National Instruments AT-MIO-64F-5, User Manual

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Chapter 2 Configuration and Installation
© National Instruments Corporation 2-33 AT-MIO-64F-5 User Manual
tw=50 nsec minimum
DACs update 100 nsec from this point
V
IL
VIH
tw
tw
Figure 2-16. EXTTMRTRIG* Signal Timing
The minimum pulse width allowed is 50 nsec. The DACs are updated within 100 nsec of the
high-to-low edge. There is no maximum pulse width limitation. EXTTMRTRIG* should be
high for at least 50 nsec before going low. The EXTTMRTRIG* signal is one HCT load and is
pulled up to +5 V through a 10 k
W
resistor.
General-Purpose Timing Signal Connections
The general-purpose timing signals include the GATE and OUT signals for the Am9513A
Counters 1, 2, and 5, SOURCE signals for Counters 1 and 5, and the FOUT signal generated by
the Am9513A. Counters 1, 2, and 5 of the Am9513A Counter/Timer can be used for general-
purpose applications, such as pulse and square wave generation, event counting, pulse-width,
time-lapse, and frequency measurements. For these applications, SOURCE and GATE signals
can be directly applied to the counters from the I/O connector. The counters are programmed for
various operations.
The Am9513A Counter/Timer is described briefly in Chapter 3, Theory of Operation . For
detailed programming information, consult Appendix E, AMD Am9513A Data Sheet . For
detailed applications information, consult the Am9513A/Am9513 System Timing Controller
technical manual published by Advanced Micro Devices, Inc.
Pulses and square waves can be produced by programming Counter 1, 2, or 5 to generate a pulse
signal at its OUT output pin or to toggle the OUT signal each time the counter reaches the
terminal count.
For event counting, one of the counters is programmed to count rising or falling edges applied to
any of the Am9513A SOURCE inputs. The counter value can then be read to determine the
number of edges that have occurred. Counter operation can be gated on and off during event
counting.
Figure 2-17 shows connections for a typical event-counting operation in which a switch is used
to gate the counter on and off.