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Parallel Port Logic Analyzer

Few months ago I had ordered a new PCI parallel port card. It turned out my computer did not have a parallel port and I wanted to try parallel port logic analyzer software described here:
http://www.codeproject.com/Articles/75279/17-Channel-Logic-Analyzer

After downloading the software, I had to recompile it using the new IO port define of 0xD800 since that's what the PCI card had it mapped to.

Started it up and it worked really nicely!

I did not have the card's probes hooked up to any kind of special signal but only to a stable 5V. Tested the acquisition rate and it looked promising 50KHz.

I had a simple centronics interface and it prevented me from doing anything more at this point until I get a better cable; a simple DB25 would let me jump the pins to a breadboard.

Around that time, I have also tried several other ideas attempting to use the parallel port as a data acquisition interface to analyze the TTL logic. None really worked. I mean - some of them kind of worked. At the end, I did not feel that I could do any serious logic debug by using such makeshift things.

So, finally, I purchased a USB connected logic analyzer device with 8 channel data acquisition, a clone of a Saleae device.

Saleae Logic analyzer clone, 8 channels
Saleae Logic analyzer clone, 8 channels

I got it from China. I figured, even if it did not work, it was cheap enough to justify the risk.

After 4 weeks it arrived and it worked perfectly. So I purchased another one - this time a 16-channel device. It was a bit more expensive, but it also worked right out of the box!

Saleae Logic analyzer clone, 16 channels
Saleae Logic analyzer clone, 16 channels

Both devices are compatible with the fine software made by Saleae Logic:

http://www.saleae.com/logic/

The software is very polished and easy to work with.

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