Neurotechnology Research Systems
© Plexon Inc
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The digital inputs can be operated in two different modes. To select the mode, click the drop down
menu next to DI Mode at the top of the screen.
The first mode is called Edge mode. In this case, a rising edge on the start pin initiates stimulation,
and a rising edge on the corresponding stop pin stops stimulation. If the stop input comes in the
middle of a stimulation pattern, the pattern will be cut short. Stimulation will also stop if the
pattern plays to completion. This is illustrated below.
The second mode is called Level mode. In this mode, the stimulation pattern starts when the Start
input transitions from 0 to 1, and continues until the pattern is complete or the Start input
transitions from 1 to 0. This is illustrated below.
As before, if the Start digital input goes low in the middle of a pattern, the pattern will be cut short.
A start signal that occurs after a pattern has been cut short will resume playback of the pattern.
When a stimulation pattern plays to completion, the Radiant software will automatically re-load the
pattern in preparation for another start signal. However, the process of detecting the end of the
pattern and re-loading the pattern takes some time and it may be on the order of 100 ms before the
pattern is ready to be triggered again.
There are two ways to set the polarity of the digital inputs: Positive and Negative. These can be
accessed from the drop down menu DI Polarity at the top of the screen.
In Positive mode, the controller responds to a rising edge if the inputs are in edge mode, or to a
logic 1 in level mode. This is the more common method of communicating through TTL. In
Negative mode, the controller responds to a falling edge if the inputs are in edge mode, or to a logic
On
Current/Voltage Output
Start (Level Trigger Mode)
On
Current/Voltage Output
Start (Edge Trigger Mode)
Stop (Edge Trigger Mode)