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

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Configuration and Installation Chapter 2
AT-MIO-64F-5 User Manual 2-30 © National Instruments Corporation
Power Connections
Pins 34 and 35 of the MIO subconnector p5 V from the PC power supply. These pins
are referenced to DIG GND and can be used to power external digital circuitry.
Power rating 1.0 A at +5 V ± 10%, fused
Warning: Under no circumstances should these +5-V power pins be directly connected to
analog or digital ground or to any other voltage source on the AT-MIO-64F-5 or
any other device. Doing so can damage the AT-MIO-64F-5 and the PC. National
Instruments is
not liable for damages resulting from such a connection.
Timing Connections
Pins 36 through 50 of the MIO subconnector are connections for timing I/O signals. Pins 36
through 40 and pin 44 carry signals used for data acquisition timing and analog output triggering.
These signals are explained in the next section,
Data Acquisition Timing Connections . Pins 41
through 50 carry general-purpose timing signals and analog output provided by the onboard
Am9513A Counter/Timer. These signals are explained in the
General-Purpose Timing Signal
Connections section later in this chapter.
Data Acquisition and Analog Output Timing Connections
The data acquisition and analog output timing signals are SCANCLK, EXTSTROBE*,
EXTTRIG*, EXTGATE*, EXTCONV*, and EXTTMRTRIG*.
SCANCLK Signal
SCANCLK is an output signal that generates a low-to-high edge whenever an A/D conversion
begins. SCANCLK pulses only when scanning is enabled on the AT-MIO-64F-5. SCANCLK is
normally low and pulses high for approximately 4 µsec after the A/D conversion begins. The
low-to-high edge can be used to clock external analog input multiplexers. The SCANCLK
signal is driven by one CMOS TTL gate.
EXTSTROBE* Signal
A low pulse of no less than 500 nsec is generated on the EXTSTROBE* pin when the External
Strobe Register is accessed. See the
External Strobe Register section in Chapter 4, Register Map
and Descriptions , for more information. Figure 2-13 shows the timing for the EXTSTROBE*
signal.
tw>500 nsec
VOH
tw
V
OL
-
Figure 2-13. EXTSTROBE* Signal Timing