5.7 Status System
5-76 ZM2371/ZM2372
5.7.2 Status Byte
The definition of status byte register is shown in Table 5-4. For the status byte register, the
bits that set “1” to the service request enable register become valid, and if even any one of
valid bits is set to “1”, the service request occurs.
The status byte can be read by serial polling or *STB? query. However, bit 6 becomes RQS
(Request Service) when serial polling is used for reading, or MSS (Master Summary Status)
when *STB? query is used.
Table 5–4 Status byte register definitions
Condition for setting to “1”
Condition for resetting to “0”
When any valid bit of the
operation status event register is
set to 1.
・ When device clear was
received
・ After status byte was read
・ When device clear was
received
・ Bit 6 becomes RQS when
status byte was read by serial
polling
・ Bit 6 becomes MSS when
master summary bits were all
cleared to “0”
When any valid bit of the
standard event status register is
set to 1.
When all the valid bits of the
standard event status register are
set to 0.
When the response to the query
is ready to be output.
When all of the responses have
been output and there remains
not to be output.
When two or more bits are “1”, if the content of status byte is queried, the value added with
the weight of all bits that were set to “1” becomes a response message.
About verifying status when querying
Normally, once a query command is transmitted, you can receive the response correctly, if
response message is received. There is no need to check the MAV bit of the status byte.
When a processing is progressed while checking the MAV bit, after the query was
transmitted, check by serial polling that the MAV bit of status byte becomes “1”, and then
read the response message, and after checking that the MAV bit becomes “0”, perform the
next operation.
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