Counter Input; Trigger Input; Sync I/O; Calibration Output - Measurement Computing usb1608fs User Manual

USB-1608FS User's Guide
The user-configurable jumper is labeled
board.
5. Configure the jumper for pull-up or pull-down, as shown in Figure 6.
6. Replace the top section of the housing, and fasten it to the bottom section with the three screws.
For more information on digital signal connections
For general information regarding digital signal connections and digital I/O techniques, refer to the Guide to
Signal Connections (available on our web site at www.mccdaq.com/signals/signals.pdf).

Counter input

The terminal is a 32-bit event counter that can accept frequency inputs up to 1 MHz. The internal counter
CTR
increments when the TTL levels transition from low to high.

Trigger input

The terminal is an external digital trigger input. The trigger mode is set for edge sensitive, and is
TRIG_IN
configurable for rising or falling edge. On power up and reset the trigger mode is set for rising edge.

SYNC I/O

The SYNC terminal is a bidirectional I/O signal that can be configured as an input (default) or an output.

Configure as an external clock input to externally source the A/D conversions. The SYNC terminal
supports TTL-level input signals of up to 50 kHz.

Configure as an output to pace conversions on a second USB-1608FS device and acquire data from
16 channels. For more information about synchronized operations see page 17.

Calibration output

The terminal is an output that is used to calibrate the USB-1608FS. Do not use this pin for any other
CAL
purpose. Calibration is software-controlled by InstaCal.
. Figure 5 shows the location of the jumper on the circuit
DIO
Figure 5. Pull-up/down jumper location
Figure 6. Pull-up/down jumper configuration
13