intermittent logic

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That's for the oscilloscope, not the logic analyzer. And, that's for a phony glitch generated from a training board. In real life, it would be much more difficult to find a glitch in repetitive mode, just as the warning on the page tells you.

The glitch generated by the training board occurs more regularly than it would
in a malfunctioning system. Therefore, you will see the glitch on consecutive
traces.
Your twisting what it says, there is no warning, it explains why you see it on consecutive traces, it dosnt say warning this isnt a reliable way to do it
 

Brownout

Joined Jan 10, 2012
2,390
I read it correctly. Reproducing the manual in your post doesn't change anything.

The training board generates a simulated glitch. A real glitch might occur once a day or once a week. You have no chance of finding it running in repetitive mode. You need the correct tool, and that's not it.
 
I know from the many arguments you had with people over at ETO there is no point trying to argue with you. you interpret what it says to fit what you want.
The point is as they state, its more reliable to use the timing base of the LA to capture the Glitch, then they use that to trigger the scope so you see a dual screen, one of the LA timing trace and capture and imposed on that is the scope trace showing the actual glitch
 
I read it correctly. Reproducing the manual in your post doesn't change anything.

The training board generates a simulated glitch. A real glitch might occur once a day or once a week. You have no chance of finding it running in repetitive mode. You need the correct tool, and that's not it.

OK so what is the correct tool to find a glitch that happens once a week then?
I would still say the LA set up to trigger on a abnormal sequence in the timeing. what would you use for a once a week glitch?
 

Brownout

Joined Jan 10, 2012
2,390
I know from the many arguments you had with people over at ETO there is no point trying to argue with you.
What you should know about me is, I've been a professional for 20 years, and I know what I'm talking about. I see you're in love with your LA, but it's the wrong tool for this type of work. It's great for what it's made for, but there are tools that are much, much better for finding glitches.
 
What you should know about me is, I've been a professional for 20 years, and I know what I'm talking about. I see you're in love with your LA, but it's the wrong tool for this type of work. It's great for what it's made for, but there are tools that are much, much better for finding glitches.

OK what tool would you use for a once a week glitch? and by the way I didnt say run it in rep mode infact I posted this first

in the Repetitive Mode" exercise that the oscilloscope will not reliably trigger
on the glitch.

So again using your set up of a glitch once a week what is the better tool? after 20 years in the job what would you use?
And explain why HP train people to use this tool to find glitches if they are wrong?

 
one of the cards in my LA samples at 500MHz how is that too slow for some 30 year old 74 based chips?
and I am still waiting for you to explain about this better tool
 

Brownout

Joined Jan 10, 2012
2,390
HP people probably don't use this tool to find glitches. They have an exercise whereby a customer "finds" a simulated, aka not a real glitch by following directions and using a board that make a nice glitch that occurs often enough to find it with the wrong tool.

My recommendations are a high speed scope with statistical false coloring, as I wrote earlier.
 
HP people probably don't use this tool to find glitches. They have an exercise whereby a customer "finds" a simulated, aka not a real glitch by following directions and using a board that make a nice glitch that occurs often enough to find it with the wrong tool.

My recommendations are a high speed scope with statistical false coloring, as I wrote earlier.

LOL so they built a machine that when it was new cost more than a house, and they added all these complex and glitch triggering features to it just for a laugh?
The board and kit they produced was made to demonstrate some of the more complex features, its actually had alot of thought put into it.

Anyway explain to me how you would set up your scope to find this once a week glitch?

The advantage the LA has is the numbers of pins it can monitor before triggering, unless you know which chip has the glitch then your scope is no good at all on a once weekly glitch.
And why do you need such high speed on those chips? surely 100MHz is ample for them?
You should take a look at some of the older HP LA's some time, they were designed for this kind of thing. I am surprised you didnt know that.
:rolleyes: do you work with dexter by any chance?
 

atferrari

Joined Jan 6, 2004
4,764
Logic, 30 years ago, was also running fast and enjoyed the same nasty glitches as of today.

I understand the point here is the randomness of those glitches not what logic is producing them.
 

shortbus

Joined Sep 30, 2009
10,045
@LG and Brownout, you guys are starting to fall into the same trap that Dexter/Billy set over at ETO!!!!!! Don't do it!!!! Or if you must do it, please go to PM's to do it. He's sitting somewhere in the world (he won't say where), laughing his a$$ off over you guys about now. :(
 

Brownout

Joined Jan 10, 2012
2,390
LOL so they built a machine that when it was new cost more than a house, and they added all these complex and glitch triggering features to it just for a laugh?
Probably not for laughs, but glitch triggering has little practical use. Take, for example, glitching caused by cross-talk, a major reason for glitching. a 7cm victim trace would experience a 233fS glitch. The LA wouldn't stand a chance of catching it. That's why the test board generates a 10uS "glitch", which doesn't represent much found in the real world.

However, complex triggering is very practical. Just not for glitch tracing.
 

Thread Starter

DexterMccoy

Joined Feb 19, 2014
429
I found the IC chip that was causing the Glitching or false triggering when shutting the power off and turning the power on

It was a CD4017

What was causing this IC chip to do this? and what caused it to get this way?
 

Brownout

Joined Jan 10, 2012
2,390
Probably the external circuit, which we know nothing about.

Edit: glitches are to be expected on power up/down. That's why any sequential logic always includes a reset activity.
 
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Thread Starter

DexterMccoy

Joined Feb 19, 2014
429
It does have a Reset circuit to clear the Flip flops

But the CD4017 chip was outputting a glitch or false trigger logic state when the power was turned off or turned on

But any reason why Logic IC chips output a glitch like this when the power is turned off or on?
 

profbuxton

Joined Feb 21, 2014
421
well designed logic controls have a power on reset function which inhibits any signal changes taking place for a fixed period to allow logic states to stabilise on power on.
 
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