Measurement Computing USB-1616FS - Manual (Page 25)

USB-1616FS User's Guide Specifications
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Digital input/output
Table 7. Digital I/O specifications
Digital type CMOS
Number of I/O 8 (DIO0 through DIO7)
Configuration Independently configured for input or output
Pull up/pull-down configuration All pins pulled up to USB VBUS via 47 kΩ resistors (default). Positions are
available for pull-down to ground (GND). Hardware selectable via 0 Ω
resistors is available as a factory option.
Digital I/O transfer rate (software paced) System dependent, 33 port reads to 1000 port reads/writes or single bit
reads/writes per second, typ
Input high voltage 2.0 V min, 5.5 V absolute max
Input low voltage 0.8 V max, –0.5 V absolute min
Output high voltage (IOH = –2.5 mA) 3.8 V min
Output low voltage (IOL = 2.5 mA) 0.7 V max
Power on and reset state Input
External trigger
Table 8. External trigger specifications
Parameter Conditions Specification
Trigger source (Note 3) External digital TRIG_IN
Trigger mode Software selectable Edge Sensitive: user configurable for CMOS
compatible rising (default) or falling edge.
Trigger latency 10 µs max
Trigger pulse width 1 µs min
Input high voltage 4.0 V min, 5.5 V absolute max
Input low voltage 1.0 V max, –0.5 V min
Input leakage current ±1.0µA
Note 3: TRIG_IN is a Schmitt trigger input protected with a 1.5 k Ohm series resistor.
External clock input/output
Table 9. External clock I/O specifications
Parameter Conditions Specification
Pin name SYNC
Pin type Bidirectional
Software selectable direction Output Outputs internal A/D pacer clock.
Input Receives A/D pacer clock from external source.
Rising edge sensitive.
Input clock rate 50 kHz, max
Clock pulse width Input 1 µs min
Output 5 µs min
Input leakage current ±1.0 µA
Input high voltage 4.0 V min, 5.5 V absolute max
Input low voltage 1.0 V max, -0.5 V absolute min
Output high voltage (Note 4) IOH = –2.5 mA 3.3 V min
No load 3.8 V min
Output low voltage (Note 4) IOL = 2.5 mA 1.1 V max
No load 0.6 V max
Note 4: SYNC is a Schmitt trigger input and is over-current protected with a 200 Ω series resistor.