SUPPORT

 

 

Frequently Asked Questions (FAQ)

Contents:

• Where can I get datasheets for VPixx products?
• Do you have any demo code showing how to program the DATAPixx and VIEWPixx?
• How do I generate audio stimuli which are synchronized to video?
• How can I measure response times accurately?
• How can I synchronize electrophysiology data acquisition to video?
• How can I make a haploscope with synchronized displays?
• What is the pinout of the db-25 on the RESPONSEPixx button box?
• Can VPixx Technologies do custom development for my lab?
• How do I update the firmware revision of my VIEWPixx or DATAPixx?
• How do I reference VPixx Technologies in a publication or on my website?

• Where can I get datasheets for VPixx products?

All of our datasheets can be accessed from our downloads page.

• Do you have any demo code showing how to program the DATAPixx and VIEWPixx?

The DATAPixx and VIEWPixx can be easily programmed using the PsychToolbox, or a low-level ANSI C API. Demo source code can be found here. We support Windows XP, Windows 7, Mac OS X, and multiple flavors of Linux. The homepage for the PsychToolbox is at http://psychtoolbox.org/wikka.php?wakka=HomePage. Download, installation, and update instructions for the PTB is at http://psychtoolbox.org/wikka.php?wakka=PsychtoolboxDownload. Once the PTB has been installed, there are several paths to getting information on using the DATAPixx within the PTB. From Mario Kleiner: "All special graphics display functions (stereo, multi-display, mirroring, high precision color and luminance display) are supported via PsychImaging; e.g., demonstrated in BitsPlusCSFDemo, AdditiveBlendingForLinearSuperpositionTutorial and ImagingStereoDemo. Timestamping functionality and other convenience functions, as well as audio capture and voice keys are available via PsychDataPixx and DatapixxAudioKey, PsychPortAudioDatapixxTimingTest. See help DatapixxToolbox. All low-level features are supported via the Datapixx mex file driver". In addition, the DatapixxDemos folder contains a collection of low-level DATAPixx functional starting points for all of the basic functionality. DatapixxToolbox questions may be emailed to support@vpixx.com , or may be posted to the PTB forum if the questions are of a general nature whose answers may be useful to other DATAPixx users.

• How do I generate audio stimuli which are synchronized to video?

Multiple audio waveforms can be downloaded to the DATAPixx or VIEWPixx before an experiment or a trial begins. Your software then sends a request to begin playback of a specific audio waveform at some specific number of microseconds after the rising edge of the next video vertical sync pulse. Your program is then free to do other work while the DATAPixx hardware takes care of audio onset and playback timing with microsecond precision.

• How can I measure response times accurately?

The RESPONSEPixx is a straight TTL button box with no latency due to USB or serial interfaces. It plugs directly into the DATAPixx or VIEWPixx visual stimulators. The stimulator can precisely timetag the rising edge of the video vertical sync pulse for your stimulus onset. The stimulator can also precisely timetag the RESPONSEPixx button transitions. The difference between these two values is your subject response time with microsecond precision.

• How can I synchronize electrophysiology data acquisition to video?

The DATAPixx and VIEWPixx visual stimulators have 24 TTL digital outputs. These outputs can be used in combination as electrophysiology event markers, condition codes, and sampling triggers. As sample triggers, they can be programmed to generate a pulse train whose onset and frequency are synchronized to video with microsecond precision. Once the trigger sequence has been programmed, your software is free to move on to other tasks while the DATAPixx hardware takes care of the trigger generation. The DATAPixx itself also has 16 channels of 16-bit analog input which can be simultaneously sampled at up to 200,000 samples per second, also synchronized to video.

• How can I make a haploscope with synchronized displays?

The DATAPixx has dual VGA outputs which can drive dual synchronized CRTs from a single OpenGL context. The left half of your frame buffer is routed to one CRT, and the right half is routed to the other CRT. This way your software only needs to do a single OpenGL buffer swap, and the two displays update simultaneously. Our new VIEWPixx display works similarly. Two displays can be daisy chained off of a single video source. Each display shows a different part of a single OpenGL frame buffer, ensuring that the two displays update in perfect synchrony.

• What is the pinout of the db-25 on the RESPONSEPixx button box?

• Can VPixx Technologies do custom development for my lab?

VPixx Technologies has a long history of developing custom hardware and software for research labs. Our wide range of expertise includes:

• Digital and analog electrical engineering
• Mechanical design
• Software development
• Optics
• Electrophysiology
• Signal Processing
• Ergonomics

We can design new equipment from scratch, or we can often save you time and money by adapting one of our existing products to your requirements. The customization page describes some of our work.

• How do I update the firmware revision of my VIEWPixx or DATAPixx?

All VPixx Technologies programmable products are field upgradable, allowing your hardware functionality to evolve with your research. If you need to update the firmware, contact VPixx Technologies customer support and request the latest firmware revision. VPixx will email you the dpxutil command-line tool, along with the latest datapixx.bit or viewpixx.bit firmware file. Then just run the dpxutil reflash command from the DOS, Linux, or OS X command prompt. Here is an example for reflashing a DATAPixx under Mac OS X:

	MyName-MacBook-Pro:~ myname$ cd /Users/myname/Desktop/datapixx_fw 
	MyName-MacBook-Pro:datapixx_fw myname$ ./dpxutil -fpga_ufwpv datapixx.bit -q
	Flash Erase  100% completed
	Flash Write  100% completed
	Flash Verify 100% completed

Then turn your DATAPixx off and on to ensure that the new firmware is active, and your hardware has the new features!

• How do I reference VPixx Technologies in a publication or on my website?

For a publication, use the following text: (VPixx Technologies Inc.;http://www.vpixx.com)

For a website, simply insert the html code snippet below into your website's html source:

    <a href="http://www.vpixx.com">
    <img src="http://www.vpixx.com/images/vpixxsitelogo.gif" alt="VPixx Home" border="0"></a>

then your web page will contain the VPixx reference button shown here: