National Instruments AT-MIO-16D, User Manual, Page: 59 / 291

Configuration and Installation Chapter 2
AT-MIO-16D User Manual 2-38 © National Instruments Corporation
t
w
50 nsec minimum
V
IL
V
IH
t
w
t
w
First A/D conversion starts within
one sample interval from this point
Figure 2-35. START TRIG* Signal Timing
The minimum allowed pulse width is 50 nsec. The first A/D conversion starts within one sample
interval from the high-to-low edge. The sample interval is controlled by Counter 3.
There is no maximum pulse width limitation; however, START TRIG* should be high for at least
50 nsec before going low. The START TRIG* signal is one LS TTL load and is pulled up to +5
V through a 4.7-k
Ω
resistor.
The STOP TRIG pin is used during AT-MIO-16D pretriggered data acquisition operations. In
pretriggered mode, data is acquired but no sample counting occurs until a rising edge is applied to
the STOP TRIG pin. This causes the sample counter to then start counting conversions. The
acquisition then completes when the sample counter decrements to zero. This mode acquires data
both before and after a hardware trigger is received. Figure 2-36 shows the timing requirements
for the STOP TRIG signal.
t
w
50 nsec minimum
First sample counting occurs within
one sample interval from this point
t
w
t
w
V
IL
V
IH
STOP TRIG
Figure 2-36. STOP TRIG Signal Timing
The STOP TRIG signal is one LS TTL load and is pulled up to +5 V through a 4.7-k
Ω
resistor.
General-Purpose Timing Signal Connections
The general-purpose timing signals include the GATE, SOURCE, and OUT signals for the
Am9513A Counters 1, 2, and 5, and the FOUT signal generated by the Am9513A. Counters 1, 2,