Digital I/O - Measurement Computing USB-1208HS-2AO User Manual

USB-1208HS-2AO User's Guide
You can connect an external clock signal to

When using an external clock,
pulse generated from

When using the internal clock,
clock.

Digital I/O

You can connect up to 16 digital I/O lines to screw terminals
resistors that you can configure for pull-up or down using an internal jumper. The default configuration is
pull-down.
You can use the digital I/O terminals to detect the state of any TTL-level input. Refer to the schematic shown in
Figure 7. If you set the switch to the +5 V input, DIO0 reads TRUE (1). If you move the switch to GND, DIO0
reads FALSE (0).
Figure 7. Schematic showing switch detection by digital channel DIO0
Pull-up/down configuration
Each of the 16 DIO bits on the USB-1208HS-2AO has a 47 kΩ pull-up/pull-down resistor. To configure these
bits for either a +5 V pull-up or a 0 V pull-down option, open the device case to access the jumper labeled
The pull-up/pull-down voltage is common to all of the internal 47 kΩ resistors.
Complete the following steps to set the W34 jumper:
1. Turn over the USB-1208HS-2AO and rest it on its top on a flat, stable surface.
2. Peel off the four rubber feet on the bottom of the module to access the screws.
3. Remove the four screws shown in Figure 8 from the bottom of the device.
Figure 8. Location of screws connecting bottom and top sections of case
4. Holding both the top and bottom sections of the module, turn it back over, rest it on the surface, and
carefully remove the top section of the case.
5. Set the jumper to either pull-up or pull-down (see Figure 9 and Figure 10).
and/or
AICKI
AICKO outputs the pulse generated from
AOCKI
outputs the ADC scan clock, and
AICKO
.
AOCKI
AOCKI
AOCKO
DIO0 through DIO15
13
Functional Details
, and AOCKO outputs the
outputs the DAC scan
. The terminals have 47 kΩ
W34 .