Standard BioSemi PArallel Port Cable Incompatibility

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Baris
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Standard BioSemi PArallel Port Cable Incompatibility

Post by Baris »

Dear all,

Have you ever tried sending pulses "FROM" the USB2 Box to the PC by using the 32/25 pin standard biosemi parallel port cable? It looks like it is possible to send pulses "TO" USB2 Box FROM the PC, but not vice versa. Because all the output pins are grounded on the PC side.

ANy experiences? DO I have to order a new cable?

Baris

Coen
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Post by Coen »

The LabVIEW code of ActiView Light (http://www.biosemi.com/download/ActiView604-Light.zip) shows an example of how to sent codes to trigger port (15 lines available).

You will have to make the appropriate cable yourself according to the information on http://www.biosemi.com/faq/trigger_signals.htm

Best regards, Coen (BioSemi)

Baris
Posts: 13
Joined: Thu Apr 16, 2009 3:15 pm
Location: University of Edinburgh

Post by Baris »

I see. But it was very inconvenient for us not to be informed about the fact that we need a new cable. We ordered a response box from BioSemi and logically we expected the cable to be compatible to send triggers from the USB to the PC.

We lost some time to diagnose the source of the problem. We thought it is a software issue. Why don't you provide such cables to your customers instead?

B-

Coen
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Post by Coen »

The provided response box connect to the AD-box. The triggers are directly available in ActiView. Make sure you have set the CFG to see the triggers. The trigger cable is not involved.

I was referring to sending triggers from the acquisition PC to output trigger lines.

Best regards, Coen (BioSemi)

Baris
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Joined: Thu Apr 16, 2009 3:15 pm
Location: University of Edinburgh

Post by Baris »

I think you didn't really understand my point. When you make a response with the response boxes, you are sending the trigger to USB box via the optic cable, and then to the
the ActiViw via USB cable. That is fine.

But, how will you be able to make the experimental computer that is connected to the USB box via Parallel Port to
receive triggers from the Response Boxes?

If you had understood this, you would have provided the correct parallel port cable to the customers who are also ordering response boxes. We
need to respond to the stimulus in order to proceed to the next one
or to change the stimulus type or to record it in the experimenting computer during the experiment. This is very straightforward.

B-

Coen
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Post by Coen »

The answer is above, ActiView should be reprogrammed to sent out triggers, and a special cable should be constructed.

Best regards, Coen

Coen
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Post by Coen »

A special version of ActiView is ready for download from http://www.biosemi.com/download/ActiView606-Lores.zip . This version routes the response signals from input trigger lines 9 and 10 to trigger output lines 1 and 2 (pin 17 and 18, see http://www.biosemi.com/faq/trigger_signals.htm).

Please note this method of routing the triggers via ActiView does not offer exact timing between the moment of actuating a response switch, and the appearance of the output trigger signal. A small varying timing delay (in the order on a few tenths of a second) between switch action and output trigger is cause by the Windows OS controlling the actions of ActiView. In most experimental setups, this should not present a problem.

Best regards, Coen (BioSemi)

Baris
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Joined: Thu Apr 16, 2009 3:15 pm
Location: University of Edinburgh

source code

Post by Baris »

Thanks Coen,

Could you please provide me the source code(s) of the 606-Lores.vi ?
If possible could you please let me know at what module you made the changes on the block diagram?

I appreciate your assistance,
BAris

Coen
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Post by Coen »

A new version of the zip file (same name, now 3.7 Mb) is available on the same link as above, the full source code is now added to the zip.

Follow the "Triggers Boolean" output array from subvi "TrigProcess.vi", and you'll find an added USB_WRITE function call (lower right section of the main diagram). This extra function call writes the triggers to the trigger port on the USB receiver.

Best regards, Coen (BioSemi)

Baris
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Joined: Thu Apr 16, 2009 3:15 pm
Location: University of Edinburgh

Post by Baris »

A colleague has mentioned that the timing variability you refer to |(due to Windows O/S) might be eliminated by running LabView Real Time. Can ActiView be comipled to run in the realtime environment?

Best,
Baris



Baris

Coen
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Post by Coen »

As far as I know, the basic ActiView code can be used. However, the problem with LabVIEW RT is that it needs to run on dedicated real time (National Instruments) hardware. An interface between the ActiveTwo and this special real time hardware is not available at the moment.

An option (using our standard hardware) might be to work with real-time Linux as an alternative for Windows. We have just released a beta version of a new driver set that also supports Linux, see viewtopic.php?t=76 . If our customers express their interest for an ActiView version under Linux, than we will are willing to invest in LabVIEW for Linux.

Best regards, Coen (BioSemi)

Baris
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Joined: Thu Apr 16, 2009 3:15 pm
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Post by Baris »

Hi Coen,

The version ActiView606 successfully worked to transfer the input button presses back to the USB box, which in turn were recognized by the parallel port input to the experimenting PC (pins 17 and 18).

But now we have a minor problem: the other 6 pins (19-24) look like they are also active, and on the Actiview, the triggers 11-16 show traces as if there is continuous triggering. I think when the USB Write works that way, it not only activated pins 17 and 18, but also not ground the rest of the output pins.

I looked at the USB Write function, but couln't figure out how the rest of the pins can be grounded. I appreciate if you can help me to figure this out, becasue I do not want to do physical grounding of the pins 19-24 on the parallel port cable, and most probably this can be achieved through LabView.

Best.
BAris

Coen
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Post by Coen »

The input triggers (pin 1-16) are not coupled by hard- or software to the output triggers 3-15 (pin 19 to pin 31). Pin 32 shows constant activity: the sample clock. So there seem to be two unrelated problems in your case

Constant activity on triggers 11 to 16 may be caused by wrong connections. The pins will not easily pick up spurious signals because of the internal pull-up resistors (10 kOhm). Activity on triggers 9-16 may also be caused by pressing the F1-F8 keyboard buttons (F1-F8 are in ActiView linked to triggers 9-16 in order to set markers in the file).

The output triggers 1-16 are controlled by the 2nd and 3rd byte sent to the USB_WRITE function. You can clearly see in the software that zeros are send for triggers 3-15 for each call of USB_WRITE. So, the triggers are actively held low with the software function you are using. I have confirmed this by monitoring all 15 output triggers on the trigger port with the software running. So, I cannot explain your findings, please check again.

Best regards, Coen

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