ADLINK PXI-2006 - Manual (Page 74)

64 Operation Theory
should be TTL-compatible and the minimum pulse width
is 20ns.
5. DA_TRIG, the trigger signal for the D/A operation, which
could be derived from external digital trigger, analog trig-
ger, internal software trigger and SSI_AD_TRIG. Refer to
Section 4.5 for detailed de-scription.
6. DAWR, the update signal to initiate a single D/A conver-
sion, which could be derived from internal counter, AFI[1]
or SSI_DAWR. Note that this signal is edge-sensitive.
When using AFI[1] as the external DAWR source, each
rising edge of AFI[1] would bring an effective update sig-
nal. Also note that the AFI[1] signal should be TTL-com-
patible and the minimum pulse width is 20ns.
Auxiliary Function Inputs (AFI)
Users could use the AFI in applications that take advantage of
external circuitry to directly control the DAQ/PXI-2000 series
cards. The AFI in-cludes 2 categories of timing signals: one group
is the dedicated input, and the other is the multi-function input.
Table 4-9 illustrates this categorization.
Table 4-9 summarizes the auxiliary function input signals and the
corre-sponding functionalities