bit in the Status Byte
Register will also be TRUE. If the Summary Bit from a particular register group is
FALSE, logic 0, its assigned bit in the Status Byte Register will also be FALSE.
NOTE: A Status Register Group Summary Message Bit may be summarized indirectly to the Status
Byte Register through a Status Register Group which is summarized directly into the Status
Byte Register.
Figure 4 Status Byte Register
Communicate Status Register Group
Operation Status Register Group
Request Service Message
Standard Event Status Register
Output Queue
Questionable Data/Signal Register Group
Unused in HP 8920
Hardware Status Register #2 Group
Calibration Status Register Group
RQS
MSS
6107
Master Summary Status Message
Status Byte Register
Hardware Status Register #1 Group
Read by Serial Poll
Read by STB?
Call Processing Status Register Group
5432
ESB MAV
ch4drw2.ds4