Connect-Tek USB-2 Spécifications télécharger pdf (Page 398)

Status and Events

Use the *SRE com

mand to set the SRER. Use the *SRE? query to read the

read with a Serial Poll or the MSS bit changes back to a zero.

Figure 3-5: The Service Request Enable Register (SRER)

*PSC Command

The *PSC command controls the Enable Registers contents at power-on. Sending

*PSC 1 sets the Enable Registers at power on as follows:

DESER 255 (equivalent to a DESe 255 command)

ESER 0 (eq

uivalent to an *ESE 0 command)

SRER 0 (equivalent to an *SRE 0 command)

Sending *PSC 0 lets the Enable Registers m aintain their values in nonvolatile

memory through a power cycle.

NOTE. T

o enable the PON (Power On) event to generate a Service Request, send

*PSC 0, use the DESe and *ESE commands to enable PON in the DESER and

ESER, and use the *SRE command to enable bit 5 in the SRER. Subsequent

power-on cycles will generate a Service Request.

Queues

Output Queue

The oscilloscope stores query responses in the Output Queue and empties this

que

ue each time it receives a new command or query message after an <EOM>.

The controller must read a query response before it sends the next command (or

query) or it will lose responses to earlier queries.

CAUTION. When a controller sends a query, an <EOM>, and a second query,

the oscilloscope normally clears the ﬁrst response and outputs the second while

reporting a Query Error (QYE bit in the ESER) to indicate the lost response. A

fast controller, however, may receive a part or all of the ﬁrstresponseaswell.To

avoid this situation, the controller should always read the response immediately

after sending any terminated query message or send a DCL (Device Clear) before

sending the second query.

Event Queue

The Event Queue stores detailed information on up to 128 events. If more than

128 events stack up in the Event Queue, the 128th event is replaced by event

code 350, "Queue Overﬂow."

3-4 MSO2000B, DPO2000B, MSO2000 and DPO2000 Series Oscilloscopes Programmer Manual

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Connect-Tek USB-2 Spécifications Page 398