External Trigger; External Clock Input/Output - Measurement Computing USB-1208FS-Plus User Manual

USB-1208FS-Plus User's Guide

External trigger

Parameter
Trigger source (Note 7)
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
Terminal name
Terminal 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. Digital trigger specifications
Specification
External digital; TRIG_IN terminal
Edge sensitive; software-selectable for CMOS compatible rising or falling edge, high
or low level.
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
3.1 V 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
Condition
Output
Input (default)
Input mode
Output mode
24
Specification
SYNC
Bidirectional
Outputs the internal A/D pacer clock
Receives A/D pacer clock from external source
50 kHz, max
1 µs min
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
3.1 V 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)
Specifications