Tektronix 070-9180-01 Computer Hardware User Manual


 
Status and Events
Option 01 VXI Interface Module User Manual
4–3
Table 4–2: The Service Request Enable Register (Cont.)
Bit Function
Decimal
Value
3 8 Not used
4 16 Message Available Bit indicates that a service request will be
generated when a message is placed in the Output queue.
5 32 Event Status Bit indicates that events summarized in bit 5 of the
Status Byte register will generate a service request.
6–7 Not used
If, for example, the *SRE? query returns a value of 48, bits 4 and 5 are set in the
Service Request Enable register. Any event that causes the Message Available bit
(bit 4) or Event Status bit (bit 5) to be set in the Status Byte register now
generates an interrupt. If you want an interrupt to be generated only when the
Event Status bit (bit 5) is set, use the *SRE 32 command.
The Standard Event Status register, shown in Table 4–3, records many types of
events that can occur in the Option 01. Use the *ESR? query to read the contents
of this register. The response is the sum of the decimal values for all bits set.
Reading this register clears all bits so the register can accumulate information
about new events.
Table 4–3: The Standard Event Status Register
Bit
Decimal
Value
Function
0 1 Operation Complete shows that the operation is complete. This bit
is set when all pending operations complete following a *OPC
command.
1 Not used
2 4 Query Error shows that data in the Output queue was lost.
3 8 Not used
4 16 Execution Error shows that an error occurred while the Option 01
was executing a command or query. Table 4–6 on page 4–7 lists
the execution error messages.
5 32 Command Error shows that an error occurred while the Option 01
was parsing a command or query. Table 4–5 on page 4–6 lists the
command error messages.
6 Not used
7 128 Power On shows that the Option 01 was powered on.
Standard Event Status
Register