.. _parallelout: Parallel Port Out Component --------------------------------- This component allows you to send triggers to a parallel port, USB2TTL8, or LabJack U3 device. An example usage would be in EEG experiments to set the port to 0 when no stimuli are present and then set it to an identifier value for each stimulus synchronised to the start/stop of that stimulus. In that case you might set the `Start data` to be `$ID` (with ID being a column in your conditions file) and set the `Stop Data` to be 0. Properties ~~~~~~~~~~~ Name : string Everything in a |PsychoPy| experiment needs a unique name. The name should contain only letters, numbers and underscores (no punctuation marks or spaces). Start : The time that the stimulus should first appear. See :ref:`startStop` for details. Stop : Governs the duration for which the stimulus is presented. See :ref:`startStop` for details. Data ==== What information to save, how to lay it out and when to save it. Start data : 0-255 When the start time/condition occurs this value will be sent to the parallel port. The value is given as a byte (a value from 0-255) controlling the 8 data pins of the parallel port. Stop data : 0-255 As with start data but sent at the end of the period. Sync to screen : boolean If true then the parallel port will be sent synchronised to the next screen refresh, which is ideal if it should indicate the onset of a visual stimulus. If set to False then the data will be set on the parallel port immediately. Hardware ======== Parameters for controlling hardware. Port address : select the appropriate option You need to know the address of the parallel port you wish to write to. The options that appear in this drop-down list are determined by the application preferences. You can add your particular port there if you prefer. Register : U3 register to write to When using a LabJack U3, you can select which register is used to write a data byte to. Register EIO is the default. .. seealso:: API reference for :class:`~psychopy.hardware.labjacks.U3`