HOME | INF. INVESTIGATORS | RESOURCES | PUBLICATIONS | PEOPLE

Parallel Port-TTL pulses   |  |  Serial Port:ViewPoint
Using The Parallel Port for TTL output

' Put this part early in the   .ebs script:
'--------------------------------------------------------------------------
' User Script
'--------------------------------------------------------------------------
'
Const BASEADDRESS = 888
'   (Verify the Parallet port's address in the control panel first)

Const ON_Trigger   = 255
Const OFF_Trigger  = 0

''''''''''''''''''
' Put this in an inLine to turn it ON
WritePort BASEADDRESS, ON_Trigger

''''''''''''''''''''
'Use this to turn it OFF
WritePort BASEADDRESS, OFF_Trigger





  Serial Communication with ViewPoint


' E-prime inLine code for Sending time markers to Viewpoint Eyetracker through
' a null-modem serial cable
'
' written by Luis Hernandez-Garcia at U-M
' with help from Valur Olafsson and Arrington Tech.
'
' You need the following to synch. e-prime with ViewPoint:
' - a null modem (cross-over) serial cable from COM port IFIS to COM port on Viewpoint
' - this code inserted as two inLines in the e-prime script
' - On viewPoint:  Interface | Serial port | Connection Settings :
'    verify that the settings is consistent with what's in this code:
'    baud rate, parity, stop-bits, ....etc. You can modify the settings,
'    just make sure both machines are running the same serial protocol
' - Interface | Serial Port | Reset Packet Counter
'
'    When this is all done, you
'    are ready to open a new file on VIewPoint
'    (note that this can also be done
'    through serial port commands)
'    and run your e-prime script.
'
' Note:
' - This code doesn't work on ViewPoint 2.7.1.1
' (you have to send full command strings for that), but has been
' successfully tested in ViewPoint 2.7.1.95 (beta?)
'

'''''''''''''''Begin Code

' Do this section before the block starts (before RF trigger):
' This is is the Packet that we'll send to ViewPoint:
const header as string = "VP"
Dim headerBytes(1) As Integer
headerBytes(0) = 2  ' This specifies the type of string (2=Marker)
headerBytes(1) = 1  ' This specifies the number of bytes
const commandString as string = "M"  'This is the string


' initialize the serial port by creating a
' serialdevice object and setting its properties
dim myPort as SerialDevice
Set myPort = New SerialDevice
dim myPortInfo as SerialDeviceInfo
myPortInfo.CommPort = 2
myPortInfo.BaudRate = 57600
myPortInfo.DataBits = 8
myPortInfo.Parity = ebParityNo
myPortInfo.StopBits = ebStopBits1_0

'Open the port and flush the buffer
myPort.open myPortInfo
myPort.FlushOutBuffer

' End section...Port is now ready to send the packet
''''''''''''''''''''''''''''''''''''''''''''''''''''

' Put the section below as an inLine wherever you want the marker

' Write the packet  itself
myPort.WriteString header  'Header string
myPort.WriteBytes headerBytes,2  'header bytes
myPort.WriteString commandString  ' string
myPort.WriteString chr$(0)  'Null terminator on the string
myPort.FlushOutBuffer

' close the port and clear the object when you are finished
' (when the last packet has been sent)
myPort.close
Set myPort = Nothing
''''''''''''''''''''''''''''''''