Technical data

• Locate the corresponding status register.

• Set the transition filter to pass the chosen transition of that event.

• Set the enable register from that register group to pass that event to set the

summary bit in the Status Byte Register.

• Set the Status Byte Enable Register to generate an SRQ on the chosen summary

bit being set.

Using Interrupts - Procedures

The process of using interrupts is best explained by looking at an example. The

following example generates an SRQ from an event in the Operation Status group.

Specifically, it causes the error detector to generate a service request upon

detection of a bit error. This is done by catching the positive transition of the Serial

BERT's BIT ERR event (bit 8 in the Operation Status register).

Using Interrupts with SCPI

Note that you can only test this example if the error detector is aligned to an

incoming bit stream. For testing purposes, it is recommended that you have

connected the pattern generator's Data Out port to the error detector's Data In

port using a shielded cable and performed an alignment (bit error rate should be

0).

To generate and detect an interrupt upon detection of a bit error:

Reset the instrument.

*RST

Align the error detector to the pulse generator.

SENSe1:EYE:ALIGN:AUTO 1

Reset the status subsystem.

*CLS

Note: This resetting and aligning must be carried out before setup of the

operation and status bytes. Otherwise the errors generated during alignment

would be reflected in the status system.

Set the Operation Status register's transition registers so that the positive

transition of the BIT ERR bit (bit 8) is caught:

STATus:OPERation:PTRAnsition 256

STATus:OPERation:NTRAnsition 0

Note: The default setting of the transition registers is to pass only positive

transitions.

Recommended Programming Techniques 3

Agilent J-BERT N4903B High-Performance Serial BERT 53