Comments on: Parallel port logic analyzer

By: Martin Hinner

Martin Hinner — Sat, 21 Mar 2009 19:59:46 +0000

You might be interested in yet-another-slow-logic analyzer I have created today: http://martin.hinner.info/electronics/piclogix/

The difference between those linked in this article and comments is that mine is standalone, i.e. requires no PC.

By: penjuin

penjuin — Fri, 01 Feb 2008 09:46:43 +0000

Cheers, will build one this weekend. Should last me until I can scrounge the cash for a real one. By the way, anyone have an opinion of analyzers in terms of usb vs standalone?

By: PixelTricks

PixelTricks — Tue, 29 Jan 2008 17:37:54 +0000

This works really well.
I used it last year to view signals from an IR receiver to read the commands that a tv remote control sends out.

By: abend

abend — Tue, 29 Jan 2008 17:36:36 +0000

I used the Fabulous Logic Analyzer for Linux. It uses pretty much the same hardware. This software and hardware combination were in the kits I gave away at Chaos Communication Camp. The software and schematics are available here: http://tfla-01.berlios.de/

By: giskard

giskard — Tue, 29 Jan 2008 11:40:55 +0000

This could probably be improved with the addition of an external power source and some high speed opto-couplers,to protect the computer properly.

By: 8Way

8Way — Tue, 29 Jan 2008 10:21:54 +0000

ACK! wrong post. i meant it for the pic rgb color changer. Doh!

By: 8Way

8Way — Tue, 29 Jan 2008 10:20:58 +0000

comment i left on the diylife board:

Nice design. I wonder if you get subtle flickers when updating the PWM values. I've found in my designs on the 14bit pics, that I have to update the PWM when my " 1 byte cycle counter" wraps to zero rather than immediately. You are clocking at a higher clock rate (I use 4-8mhz internal clocks with up to 10 PWM channels), so your design may not be so sensitive.

Recently, i've given up on the PIC and it's goofy architecture and moved to the Cypress PSOC parts. They are really neat with dedicated digital and analog blocks. You can set up up to 16 PWM (actually I use pseudo random bit sequences, which have less flicker) outputs, and the C compiler is really reliable vs the buggy stuff i've experienced w/ the pic (though the PSOC compiler generates crap code). The PSOC has it's own shortcomings, such as a really inefficient CPU, but the digital and analog blocks more than make up for it b/c stuff is done in HW vs SW. PSOC is really fun, esp when u wrap your head around it's way of doing things.

By: nickjohnson

nickjohnson — Tue, 29 Jan 2008 09:58:01 +0000

I built one of these a few years ago, including linux software: http://uvasux.googlepages.com/simplelogicanalyser

By: Emperor

Emperor — Tue, 29 Jan 2008 09:56:10 +0000

build one of these for your printer:
the hex file works with the 88, 48 and 168 i think. and besides, its well documented

http://www-user.tu-chemnitz.de/~heha/bastelecke/Rund%20um%20den%20PC/USB2LPT/ul-15.htm.en

then you will have a spare lpt port.

By: atrain

atrain — Tue, 29 Jan 2008 08:53:01 +0000

In other words, this just connects stuff directly to your parallel port. Should be very easy to make a Linux driver for this. Too bad my printer is parallel… time to upgrade :D

I think it would be nice to add some kind of playback support. Since those pins on the parallel port are bidirectional, it should be simple enough. Time to pull out my soldering iron!