Digital I/O Terminals (Dio0 To Dio7); Digital I/O Control Terminal (Dio Ctl) For Pull-Up/Down Configuration; Ground Terminals (Agnd, Dgnd) - Measurement Computing USB-3102 User Manual

USB-3102 User's Guide

Digital I/O terminals (DIO0 to DIO7)

You can connect up to eight digital I/O lines to the screw terminals labeled
You can configure each digital bit for either input or output.
When you configure the digital bits for input, you can use the digital I/O terminals to detect the state of any
TTL level input. Refer to the switch shown in Figure 8 and the schematic shown in Figure 9. When the switch is
set to the +5 V USER input, DIO7 reads TRUE (1). If you move the switch to DGND, DIO7 reads FALSE (0).
Pin 56
Pin 28
+5V
DIO7
Figure 8. DIO7 detecting the state of a switch
For more information on digital signal connections
For more information on digital signal connections and digital I/O techniques, refer to the Guide to
Signal Connections (available on our web site at www.mccdaq.com/pdfs/DAQ-Signal-Connections.pdf).

Digital I/O control terminal (DIO CTL) for pull-up/down configuration

All digital pins are floating by default. When inputs are floating, the state of unwired inputs are undefined (they
may read high or low). You can configure the inputs to read a high or low value when they aren't wired. Use the
connection (pin 54) to configure the digital pins for pull-up (inputs read high when unwired) or pull-
DIO CTL
down (inputs read low when unwired).

To pull up the digital pins to +5V, wire the

To pull down the digital pins to ground (0 volts), wire the
(pin 50, 53, or 55).

Ground terminals (AGND, DGND)

Eight analog ground (
channels. Three digital ground (
connections.
+5V
Pin 53
DGND
) connections provide a common ground for all analog voltage and current output
AGND
) connections provide a common ground for the
DGND
DGND
Figure 9. Schematic showing DIO7 detecting the state of
DIO CTL terminal pin to the
terminal pin to a
DIO CTL
16
Functional Details
to (pins 21 through 28).
DIO0 DIO7
DIO7
+5V
a switch
+5V terminal pin (pin 56).
terminal pin
DGND
, ,
DIO CTR SYNCLD
and