This article applies to:
E-Prime 3.0
Chronos
Detail
Experiment Author: Psychology Software Tools, Inc.
The Chronos Adapter for g.tec sample experiment illustrates how to use Task Events to send markers from the E-Prime experiment to the g.tec trigger cable.
Abstract
The sample experiment presents a Visual Oddball Task: each trial presents the letter "O" or "X" and the participant's task is to distinguish between these letters. 80% of the trials present the letter "O" and 20% of the trials present the letter "X". The experiment sends the marker value 1 when the letter "O" is shown and the value 128 when the letter "X" is shown.
The Chronos Adapter for g.tec provides access to 8 digital outputs (from Chronos to the g.tec trigger cable) as shown below:
When Chronos sends a marker on its first digital output, the g.tec trigger cable receives the value on bit 0 (pin 1). When Chronos sends a marker on its eighth digital output, the g.tec trigger cable receives it on bit 7 (pin 8). To determine which bit receives the Chronos output, do the following:
- Represent the integer marker being sent as a binary number (see INFO: Choosing a marker value to send from E-Prime to an external device [42529] for more information on integer and binary numbers).
- Map the binary number to Chronos's digital outputs to determine which outputs are set high (set to 1).
- Examine which trigger cable bits map to the Chronos digital outputs that are set high.
For example, the sample sends the integer value 1 when the stimulus = the letter "O":
- Integer value 1 equals the binary number 0000 0001 (Least Significant Bit is right-most bit).
- 0000 0001 sets the first Chronos digital output high; all other digital outputs are low.
- As shown in the table above, the first Chronos Digital Output maps to bit 0.
The sample sends the integer value 128 when the stimulus = the letter "X":
- Integer value 128 equals the binary number 1000 0000.
- 1000 0000 sets the eighth Chronos digital output high; all other digital outputs are low.
- The eighth Chronos Digital Output maps to bit 7.
NOTE: Extract all the files in the attached .zip file to the same folder. The sample experiment displays images that must be located in the same folder as the experiment.
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