Word Generators? - Page 1
Forum section: electronics / testgear

author: dentaku
author_rank: Frequent Contributor
timestamp: December 21, 2014, 08:56:11 pm
content: strange question I've been wondering about lately...Question 1: Certain circuit simulation applications have a Word Generator that lets you set up binary counters etc.I was wondering, has there ever been real hardware that does this? Something that looks like a function generator but outputs sequences of binary data?I know any microcontroller can do this but that's not the point.Question 2: I see that Jaspreet Kaleka made "parallel port user control" that does stuff like that and outputs from the parallel porthttp://jaspreetscodezone.blogspot.ca/2008/03/parallel-port-user-control.htmlI'm wondering if there's anything like this that has even more options you people might have used in the past?

author: rdl
author_rank: Super Contributor
timestamp: December 21, 2014, 09:16:23 pm
content: I think what you're looking for is a pattern generator. Digilent's Analog Discovery has one.

author: edavid
author_rank: Super Contributor
timestamp: December 21, 2014, 09:24:17 pm
content: Are you thinking of something like an HP 8016A?

author: tggzzz
author_rank: Super Contributor
timestamp: December 21, 2014, 10:43:14 pm
content: Quote from: dentaku on December 21, 2014, 08:56:11 pmNot a strange question at all.Commercial-off-the-shelf products are available for generic problems and also for highly specialised application domains. If they aren't suitable, then you can always build your own.Frequently it is necessary for equipment to have BIST (i.e. built-in self-test) capabilities, which for a digital circuit will be a pattern generator.

author: dentaku
author_rank: Frequent Contributor
timestamp: December 21, 2014, 10:57:42 pm
content: Quote from: edavid on December 21, 2014, 09:24:17 pmWow, so they DO existThat was certainly a very specialised device back in the 80's and must have been quite complicated to program.http://www.decadecounter.com/vta/articleview.php?item=35Now I've got to get out an old laptop that runs XP and has a parallel port to see what I can get out of the Parallel Port User Control software.I just want to make some simple up/down counters and such (without using a microcontroller) to put through a DAC and a breadboarded R-2R simply for the educational value.

author: dentaku
author_rank: Frequent Contributor
timestamp: December 21, 2014, 11:00:03 pm
content: Quote from: tggzzz on December 21, 2014, 10:43:14 pmOK. that actually makes sense.

author: SeanB
author_rank: Super Contributor
timestamp: December 22, 2014, 05:57:03 am
content: Cheapest is to buy or build a bus pirate, which can act as a limited word generator.

author: bubba198
author_rank: Contributor
timestamp: May 27, 2019, 12:24:08 am
content: @edavid Yes this is it, I got one, I do have the basic manual which barely explains that in a 8x32 mode the strobe acts like a 9th bit which is supposed to be controlled separately yet I can't get it to load no matter how I approach the loading piece.Has anyone used the HP 8016A and specifically the strobe in parallel mode as a 9th channel? If yes how to you load a value into the strobe since there isn't a 9th push button (there are 8 push buttons for the regular channels)?Thanks!

author: edavid
author_rank: Super Contributor
timestamp: May 27, 2019, 12:42:06 am
content: Quote from: bubba198 on May 27, 2019, 12:24:08 amThe manual says this:QuoteIs that not working on your 8016A?

author: oPossum
author_rank: Super Contributor
timestamp: May 27, 2019, 01:24:45 am
content: HP 8170A and 8175A are a few others.I have the 8175A with the analog option. It can 'playback' captures from the 1631D logic analyzer. Cool stuff.

author: bubba198
author_rank: Contributor
timestamp: May 27, 2019, 03:27:33 am
content: Hi, I can load the strobe and it seems to load correctly since I can do fetch and confirm that what I've loaded is present but when I replay the word sequence there's nothing on the strobe BNC, the data channels output waveform just fine but the strobe BNC is stuck at H all the time. I wonder if I have a defective unit which is quite possible. I did try RZ and NRZ on the strobe BNC and the result is consistent with no waveform being output.I did want to confirm the strobe loading sequence nonetheless with someone who has worked the 8016A before. I figured that when loading strobe one can pick multiple word locations, same applies when fetching the strobe -- the location LEDs where strobe is loaded, and by "loaded" I presume the strobe bit is set to 1 for those locations, so those location do light up when I press fetch. Still the BNC doesn't output anything so I just wanted to make sure this is the correct loading sequence before suspecting that the whole strobe circuitry maybe dead