A question about parallel-port and sending triggers

Hi,

We are working with an EEG system that requires 2 computers that are connected with a parallel-port, so the experiment computer sends triggers (marking stimuli onset) to the port. This is done with an additional toolbox (that doesn't give detailed enough error massages). Recently we upgraded our OS to Windows10 and our MatLab version to MatLab 2017a Network 64bit (for Windows), and since then the experiment computer fails to send the triggers. In order to understand whether the problem lies in the script or the computer, we wanted to ask; Is MatLab 2017a capable of sending triggers to any parallel-port, or only to ones that their address starts with 378? (If you have any other suggestions for a solution, we would be glad to hear them)

Thanks,

Tamar

Answer 1

[Yigit Tuncel]

The problem is due to upgrading your OS, not your Matlab version. Windows 10 is not accessible as Win XP (I presume this is what you used earlier?) or unix. Anyways, you have to use a an external MEX file utility that is able to control the parallel port registers on win10. One such utility can be found at this link . I have successfully used this one along with psychtoolbox to design a time critical experiment in the past on a windows 10 machine. Hope this helps.

[Lina Skora]

Hi Yigit,

I have a similar problem and also tried to use MEX to control the parallel port, but it doesn't seem to communicate with the external device I need to send triggers to (Biopac) at all. Do you happen to know why? I'm using 64bit Windows7, matlab 2017b, and an parallel port add-on board which I suspect might be an issue but I'm not entirely sure.

Thanks!

[Christiana Westlin]

Hi Lina,

Were you able to figure this out? I am having the same issue.

Thanks! Christi

[Yigit Tuncel]

Hi Lina,

The external addon board is most likely the issue in your case. I have used the io64 utility with a Motherboard that has parallel port i/o without encountering any problems, so I can verify it works under win 10 64bit. In fact I also happened to use this setup with a Biopac product with no problems. I would first check the output voltage values and try to figure out the delays (due to converting to TTL) to understand if the addon board messes the communication up.

Good luck, Yigit

[Kate Maresh]

Hi Yigit Sorry to jump onto this thread now but I am fairly new to this and am struggling to set up a trigger from Matlab/Psychtoolbox script to a Biopac unit. I have the STP100 parallel port module and a USB/parallel cable from the script laptop. Is the Mex file script the best way to do this with psychtoolbox and would it work using this type of connection?

Many thanks, Kate

Answer 2

[Leila Azizi]

Hello,

I am trying to send triggers via the parallel port under Linux.

I tested ppdev-mex from https://github.com/widmann/ppdev-mex. Here is my code:

ppdev_mex('Open', 1);
lptwrite(1, 255)
ppdev_mex('Close', 1) ;

The problem is that I don't get an error, but nothing happens. In Python, I can send the trigger via the port:

 PORT1 = '/dev/parport1'

Do you have any idee?