LPT Port Element

Summary ¶

	LPT Port
Info
Category:	Communication		AddIn:	Base Elements
Creator:	OkazoLab		Scope:	Parent event
Owns Snippets:	None		Usage:	Snippets

Properties ¶

Name	Description	Constraints	Type	On runtime change
Port Settings
Base Address	Defines the base address the LPT port, for example 0x0378 (888)	Design Time..	Int32
Working Mode	Defines a working mode for the element.Select the 'AutoOutput on event onset' mode for sending signals synchronously with an onset of the parent event,or 'Triggering on input' mode for catching the particular pattern in port input. For custom reading/writing scenarios use the 'Manual IO' mode, in which port communication can be controlled by your code.	Design Time..	stPara..
Input
Test Input	Open a input monitor window showing real-time port input with the current settings. Use for testing at designtime.	Design Time..	Boolean
Input Value	Returns the current state of the port input lines. The property is updated automatically only in the Triggering Input mode. The value can be read either to the integer or binary formats, e.g. 'string S=Input;' may return '01010101'	Status..	clBina..
Triggering Value	When the element is in the 'Triggering input' working mode, a value of this property defines the 'catching' input pattern in the binary format. If the pattern is detected in port input at any time, the element registers the detection time and becomes triggered. The Triggering Input has to be defined for each of the port line, e.g. '1111****' can be used for detection of the ON state in the first 4 lines of a 8-bit port. Use either '0' or '1' chars for the relevant lines and and the '*' char for irrelevant. Set all lines to *, if you want to detect any change in the port input.	Normal..	String
Trigger Once	Defines whether the element can be triggered multiple times, while the parent event is active. If the property value is 'true' only the first triggering is registered	Design Time..	Boolean
Output
Signal Profile	Defines the time-amplitude profile of the output signal.'Level Change', 'Pulse' and 'TTL' profiles are available	Design Time..	stPara..
Preface Duration	Defines the duration (ms) of the guarantied zero preface interval for the TTL or Pulse signals. Increase the preface duration marginally, if your recording hardware does not detect port signals. Note that a non-zero preface delays the onset of the actual signal.	Normal..	Double
Pulse Duration	Duration of a single output pulse in ms. The value is applied only if the Pulse signal profile is selected	Normal..	UInt64
Interpulse Duration	Defines a duration of the inter-pulse interval in ms. The value is applied only if the Pulse  signal profile is selected	Normal..	clTime
Pulse Number	Defines a number of pulses in the pulse train. The value is applied only if the Pulse signal profile is selected	Normal..	Int32
Output Value	Value to be sent through the port. Can be defined in integer or binary format, e.g. Output='01010000'; or Output=255;	Normal..	clBina..
Send Output Now	Runtime action initiating an instant output communication through the port. Call this action in snippets by 'SendNow=true;', but only if the element works in the 'Manual I/O' mode.	Runtime Command..	Boolean
Runtime Status
Is Triggered	Indicates whether the element has been triggered at least once since activation of the parent event.Triggering occurs only in the 'Input Detection' working mode	Normal..	Boolean
Triggering Time	Indicates the local event time of the last element triggering. Triggering occurs only in the 'Input Detection' working mode.	Status..	clTime
Control
Is Enabled	If set to false the element is completely omitted when the experiment is run	Design Time..	Boolean
Title	Title of the element	Design Time..	String

¶

Description ¶

Snapshots ¶

Practical Use ¶

• Add LPT Port element to your stimulus event.
• Select the 'Auto-output on event onset' working mode for the created element.
• Select the proper signal profile. For example, most of EEG recording stations recognize the Pulse signals with a short duration, e.g. 5 ms. You can test what signal profile works best on your hardware, by probing the probe output with Test Output Now action (in element properties). If you use the pulse signal, don't forget to define its duration via the Pulse Duration property.
• Create a proxy variable linked to the Output property of the element.
• Choose any snippet that is invoked earlier than the event onset, e.g. Before Onset snippet on the same event
• Write a code line that assigns a stimulus number to the 'Output' proxy variable:
  

  
  
  Output=Stimulus_Number;
  
  

• That is it! The stimulus number now will be sent precisely on the stimulus onset
  

Working Modes ¶

'Manual I/O' mode ¶

/// Code example on using the LPT Port Element in the 'Manual I/O' mode

//****** Reading the current port input *******
int NewInput=PortInput; // PortInput is a proxy variable linked to the Input property of the LPT Port element

//****** Sending data to port *******
if (N>5)
PortOutput=255; // PortOutput is a proxy variable linked to the Output property of the LPT Port element
else
PortOutput="10101010"; // the output can be also set by a string encoding a binary state for each of 8 port lines
SendNow=true; // initiate actual sending the a new port output, defined by the PortOutput variable

'Output on event onset' mode ¶

1. Level Change | ... → Value If this signal shape is selected, the element just instantly sets the output of a parallel port to a value defined by the Output Value property. The port state persists until the next change.
2. Pulse | ... -> Zero (Preface) → Value → Zero If this signal shape is selected, the element forms the output signal made of 3 parts. Shortly before onset of the parent event, the port is set to the zero. (a preface zero state when all port lines are Off). At the event onset the element instantly changes the port lines to the value defined by the Output property (Value state). Later, after a time interval defined by the Pulse Duration property, the element sets the port output back to the zero. If the pulse duration is greater than the actual duration of the parent event, the element grounds the port on the offset of the the parent event.
3. TTL | ... → Zero (Preface) → Value If this signal shape is selected, the element forms the output signal made of 2 parts. Shortly before onset of the parent event, the element sets the current port output to the ground (zero preface state when all lines are Off). At the event onset the element instantly changes the port output to the value defined by the Output property (HIGH state). The port state persists until the next change.
   

'Triggering on specific input' mode ¶

Notes ¶

1. When the element is in the 'Auto-output on event onset' mode, you have to assign the output value before the event onset. You can assign a value to the Output property in the designer or, if you want to change the value at runtime, in the Before Onset snippet or in any of earlier events.
2. If you need to detect any change in the port input, then use the 'Triggering on specific input' mode with the Triggering Input property set to '********', such that a change in any line would cause the element triggering.
3. For better synchronization of the port output in the 'Auto-output on event onset' mode, move the LPT Port element at the top of the elements list in the parent event. Elements get to work one by one on the onset of the parent event, so the top position in the list guaranties a minimal start-up delay.
4. In the 'Triggering on specific input' mode the element does not get triggered, if the triggering value is already present in the port input on the onset of the parent event. A change of the port line is required to trigger the element.