Chapter 2 Configuration and Installa tion
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National Instruments Corporation 2-31 AT-MIO-16X User Manual
Digital I/O Signal Connections
The digital lines ADIO<0..3> are connected to digital I/O port A. The
digital lines BDIO<0..3> are connected to digital I/O port B. DIG GND
is the digital ground pin for both digital I/O ports. Ports A and B can be
programmed individually to be inputs or outputs.
The following specifications and ratings apply to the digital I/O lines.
Absolute maximum voltage input rating 5.5 V with respect to
DIG GND
Digital input specifications (referenced to DIG GND):
VIH input logic high voltage 2 V minimum
VIL input logic low voltage 0.8 V maximum
IIH input current load,
logic high input voltage 40 µA maximum
IIL input current load,
logic low input voltage –120 µA maximum
Digital output specifications (referenced to DIG GND):
VOH output logic high voltage 2.4 V minimum
VOL output logic low voltage 0.5 V maximum
IOH output source current,
logic high 2.6 mA maximum
IOL output sink current, logic low 24 mA maximum
With these specifications, each digital output line can drive 11 standard
TTL loads and over 50 LS TTL loa ds .
Figure 2-12 depicts signal connections for three typical digital I/O
applications.