HP 8920B - Page 263

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Chapter 5, Advanced Operations
Status Reporting
Table 16 details the Status Byte Register bit assignments and their associated
meaning.
The Status Byte Register is unique in that bit 6 can take on two different
meanings. The contents of the Status Byte Register can be read two ways: by
using a serial poll, or by using the *STB? Common Command. Both methods
return the status byte message, bits 0-5, and bit 7, as defined in table 16. The value
sent for bit 6 is, however, dependent upon the method used.
Table 16 Status Byte Register Bit Assignments
Bit
Number
Binary
Weighting
Condition Comment
7 128 Operation Status Register
Group Summary Message
1= one or more of the enabled events have
occurred since the last reading or clearing of
the Event Register
6 64 Request Service (RQS) when
read by serial poll OR Master
Summary Status message
when read by *STB?
command
1= Test Set has requested service
OR
1= one or more of the enabled service request
conditions is true
5 32 Standard Event Status Bit
(ESB) Summary Message
1= one or more of the enabled events have
occurred since the last reading or clearing of
the Event Register
4 16 Output Queue Message
Available (MAV) Summary
Message
1= information is available in the Output
Queue
3 8 Questionable Data/Signal
Register Group Summary
Message
1= one or more of the enabled events have
occurred since the last reading or clearing of
the Event Register
2 4 Unused in Test Set
1 2 Hardware #2 Status Register
Group Summary Message
1 = one or more of the enabled events have
occurred since the last reading or clearing of
the Event Register
0 1 Hardware #1 Status Register
Group Summary Message
1 = one or more of the enabled events have
occurred since the last reading or clearing of
the Event Register