interfacing trigger from RS-232 with E-Prime

Does anybody have any experience detecting the trigger signal from the serial port with e-prime? I’m trying to set up an e-prime program that will loop infinitely until the trigger is detected, however I have yet to get it to work (admittedly also I’m not sure I’ve got the right port and pin numbers).

We have the LSC-400B controller box in the lab.

Thanks in advance.

Assuming that you also have the Lumina response pad, try having E-Prime detect key presses – this is an easier way to test the setup such as baud rate, COM port number, etc.

Once E-Prime can detect the buttons, from E-Prime’s perspective the trigger is simply the 5th button.

I’m not sure if we have a Lumina response pad. I’ll go take a look the next time I get a chance to go to the MRI lab.

So does this mean it’s not possible to simply connect the LSC-400B controller box to the computer via serial port and interface it through e-prime? Also does this mean the controller box actually sends an ASCII message through the serial port or does it just change the voltage in certain pins?

Yes, you can connect the controller directly to a computer via serial port. Using the response pad was just an idea to help you with the testing but it’s not required.

When set to E-Prime mode, the controller sends 800 or 1600 bytes per second, with each byte containing a bit pattern and each bit corresponding to a key. That’s how PST implemented it in their Serial Response Box (SRB) and the Lumina controller emulates that. When using the Lumina controller with E-Prime, you should be telling E-Prime that you have a PST SRB Model 200A.

It is possible to have the Lumina controller send ASCII characters – just set the mode to ASCII. But in this case, you will need to do some programming in E-Prime to open the serial port and read the incoming bytes.

Okay so it sounds like I will have to change my approach to the problem. Originally the e-prime script looked something like this when we were using the parallel port:

scan = readport(&H379)
scan = scan and &H40
loop while scan <> &H40

To use the serial port, I thought I could just change the port to &H3F8 then change the pin number (which I have no idea how to find…yet). So it sounds like it isn’t as simple as I once thought?

Alas, I don’t know E-Prime to be able to help with this question. Is your sample code meant to “talk” to a generic serial device? My understanding is that you can simply tell E-Prime that you are using a PST Serial Response Box Model 200A, set the baud rate and COM port number correctly, and it should work – no serial port scripting necessary.

Actually I got it to work via the serial port scripting. But you are right. I just found out we had a PST Serial Response Box so I’m going to be testing that out. The problem before with the scripting is that I can’t differentiate different signals from buttons for instance. This would allow more flexibility for future experiments I think.

I was just wondering if there are any e-prime code that can be used to identify the buttons. From what I can tell, the button detection can be set up under the “property pages” menu. I was just wondering if there was any set of code that can be also used for differentiating buttons?


I’ve never used E-Prime to be able to answer this question. But if you like, try uploading the code to the forums (may be even starting a new thread) and perhaps someone else who is an E-Prime guru can help.