Device Dependent Event And Condition Registers; Operation Complete Definition; Command Timing And Completion - ILX Lightwave OMM-6810B User Manual

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C H A P T E R

Device Dependent Event and Condition Registers

The Event Registers are used to report events which occur during the operation of
the instrument. Events differ from conditions in that events signal an occurrence
once, and are not reset until the Event Register is queried or the 6810B is
powered off. Conditions reflect the current state of the device, and therefore may
change many times during operation. Querying a Condition Register does not
change its contents.

Operation Complete Definition

Note that bit #0 of the Standard Event Status Register contains the Operation
Complete flag (see *OPC, Section 3.5.9). This bit may be used to signal an SRQ
to the controlling software for more efficient, interrupt driven software. Enable the
SRQ by setting bit #0 in the Standard Event Status Enable Register (*ESE) and
bit #5 in the Service Request Enable Register (*SRE). This may be used to
initiate service request routines which depend on the completion of all previous
commands.
The following conditions define "Operation Complete" within the 6810B:
• The controller, which is updating the hardware, is idle.
• No NVRAM (non-volatile random access memory) write cycles are in progress.
• No calibration routines are running.

Command Timing and Completion

This section describes, for each device-dependent command, whether that
command is performed in an overlapped or sequential manner. In other words, it
states whether the next command may begin while this command is being
executed, or if the next command must wait until this command is completed
before its execution begins.
All 6810B device-dependent commands are executed in an overlapped manner,
and the operation complete flag is set after the conditions outlined earlier in this
have been satisfied.
The *WAI (common command) is an example of a sequential command which
forces the next command to wait until the no-operation-pending flag is true. This
is essentially the same as waiting for the OPC flag to become true, because the
no-operations-pending flag is used to set the OPC flag (bit 0 of the Standard
Event Status Register).
In normal operation, the overlapped commands execute faster than would appear
by querying the OPC flag. This is due to the nature of the non-volatile memory
storage process. This is done to ensure that the OPC flag is never set
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 OMM-6810B
G P I B / I E E E 4 8 8 . 2 R E M O T E O P E R A T I O N
Status Reporting