ADLINK USB-2405 - Manual (Page 45)

Operation 35
USB-2405
Figure 3-7: Above-High Analog Triggering
External Digital Triggering
An external digital trigger occurs when a rising or falling edge is
detected on the digital signal connected to the GPIO pin. Trigger
polarity can be programmed using ADLINK software drivers.
Figure 3-8: Digital Triggering
Trigger Modes
Analog input supports post, delay, middle, gate, post trigger with
retrigger, and delay trigger with retrigger modes.
NOTE: NOTE:
Signal level of the external digital trigger signals should be
3/3V/TTL-compatible, with a minimum pulse of 20ns.
Positive-edge
(rising) trigger event
occurs
Negative-edge
(falling) trigger
event occurs