Specifications

3-19
Interrogating the Instrument Status
Interrupt Programming and Using the Service Request
50 OUTPUT Err_det“STATUS:OPERATION:NTRANSITION 6144”
60 OUTPUT Err_det“STATUS:OPERATION:ENABLE 6144”
70 OUTPUT Err_det“*SRE 128”
80 ENTER Err-det“SENSE1:EYE:TCENter ON”
90 ON INTR 7 CALL Servroutine( Escape )
100 ENABLE INTR 7,2
110 REPEAT
120 PRINT “Data/Clock Aligning”
130 UNTIL Serv=1
140 PRINT “Data/Clock Aligned”
150 END
160 SUB Servroutine( Serv )
170 Serv=1
180 PRINT “Interrupt received”
190 SUBEND
Note that it is necessary to explicitly turn positive transitions OFF when you are setting up
the SRQ conditions (line 40). Lines 50 and 60 cause the STB bit 7 to be set only if bits 11
or 12 are set in the OPERATION register. When both these bits go low, the Data/Clock
alignment is completed and an SRQ is generated.
Use the interrupt occurrence to proceed to the next part of the program.
The time that bit 7 stays high for in the SRE register depends on how long the TCENter
command takes to execute and depends on initial parameter values (phase delay and data
rate for example). For a 2^23−1 PRBS @ 3 Gb/s, 0.5 volts pp, the time is about 10
seconds for TCEN on the unit tested.