7-6
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Section Topics
2308-900-01 Rev. A / July 2008
Section 7: Status Structure
Model 2308 Portable Device Battery/Charger Simulator User’s Manual
Figure 7-2
Status byte and service request
Status byte register
The summary messages from the status registers and queues are used to set or clear the
appropriate bits (B0, B2, B3, B4, B5, and B7) of the status byte register. These summary bits do
not latch, and their states (0 or 1) are solely dependent on the summary messages (0 or 1). For
example, if the standard event register is read, its register will clear. As a result, its summary
message will reset to 0, which in turn will reset the ESB bit in the status byte register.
The bits of the status byte register are described as follows:
•
Bit B0, measurement status (MSB)
- Set summary bit indicates that an enabled
measurement event has occurred.
•
Bit B1
- Not used.
•
Bit B2, error available (EAV)
- Set summary bit indicates that an error or status message is
present in the error queue.
•
Bit B3, questionable summary bit (QSB)
- Set summary bit indicates that an enabled
questionable event has occurred.
•
Bit B4, message available (MAV)
- Set summary bit indicates that a response message is
present in the output queue.
•
Bit B5, event summary bit (ESB)
- Set summary bit indicates that an enabled standard
event has occurred.
Status Summary Messages (6)
OSB
(B7)
RQS
(B6)
MSS
ESB
(B5)
MAV
(B4)
QSB
(B3)
EAV
(B2) (B1)
(B0)
OR
* SRE
* SRE?
Status Byte
Register
Service Request
Enable Register
OSB = Operation Summary Bit
MSS = Master Summary Status
RQS = Request for Service
ESB = Event Summary Bit
MAV = Message Available
QSB = Questionable Summary Bit
EAV = Error Available
MSB = Measurement Summary Bit
& = Logical AND
OR = Logical OR
OSB
(B7) (B6)
ESB
(B5)
MAV
(B4)
QSB
(B3)
EAV
(B2) (B1)
(B0)
&
&
&
&
&
MSB
MSB
&
128
(2
7
)
32
(2
5
)
16
(2
4
)
8
(2
3
)
4
(2
2
)
1
(2
0
)
Decimal
Weights
* STB?
Serial Poll
Service
Request
Generation
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