PC-based Logic Analyzers

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Sambuchi
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PC-based Logic Analyzers

Post by Sambuchi » Tue Jan 13, 2009 4:10 am

I'm in the market for a PC-based Logic Analyzer.

I am googling right now and getting lots of hits.

The interesting thing for me is that I dont need anything very fast. I would say in the rates of 9600.

I am using the tool for its sampling capabilities. So it needs to store at least 8 bytes of data for me.

I will also say that the data that I am reading is being bit banged 56 bits long... so NO I cant do something like reading my data to hyperterminal.

NEEDS TO BE CHEAP TOO!

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Chupa
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Post by Chupa » Tue Jan 13, 2009 7:26 am

anything out there seems like it would be overkill for what you need.

http://www.pctestinstruments.com/ is a favorite $400

i own a http://www.tech-tools.com/dv_main.htm but that was before I learned of the logicport $500

http://www.saleae.com/logic/ is a small one for $150 that seems decent. Never herd anything about it but sparkfun sells it so its probably be decent.

Bigglez
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Re: PC-based Logic Analyzers

Post by Bigglez » Tue Jan 13, 2009 2:45 pm

Sambuchi wrote: I'm in the market for a PC-based Logic Analyzer.
Are you collecting physical layer data (risetimes, jitter,
amplitudes)? Or, are you collecting decoded data words?
Sambuchi wrote:The interesting thing for me is that I dont need anything very fast. I would say in the rates of 9600. I am using the tool for its sampling capabilities. So it needs to store at least 8 bytes of data for me.
Why not sample your unknown with a homebrew
uC based reader? You could collect a lot of data
and examine it later usin tools on a PC (or even the
uC tools running on your PC).
Sambuchi wrote: I will also say that the data that I am reading is being bit banged 56 bits long... so NO I cant do something like reading my data to hyperterminal.NEEDS TO BE CHEAP TOO!
Why not? Are saying you need to read 56 consecutive
words (bytes)?

A uC solution of your own should leave you "change
from a twenty" (dollar bill).

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haklesup
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Post by haklesup » Tue Jan 13, 2009 3:15 pm

Can I assume you are analyzing parallel data? How wide? 8 bits ? How long/deep is the data. ( 1 byte wide by 56 bits deep) or (1 bit wide by 8 words of 56 bits long). Nothing more than 8 bits wide will be cheap.

I ask because serial protocol analyzer might be another class of test equipment to look at. If you can stream it to or from a serial port (either direction), there are a number of software only utilities for capturing that data for analysis. Try Googling "Serial Spy". There are also a bunch of Parallel port monitor software out there of various capability. (strangely I got more hits with the misspelling parallell)

look around, I seem to recall some low performance (8 bit wide) logic analyzer projects based on the parallel port.

Here's one, it only uses one 74HCT245 and shareware software, is that cheap enough?
http://www.xs4all.nl/~jwasys/old/diy2.html

Lots more if you google "Parallel port logic analyzer"

Are you acquiring data synchronously or asynchronously (with or without a clock)?

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philba
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Post by philba » Tue Jan 13, 2009 3:59 pm

I've been looking at this one - http://www.sparkfun.com/commerce/produc ... ts_id=8938

Also, microchip's PICKit2 can be used as a 3 channel LA. It's only $35. (and you get a PIC programmer to boot...)

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Chupa
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Post by Chupa » Tue Jan 13, 2009 9:16 pm

philba wrote:Also, microchip's PICKit2 can be used as a 3 channel LA. It's only $35. (and you get a PIC programmer to boot...)
has that always been a feature or is that something new?

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