External Trigger; External Clock Input/Output - Measurement Computing us-1208fs User Manual

USB-1208FS User's Guide

External trigger

Parameter
Trigger source
Trigger mode
Trigger latency
Trigger pulse width
Input type
Schmitt trigger
hysteresis
Input high voltage
threshold
Input high voltage limit
Input low voltage
threshold
Input low voltage limit

External clock input/output

Parameter
Pin name
Pin type
Direction
(software-selectable)
Input clock rate
Clock pulse width
Input type
Schmitt trigger
hysteresis
Input high voltage
threshold
Input high voltage limit
Input low voltage
threshold
Input low voltage limit
Output high voltage
Output low voltage
Table 12. External digital trigger specifications
Conditions Specification
External, digital TRIG_IN
Software-selectable Edge sensitive: user configurable for CMOS compatible rising or
falling edge
10 µs max
1 µs min
Schmitt trigger, 47 kΩ pull-down to ground
1.01 V typ
0.6 V min
1.5 V max
2.43 V typ
1.9 V min
3.1V max
5.5 V absolute max
1.42 V typ
1.0 V min
2.0 V max
-0.5 V absolute min
0 V recommended min
Table 13. External clock I/O specifications
Conditions Specification
SYNC
Bidirectional
Output Outputs internal A/D pacer clock. Active on rising edge.
Input (default) Receives A/D pacer clock from external source. Active on rising edge.
50 kHz, maximum
Input mode 1 µs min
Output mode 5 µs min
Schmitt trigger, 47 kΩ pull-down to ground
1.01 V typ
0.6 V min
1.5 V max
2.43 V typ
1.9 V min
3.1V max
5.5 V absolute max
1.42 V typ
1.0 V min
2.0 V max
-0.5 V absolute min
0 V recommended min
4.4 V min (IOH = –50 µA)
3.80 V min (IOH = –8 mA)
0.1 V max (IOL = 50 µA)
0.44 V max (IOL = 8 mA)
23
Specifications