Reconn's World Project Log - Oscilloscope Capture Program

OscopeCapture: Reverse Engineering the USB Protocol?

nospam@example.com (Andrew) — Thu, 20 Mar 2008 17:05:15 -0700

Ideally I could use the USB port on my oscilloscope instead of the RS-232 port. Why? Because USB is much more commonplace, and it's probably faster.

What's the problem then? I don't know how to interface to the oscilloscope.

GDS-820C uses an FTDI serial->USB converter chip for USB connectivity. It should be as easy as installing the drivers, and connecting via USB.

The latest Virtual Com Port (VCP) drivers should be available for you here: http://www.ftdichip.com/Drivers/VCP.htm

Continue reading "OscopeCapture: Reverse Engineering the USB Protocol?"

OscopeCapture : Installing Environment

nospam@example.com (Andrew) — Tue, 18 Mar 2008 20:57:00 -0700

I decided to write this program using python, as I've heard many great things about python.

Here are the packages I'm using:
- pyserial http://pyserial.sourceforge.net/
- matplotlib http://matplotlib.sourceforge.net/
- enstaller http://code.enthought.com/enstaller/

I grabbed pserial from the project page.

Matplotlib is a little different, I opted to download a package from Enthought (the enstaller) which will give me a graphical front end to install some handy python modules.

I followed the "Quick Installation Instructions" @ http://code.enthought.com/enstaller/

Making sure to add the appropriate python directories to my environment path in windows:

After that, load up a command line window and type 'enstaller'

this should load the gui



C:\Users\andrew>echo %PATH%

C:\Windows\system32;C:\Windows;C:\Windows\System32\Wbem;c:\Python25;c:\Python25\scripts



C:\Users\andrew>

C:\Users\andrew>enstaller

enstaller - version 2.2.0b3 on Python 2.5



Reading http://code.enthought.com/enstaller/eggs/windows/xp...Starting the Enstaller GUI...

At this step I selected to install the following packages:
- matplotlib
- numpy
- scipy
- wxPython

Afterthought: it may be better to install these packages manually..

Oscilloscope Waveform Capture Program Intro

nospam@example.com (Andrew) — Tue, 18 Mar 2008 20:27:35 -0700

Open Source SCPI Capture, Oscilloscope Display Program!

Now.. What is the point of this project??

I have an Instek Digital Storage Oscilloscope (GDS-820C) which has a USB & RS-232 serial connection. It came with software to capture waveforms & other data over USB or RS-232 (communicating with the SCPI spec). The problem is: the software sucks. So I decided "Hey, there's an API for this oscilloscope... I could write a better capture program."

And that's exactly what I'm doing.

background
Ok, so what the hell is SCPI? SCPI is an organization&specification for electronics testing equipment. The goal is to make different pieces of testing equipment talk the same language to the outside world. Such as the engineer's computer that is trying to pull the data. If all testing equipment uses the same language to send/receive data, then you could have one program that talks to all of your pieces of equipment. Which is really convenient. There is more info at http://www.scpiconsortium.org/

Tools used:
- python
- open source python modules
- oscilloscope that supports the SCPI protocol