National Instruments AT E Series

Chapter4 ConnectingSignals

©NationalInstruments Corporation 4-43 ATE Series User Manual

Whenusing an external UPDATE signal, you must apply at least one more

externalupdate pulse than the number of points that you want to generate.

Thisis necessary for proper hardware operation, otherwise the devicedoes

not indicate that the waveformgeneration is complete.

Figures 4-28 and 4-29 show the input and output timing requirements for

the UPDATE*signal.

Figure4-28. UPDATE* Input Signal Timing

Figure4-29. UPDATE* Output Signal Timing

The DACsare updated within 100 ns of the leading edge. Separate the

UPDATE*pulses with enough time that new data can be written to the

DAClatches.

TheAT E Series device UI counter normally generates the UPDATE*

signalunless you sel ect some external source. The UI counter is started by

the WFTRIG signal and can be stopped by softwareor the internal Buffer

Counter.

D/A conversionsgenerated by either an internal or external UPDATE*

signald o not occur when gated bythe software command register gate.

Rising-Edge

Polarity

Falling-Edge

Polarity

tw=10 ns minimum

tw=300 to 350 ns