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Messages from 157550

Article: 157550
Subject: Re: Using FPGA to feed 80386
From: chrisabele <ccabele@yahoo.com>
Date: Mon, 15 Dec 2014 21:19:45 -0500
Links: << >>  << T >>  << A >>
On 12/15/2014 6:38 PM, Rick C. Hodgin wrote:
> A focus:
> http://biblehub.com/philippians/4-13.htm
> "I can do all things through Christ which strengtheneth me."
>
> And a thought to consider:
> http://biblehub.com/matthew/12-30.htm
> "He that is not with me [Jesus] is against me; and he that gathereth
> not with me scattereth abroad."
>
> Have you received the Lord as your personal savior?  If not, I advise
> you to learn of Him.  The gospel message (the good news) is that we
> need not perish eternally.  Jesus Christ has come to the Earth to make
> a way back for us to be restored to God eternally in Heaven.  It is
> through His Atonement of sin at the cross.  Because He had no sin, and
> because of His Love for us, He took on our sin at the cross and died
> with it.  The punishment that was due us was given to Him, so that we
> might be made spotless and blameless before God, allowing us to enter
> in to Heaven.  Without us receiving His free gift of salvation, our
> sin remains upon us, and we must pay the price of our iniquity.
>
> Jesus is the most important person you can ever come to know.  I advise
> each of you to seek Him from within, just you and God.  When the TV is
> off, when the music is silent, when there are no distractions, listen
> to that still, small voice on the inside.  God desires to know you, and
> to save you from the punishment due you from your sin.
>
> -----
> As for this forum...
>
> I appreciate everyone's advice.  I view a lot of that advice as overt
> negativity and down-putting rather than an effort toward helpful
> assistance.  As such, I will depart this group now and continue on
> in service to the Lord on my own.  In Him there is hope, guidance,
> life, and peace.  His is the better place to be as the people who seek
> Him look to build each other up, to help each other out, and not cut
> each other down.  This is the difference between people who pursue
> Jesus Christ, and people who pursue anything else.
>
> Our life has a purpose and a name:  Jesus Christ.
>
> Seek Him, to learn of Him, that He may set you free from the falseness
> of this world.  Peace.
>
> Best regards,
> Rick C. Hodgin
>

Wow, are people really like that?

I read this group regularly because I learn a lot from the frequent 
contributors who clearly have a great deal of practical experience. And 
I appreciate the fact that you're willing to share your knowledge with 
those of us who need some help. This guy has gotten a large amount of 
useful expert advice (for free!), and then tells the whole group that 
we're rude and not really worthy humans unless we agree with his beliefs.

I can't really comment on the falseness of the world, but I sincerely 
hope that he remains free of the falseness of this newsgroup for ever after.


Article: 157551
Subject: Re: Monitor connections
From: rickman <gnuarm@gmail.com>
Date: Mon, 15 Dec 2014 22:24:45 -0500
Links: << >>  << T >>  << A >>
On 12/12/2014 2:22 PM, Theo Markettos wrote:
> Rick C. Hodgin <rick.c.hodgin@gmail.com> wrote:
>> Is there a way to monitor signals in existing
>> wires? For example, with an oscilloscope and
>> probe I can watch voltage changes. Is there a
>> standard way to connect to an existing, working
>> device, and monitor and record its switching
>> over time? Such would seem to be desirable for
>> peeking at proprietary "wake up" chirps, and to
>> monitor device communications to establish its
>> protocol interface.
>
> Xilinx has ChipScope and Altera has SignalTap.  These are logic analysers
> that you can put inside the FPGA and attach to signals to monitor the state
> of your design.
>
> There are some caveats:
> Typically changing the probe state requires a recompile of your design
> (which can take hours)
> The amount of state you can record is limited by the internal memory in your
> device
>
> but it's still far better than trying to route signals outside and using a
> real logic analyser.

I've done the logic analyzer thing before.  A board I have in production 
has 9 signals it can drive on a 10 pin connector to see internal state. 
  To be most useful I used a mux to select which internal signals drive 
these outputs.  There is an undocumented control register in the FPGA to 
control the mux.  But even with this if I need a signal that I hadn't 
planned for, I have to reprogram the FPGA.

To Rick C.'s question, I have never seen a probe intended to save you 
the trouble of accessing one end of the wire.  A needle can be used to 
pierce the insulation if needed.

-- 

Rick

Article: 157552
Subject: Re: VHDL Synchronization- two stage FF on all inputs?
From: rickman <gnuarm@gmail.com>
Date: Mon, 15 Dec 2014 22:47:28 -0500
Links: << >>  << T >>  << A >>
On 12/15/2014 6:14 PM, GaborSzakacs wrote:
> rickman wrote:
>> On 12/12/2014 5:05 PM, GaborSzakacs wrote:
>>> rickman wrote:
>>>> On 12/12/2014 2:45 PM, GaborSzakacs wrote:
>>>>> rickman wrote:
>>>>>> On 12/11/2014 9:08 AM, GaborSzakacs wrote:
>>>>>
>>>>> [snip]
>>>
>>>>>
>>>>> No.  The second flip-flop has the same sort of metastable window as
>>>>> the
>>>>> first.  If the first flop misses that window because the metastability
>>>>> was longer, then the second flop will resolve on the following clock
>>>>> cycle.  I think you may be under the misapprehension that the
>>>>> metastable
>>>>> state means that the first flop is outputing a "1/2" rather that "0"
>>>>> or "1" logic level and any sampling during that time would cause
>>>>> metastability in the second flop.  In fact that's not the case.
>>>>
>>>> I don't think that is correct.  A metastable event can create all
>>>> sorts of problems on the output including oscillations and
>>>> indeterminate levels.  These can produce metastability in the second
>>>> stage without having to hit a bullet with a bullet.
>>>>
>>>>
>>>
>>> Think again.  A flip-flop has positive feedback gain.  Oscillation
>>> is definitely not a possibility.  Somewhere inside the flop you
>>> could sit at a threshold voltage for a while, but once you start
>>> to resolve, the swing will be monotonic.  The next flop doesn't
>>> get fed directly by the node sitting at its threshold, but from
>>> a buffered copy.  You'd need a buffer that oscillates when its
>>> input sits near a threshold for a nanosecond or two.  You won't
>>> find anything like that in an FPGA.
>>
>> There is some 40 years of experience and documentation showing the
>> effects of metastability.  Please do a little research on the topic.
>>
> Rick,
>
>    If you had even started to look into some of that 40 years of
> research, you may have come across a host of articles like this one:
>
> http://webee.technion.ac.il/~ran/papers/Metastability-and-Synchronizers.IEEEDToct2011.pdf
>
>
> The only mention of oscillation is that it doesn't happen.  At least
> not at the output latch node.

This one says it can oscillate...
http://www.ganssle.com/articles/MetastabilityandFirmware.htm

This one does too...
http://a.vita.com/home/Learn/vmefaq/metastability.html

Another...
http://www-classes.usc.edu/engr/ee-s/552/coursematerials/ee552-G1.pdf

This one has pictures...
http://www.asic-world.com/tidbits/metastablity.html

You can talk about positive feedback, but that does not preclude 
oscillations.  With the appropriate condition such as the data input 
changing at the right time just around the clock edge, both outputs of 
the master FF (Q and Q not) can be in the same state.  With 
approximately equal delays in each gate, this condition will change to 
both outputs changing to the opposite state, then back, etc until one of 
the states "catches up" with the other and the circuit reaches a stable 
state.

Some of the very earliest work analyzing the metastable state in digital 
logic well documented oscillations in such circuits.  Anyone who tells 
you otherwise is talking through their hats.

-- 

Rick

Article: 157553
Subject: Re: Using FPGA to feed 80386
From: rickman <gnuarm@gmail.com>
Date: Mon, 15 Dec 2014 22:59:06 -0500
Links: << >>  << T >>  << A >>
On 12/15/2014 7:05 PM, Tim Wescott wrote:
> On Sun, 14 Dec 2014 10:47:45 -0800, Rick C. Hodgin wrote:
>
>> How would I go about making my own boards?
>> I am aware of commercial companies which have software you can download,
>> and construct the layout through their process manufacturing,
>> and you will receive boards and solder masks.
>>
>> But are there things you can do yourself? Buy a blank copper layer,
>> cover with a photoresist, expose a mask, and then chemically etch away
>> the exposed or unexposed are (depending on the resist)?
>
> There is a middle road.
>
> Get a copy of Eagle or KiCad, lay the board out, and get Gerber files.
> Gerber files are universal, unlike the captive software that you're
> talking about.

Unless you use a fab house that uses crap software like ITEAD.  The use 
software the mucks up the images for Gerber files which use certain 
constructs.  They will remake the boards correctly, but it's a PITA. 
They are cheap though.


> Then send the Gerber files to a board aggregator (i.e., www.oshpark.com).
> Oshpark charges $5.00 per square inch and sends you three boards, which is
> not a bad price at all.  You'll only get a 2-layer board, which may not be
> enough.  They also do 4-layer, for more money and slower service.
>
> You're definitely diving off the deep end without a life preserver, here
> -- would your experience be more complete if someone tied you up in a bag
> before you jumped into the water?

He's not diving off anything.  He is just testing the waters by sticking 
his toe in and asking us how it feels.

-- 

Rick

Article: 157554
Subject: Re: Using FPGA to feed 80386
From: rickman <gnuarm@gmail.com>
Date: Mon, 15 Dec 2014 23:05:21 -0500
Links: << >>  << T >>  << A >>
On 12/14/2014 9:33 PM, hamilton wrote:
> On 12/14/2014 6:11 PM, Rick C. Hodgin wrote:
>> Version 2.0. Much faster, cleaner:
>>
>>     http://m.youtube.com/watch?v=uIIwU29H3E8
>>
>> Best regards,
>> Rick C. Hodgin
>>
>
> LOL, did you notice that the PCB is white and not green ??
>
> What to know why ??

I guess I do.  I wouldn't have expected it to be green.  Given that it 
is be whacked by a laser, I'm not sure I would expect any color to show 
up.  Is this forming some oxide of copper that resists the acid?  Or has 
the board been sprayed with a photosensitive agent?

-- 

Rick

Article: 157555
Subject: Re: Using FPGA to feed 80386
From: rickman <gnuarm@gmail.com>
Date: Mon, 15 Dec 2014 23:06:26 -0500
Links: << >>  << T >>  << A >>
On 12/15/2014 6:38 PM, Rick C. Hodgin wrote:

...snip...

> -----
> As for this forum...
>
> I appreciate everyone's advice.  I view a lot of that advice as overt
> negativity and down-putting rather than an effort toward helpful
> assistance.  As such, I will depart this group now and continue on
> in service to the Lord on my own.

I think this says a lot more than any of the religious stuff.  If he 
isn't "understood" we are being negative.  The reality is that he has a 
*lot* to learn and is asking questions.  I don't have a problem with 
that.  But when he doesn't like the answers he gets he retreats into his 
cave of god and lets us know it is our problem not his.  That's just 
being immature.

-- 

Rick

Article: 157556
Subject: Re: Using FPGA to feed 80386
From: rickman <gnuarm@gmail.com>
Date: Mon, 15 Dec 2014 23:06:53 -0500
Links: << >>  << T >>  << A >>
On 12/15/2014 9:19 PM, chrisabele wrote:
> On 12/15/2014 6:38 PM, Rick C. Hodgin wrote:
>> A focus:
>> http://biblehub.com/philippians/4-13.htm
>> "I can do all things through Christ which strengtheneth me."
>>
>> And a thought to consider:
>> http://biblehub.com/matthew/12-30.htm
>> "He that is not with me [Jesus] is against me; and he that gathereth
>> not with me scattereth abroad."
>>
>> Have you received the Lord as your personal savior?  If not, I advise
>> you to learn of Him.  The gospel message (the good news) is that we
>> need not perish eternally.  Jesus Christ has come to the Earth to make
>> a way back for us to be restored to God eternally in Heaven.  It is
>> through His Atonement of sin at the cross.  Because He had no sin, and
>> because of His Love for us, He took on our sin at the cross and died
>> with it.  The punishment that was due us was given to Him, so that we
>> might be made spotless and blameless before God, allowing us to enter
>> in to Heaven.  Without us receiving His free gift of salvation, our
>> sin remains upon us, and we must pay the price of our iniquity.
>>
>> Jesus is the most important person you can ever come to know.  I advise
>> each of you to seek Him from within, just you and God.  When the TV is
>> off, when the music is silent, when there are no distractions, listen
>> to that still, small voice on the inside.  God desires to know you, and
>> to save you from the punishment due you from your sin.
>>
>> -----
>> As for this forum...
>>
>> I appreciate everyone's advice.  I view a lot of that advice as overt
>> negativity and down-putting rather than an effort toward helpful
>> assistance.  As such, I will depart this group now and continue on
>> in service to the Lord on my own.  In Him there is hope, guidance,
>> life, and peace.  His is the better place to be as the people who seek
>> Him look to build each other up, to help each other out, and not cut
>> each other down.  This is the difference between people who pursue
>> Jesus Christ, and people who pursue anything else.
>>
>> Our life has a purpose and a name:  Jesus Christ.
>>
>> Seek Him, to learn of Him, that He may set you free from the falseness
>> of this world.  Peace.
>>
>> Best regards,
>> Rick C. Hodgin
>>
>
> Wow, are people really like that?
>
> I read this group regularly because I learn a lot from the frequent
> contributors who clearly have a great deal of practical experience. And
> I appreciate the fact that you're willing to share your knowledge with
> those of us who need some help. This guy has gotten a large amount of
> useful expert advice (for free!), and then tells the whole group that
> we're rude and not really worthy humans unless we agree with his beliefs.
>
> I can't really comment on the falseness of the world, but I sincerely
> hope that he remains free of the falseness of this newsgroup for ever
> after.

I think he'll be back.

-- 

Rick

Article: 157557
Subject: Re: Using FPGA to feed 80386
From: Tom Gardner <spamjunk@blueyonder.co.uk>
Date: Tue, 16 Dec 2014 11:52:19 +0000
Links: << >>  << T >>  << A >>
On 16/12/14 02:19, chrisabele wrote:
> On 12/15/2014 6:38 PM, Rick C. Hodgin wrote:
>> A focus:
>> http://biblehub.com/philippians/4-13.htm
>> "I can do all things through Christ which strengtheneth me."
>>
>> And a thought to consider:
>> http://biblehub.com/matthew/12-30.htm
>> "He that is not with me [Jesus] is against me; and he that gathereth
>> not with me scattereth abroad."
>>
>> Have you received the Lord as your personal savior?  If not, I advise
>> you to learn of Him.  The gospel message (the good news) is that we
>> need not perish eternally.  Jesus Christ has come to the Earth to make
>> a way back for us to be restored to God eternally in Heaven.  It is
>> through His Atonement of sin at the cross.  Because He had no sin, and
>> because of His Love for us, He took on our sin at the cross and died
>> with it.  The punishment that was due us was given to Him, so that we
>> might be made spotless and blameless before God, allowing us to enter
>> in to Heaven.  Without us receiving His free gift of salvation, our
>> sin remains upon us, and we must pay the price of our iniquity.
>>
>> Jesus is the most important person you can ever come to know.  I advise
>> each of you to seek Him from within, just you and God.  When the TV is
>> off, when the music is silent, when there are no distractions, listen
>> to that still, small voice on the inside.  God desires to know you, and
>> to save you from the punishment due you from your sin.
>>
>> -----
>> As for this forum...
>>
>> I appreciate everyone's advice.  I view a lot of that advice as overt
>> negativity and down-putting rather than an effort toward helpful
>> assistance.  As such, I will depart this group now and continue on
>> in service to the Lord on my own.  In Him there is hope, guidance,
>> life, and peace.  His is the better place to be as the people who seek
>> Him look to build each other up, to help each other out, and not cut
>> each other down.  This is the difference between people who pursue
>> Jesus Christ, and people who pursue anything else.
>>
>> Our life has a purpose and a name:  Jesus Christ.
>>
>> Seek Him, to learn of Him, that He may set you free from the falseness
>> of this world.  Peace.
>>
>> Best regards,
>> Rick C. Hodgin
>>
>
> Wow, are people really like that?
>
> I read this group regularly because I learn a lot from the frequent contributors
> who clearly have a great deal of practical experience. And I appreciate the fact
> that you're willing to share your knowledge with those of us who need some help.
> This guy has gotten a large amount of useful expert advice (for free!), and then
> tells the whole group that we're rude and not really worthy humans unless we
> agree with his beliefs.

See Hodgin's posts in comp.arch; the followed a similar pattern
and conclusions.

The major difference was that he did a *lot* more proselyting
(and wouldn't stop). Sadly this appears to have been the consequence
of some unspecified Bad Events in his life.

I hope we have enabled him to concentrate his efforts on something
that stands a chance of being successful.


Article: 157558
Subject: Re: Using FPGA to feed 80386
From: Tom Gardner <spamjunk@blueyonder.co.uk>
Date: Tue, 16 Dec 2014 11:54:26 +0000
Links: << >>  << T >>  << A >>
On 16/12/14 04:06, rickman wrote:
> On 12/15/2014 6:38 PM, Rick C. Hodgin wrote:
>
> ...snip...
>
>> -----
>> As for this forum...
>>
>> I appreciate everyone's advice.  I view a lot of that advice as overt
>> negativity and down-putting rather than an effort toward helpful
>> assistance.  As such, I will depart this group now and continue on
>> in service to the Lord on my own.
>
> I think this says a lot more than any of the religious stuff.  If he isn't
> "understood" we are being negative.  The reality is that he has a *lot* to learn
> and is asking questions.  I don't have a problem with that.  But when he doesn't
> like the answers he gets he retreats into his cave of god and lets us know it is
> our problem not his.  That's just being immature.

The only part of that I disagree with is "being immature". based on
his comp.arch posts, I suspect it is more complex than that.


Article: 157559
Subject: Re: Monitor connections
From: Tom Gardner <spamjunk@blueyonder.co.uk>
Date: Tue, 16 Dec 2014 11:56:21 +0000
Links: << >>  << T >>  << A >>
On 16/12/14 03:24, rickman wrote:

> To Rick C.'s question, I have never seen a probe intended to save you the
> trouble of accessing one end of the wire.

A current probe can do that, with significant limitations, of course!


Article: 157560
Subject: Re: VHDL Synchronization- two stage FF on all inputs?
From: Tom Gardner <spamjunk@blueyonder.co.uk>
Date: Tue, 16 Dec 2014 11:58:23 +0000
Links: << >>  << T >>  << A >>
On 15/12/14 23:14, GaborSzakacs wrote:
> The only mention of oscillation is that it doesn't happen.  At least
> not at the output latch node.

Oscillation vs invalid level is dependent on the logic family.
I would go and dig out some 30/40 year old oscillograms, but
they are currently inaccessible.

Article: 157561
Subject: Re: VHDL Synchronization- two stage FF on all inputs?
From: GaborSzakacs <gabor@alacron.com>
Date: Tue, 16 Dec 2014 11:58:40 -0500
Links: << >>  << T >>  << A >>
rickman wrote:
> On 12/15/2014 6:14 PM, GaborSzakacs wrote:
>> rickman wrote:
>>> On 12/12/2014 5:05 PM, GaborSzakacs wrote:
>>>> rickman wrote:
>>>>> On 12/12/2014 2:45 PM, GaborSzakacs wrote:
>>>>>> rickman wrote:
>>>>>>> On 12/11/2014 9:08 AM, GaborSzakacs wrote:
>>>>>>
>>>>>> [snip]
>>>>
>>>>>>
>>>>>> No.  The second flip-flop has the same sort of metastable window as
>>>>>> the
>>>>>> first.  If the first flop misses that window because the 
>>>>>> metastability
>>>>>> was longer, then the second flop will resolve on the following clock
>>>>>> cycle.  I think you may be under the misapprehension that the
>>>>>> metastable
>>>>>> state means that the first flop is outputing a "1/2" rather that "0"
>>>>>> or "1" logic level and any sampling during that time would cause
>>>>>> metastability in the second flop.  In fact that's not the case.
>>>>>
>>>>> I don't think that is correct.  A metastable event can create all
>>>>> sorts of problems on the output including oscillations and
>>>>> indeterminate levels.  These can produce metastability in the second
>>>>> stage without having to hit a bullet with a bullet.
>>>>>
>>>>>
>>>>
>>>> Think again.  A flip-flop has positive feedback gain.  Oscillation
>>>> is definitely not a possibility.  Somewhere inside the flop you
>>>> could sit at a threshold voltage for a while, but once you start
>>>> to resolve, the swing will be monotonic.  The next flop doesn't
>>>> get fed directly by the node sitting at its threshold, but from
>>>> a buffered copy.  You'd need a buffer that oscillates when its
>>>> input sits near a threshold for a nanosecond or two.  You won't
>>>> find anything like that in an FPGA.
>>>
>>> There is some 40 years of experience and documentation showing the
>>> effects of metastability.  Please do a little research on the topic.
>>>
>> Rick,
>>
>>    If you had even started to look into some of that 40 years of
>> research, you may have come across a host of articles like this one:
>>
>> http://webee.technion.ac.il/~ran/papers/Metastability-and-Synchronizers.IEEEDToct2011.pdf 
>>
>>
>>
>> The only mention of oscillation is that it doesn't happen.  At least
>> not at the output latch node.
> 
> This one says it can oscillate...
> http://www.ganssle.com/articles/MetastabilityandFirmware.htm
> 
> This one does too...
> http://a.vita.com/home/Learn/vmefaq/metastability.html
> 
> Another...
> http://www-classes.usc.edu/engr/ee-s/552/coursematerials/ee552-G1.pdf
> 
> This one has pictures...
> http://www.asic-world.com/tidbits/metastablity.html
> 
> You can talk about positive feedback, but that does not preclude 
> oscillations.  With the appropriate condition such as the data input 
> changing at the right time just around the clock edge, both outputs of 
> the master FF (Q and Q not) can be in the same state.  With 
> approximately equal delays in each gate, this condition will change to 
> both outputs changing to the opposite state, then back, etc until one of 
> the states "catches up" with the other and the circuit reaches a stable 
> state.
> 
> Some of the very earliest work analyzing the metastable state in digital 
> logic well documented oscillations in such circuits.  Anyone who tells 
> you otherwise is talking through their hats.
> 

Any older ones?  CMOS flip-flops built from transfer gates will not
oscillate.  The only reputable instances I could find showing
oscillation referred to much older families that used cross-coupled
gates.  Note that there are no "Q and Q not" outputs of a CMOS
flip-flop unless "Q not" is generated with an inversion after the
transfer gate latch.  Cross-coupled gate implementations could
oscillate.  You won't find those in an FPGA.

Article: 157562
Subject: Re: VHDL Synchronization- two stage FF on all inputs?
From: "mnentwig" <24789@embeddedrelated>
Date: Tue, 16 Dec 2014 11:31:25 -0600
Links: << >>  << T >>  << A >>
A simple thought on the topic, as it's often difficult to see the forest
for the trees:

When an asynchronous signal is sampled, there can be timing violations. No
number of chained FFs can give a _deterministic_ result. But they guarantee
that it won't change between clock cycles and will look the same to all
connected inputs, whatever the value. 

For example, a metastable reset could release some blocks one cycle before
others, and the circuit is off to a bad start.	   
					
---------------------------------------		
Posted through http://www.FPGARelated.com

Article: 157563
Subject: Re: Using FPGA to feed 80386
From: hamilton <hamilton@nothere.com>
Date: Tue, 16 Dec 2014 11:07:23 -0700
Links: << >>  << T >>  << A >>
>> On 12/15/2014 6:38 PM, Rick C. Hodgin wrote:  <SNIP>

WOW, another right wing nut case !!

Hey Rick, when you go off the deep end will you find a chocolate shop to 
visit ??

http://www.godchecker.com/


Article: 157564
Subject: Re: Monitor connections
From: GaborSzakacs <gabor@alacron.com>
Date: Tue, 16 Dec 2014 14:09:19 -0500
Links: << >>  << T >>  << A >>
Tom Gardner wrote:
> On 16/12/14 03:24, rickman wrote:
> 
>> To Rick C.'s question, I have never seen a probe intended to save you the
>> trouble of accessing one end of the wire.
> 
> A current probe can do that, with significant limitations, of course!
> 

or a needle stuck in the middle of the wire (assuming we're
talking discrete wires and not a trace inside an IC).  There
are also insulation displacement quick-connects made for
tapping into automotive wiring.  On the other hand I've heard
the OP has moved on, so we'll probably never really know what
the intent of the question really was.

Article: 157565
Subject: Re: Monitor connections
From: Arne Pagel <arne@pagelnet.de>
Date: Tue, 16 Dec 2014 21:52:43 +0100
Links: << >>  << T >>  << A >>
Not sure what you are really looking for,
there are some methods around trying to decrypt the bitstream:

https://www.cosic.esat.kuleuven.be/publications/article-737.pdf

http://perso.uclouvain.be/fstandae/PUBLIS/12.pdf



Article: 157566
Subject: Re: VHDL Synchronization- two stage FF on all inputs?
From: rickman <gnuarm@gmail.com>
Date: Tue, 16 Dec 2014 16:11:37 -0500
Links: << >>  << T >>  << A >>
On 12/16/2014 11:58 AM, GaborSzakacs wrote:
> rickman wrote:
>> On 12/15/2014 6:14 PM, GaborSzakacs wrote:
>>> rickman wrote:
>>>> On 12/12/2014 5:05 PM, GaborSzakacs wrote:
>>>>> rickman wrote:
>>>>>> On 12/12/2014 2:45 PM, GaborSzakacs wrote:
>>>>>>> rickman wrote:
>>>>>>>> On 12/11/2014 9:08 AM, GaborSzakacs wrote:
>>>>>>>
>>>>>>> [snip]
>>>>>
>>>>>>>
>>>>>>> No.  The second flip-flop has the same sort of metastable window as
>>>>>>> the
>>>>>>> first.  If the first flop misses that window because the
>>>>>>> metastability
>>>>>>> was longer, then the second flop will resolve on the following clock
>>>>>>> cycle.  I think you may be under the misapprehension that the
>>>>>>> metastable
>>>>>>> state means that the first flop is outputing a "1/2" rather that "0"
>>>>>>> or "1" logic level and any sampling during that time would cause
>>>>>>> metastability in the second flop.  In fact that's not the case.
>>>>>>
>>>>>> I don't think that is correct.  A metastable event can create all
>>>>>> sorts of problems on the output including oscillations and
>>>>>> indeterminate levels.  These can produce metastability in the second
>>>>>> stage without having to hit a bullet with a bullet.
>>>>>>
>>>>>>
>>>>>
>>>>> Think again.  A flip-flop has positive feedback gain.  Oscillation
>>>>> is definitely not a possibility.  Somewhere inside the flop you
>>>>> could sit at a threshold voltage for a while, but once you start
>>>>> to resolve, the swing will be monotonic.  The next flop doesn't
>>>>> get fed directly by the node sitting at its threshold, but from
>>>>> a buffered copy.  You'd need a buffer that oscillates when its
>>>>> input sits near a threshold for a nanosecond or two.  You won't
>>>>> find anything like that in an FPGA.
>>>>
>>>> There is some 40 years of experience and documentation showing the
>>>> effects of metastability.  Please do a little research on the topic.
>>>>
>>> Rick,
>>>
>>>    If you had even started to look into some of that 40 years of
>>> research, you may have come across a host of articles like this one:
>>>
>>> http://webee.technion.ac.il/~ran/papers/Metastability-and-Synchronizers.IEEEDToct2011.pdf
>>>
>>>
>>>
>>> The only mention of oscillation is that it doesn't happen.  At least
>>> not at the output latch node.
>>
>> This one says it can oscillate...
>> http://www.ganssle.com/articles/MetastabilityandFirmware.htm
>>
>> This one does too...
>> http://a.vita.com/home/Learn/vmefaq/metastability.html
>>
>> Another...
>> http://www-classes.usc.edu/engr/ee-s/552/coursematerials/ee552-G1.pdf
>>
>> This one has pictures...
>> http://www.asic-world.com/tidbits/metastablity.html
>>
>> You can talk about positive feedback, but that does not preclude
>> oscillations.  With the appropriate condition such as the data input
>> changing at the right time just around the clock edge, both outputs of
>> the master FF (Q and Q not) can be in the same state.  With
>> approximately equal delays in each gate, this condition will change to
>> both outputs changing to the opposite state, then back, etc until one
>> of the states "catches up" with the other and the circuit reaches a
>> stable state.
>>
>> Some of the very earliest work analyzing the metastable state in
>> digital logic well documented oscillations in such circuits.  Anyone
>> who tells you otherwise is talking through their hats.
>>
>
> Any older ones?  CMOS flip-flops built from transfer gates will not
> oscillate.  The only reputable instances I could find showing
> oscillation referred to much older families that used cross-coupled
> gates.  Note that there are no "Q and Q not" outputs of a CMOS
> flip-flop unless "Q not" is generated with an inversion after the
> transfer gate latch.  Cross-coupled gate implementations could
> oscillate.  You won't find those in an FPGA.

If you are talking about the circuit shown in your reference it will 
still oscillate the same way as a gate based FF.  Each inverter in the 
loop produces a signal, one is Q the other is Q not whether it is 
labeled as such or not.  Oscillations happen.

-- 

Rick

Article: 157567
Subject: Re: Using FPGA to feed 80386
From: rickman <gnuarm@gmail.com>
Date: Tue, 16 Dec 2014 16:34:01 -0500
Links: << >>  << T >>  << A >>
On 12/16/2014 1:07 PM, hamilton wrote:
>>> On 12/15/2014 6:38 PM, Rick C. Hodgin wrote:  <SNIP>
>
> WOW, another right wing nut case !!
>
> Hey Rick, when you go off the deep end will you find a chocolate shop to
> visit ??

Right wing?  His comments were religious.  The right wing label is 
political.  What is the connection here?

-- 

Rick

Article: 157568
Subject: Re: Using FPGA to feed 80386
From: rickman <gnuarm@gmail.com>
Date: Tue, 16 Dec 2014 16:35:58 -0500
Links: << >>  << T >>  << A >>
On 12/16/2014 6:54 AM, Tom Gardner wrote:
> On 16/12/14 04:06, rickman wrote:
>> On 12/15/2014 6:38 PM, Rick C. Hodgin wrote:
>>
>> ...snip...
>>
>>> -----
>>> As for this forum...
>>>
>>> I appreciate everyone's advice.  I view a lot of that advice as overt
>>> negativity and down-putting rather than an effort toward helpful
>>> assistance.  As such, I will depart this group now and continue on
>>> in service to the Lord on my own.
>>
>> I think this says a lot more than any of the religious stuff.  If he
>> isn't
>> "understood" we are being negative.  The reality is that he has a
>> *lot* to learn
>> and is asking questions.  I don't have a problem with that.  But when
>> he doesn't
>> like the answers he gets he retreats into his cave of god and lets us
>> know it is
>> our problem not his.  That's just being immature.
>
> The only part of that I disagree with is "being immature". based on
> his comp.arch posts, I suspect it is more complex than that.

Ok.  I won't argue.  I don't mind his questions as well as his misplaced 
enthusiasm.  I also think some of the comments here were a little hard 
on him.  If he really wants to learn some things I'm happy to help.

-- 

Rick

Article: 157569
Subject: Re: Monitor connections
From: rickman <gnuarm@gmail.com>
Date: Tue, 16 Dec 2014 16:37:07 -0500
Links: << >>  << T >>  << A >>
On 12/16/2014 6:56 AM, Tom Gardner wrote:
> On 16/12/14 03:24, rickman wrote:
>
>> To Rick C.'s question, I have never seen a probe intended to save you the
>> trouble of accessing one end of the wire.
>
> A current probe can do that, with significant limitations, of course!

A current probe measures current, not voltage.  It is a pretty poor way 
to measure signals.

-- 

Rick

Article: 157570
Subject: Re: Using FPGA to feed 80386
From: hamilton <hamilton@nothere.com>
Date: Tue, 16 Dec 2014 15:15:30 -0700
Links: << >>  << T >>  << A >>
On 12/16/2014 2:34 PM, rickman wrote:
> On 12/16/2014 1:07 PM, hamilton wrote:
>>>> On 12/15/2014 6:38 PM, Rick C. Hodgin wrote:  <SNIP>
>>
>> WOW, another right wing nut case !!
>>
>> Hey Rick, when you go off the deep end will you find a chocolate shop to
>> visit ??
>
> Right wing?  His comments were religious.  The right wing label is
> political.  What is the connection here?
>

http://bit.ly/1DIDd29

Article: 157571
Subject: Re: Using FPGA to feed 80386
From: hamilton <hamilton@nothere.com>
Date: Tue, 16 Dec 2014 15:34:08 -0700
Links: << >>  << T >>  << A >>
On 12/16/2014 2:34 PM, rickman wrote:
> On 12/16/2014 1:07 PM, hamilton wrote:
>>>> On 12/15/2014 6:38 PM, Rick C. Hodgin wrote:  <SNIP>
>>
>> WOW, another right wing nut case !!
>>
>> Hey Rick, when you go off the deep end will you find a chocolate shop to
>> visit ??
>
> Right wing?  His comments were religious.  The right wing label is
> political.  What is the connection here?
>
http://www.salon.com/2014/02/22/reagans_christian_revolt_how_conservatives_hijacked_american_religion/


Article: 157572
Subject: Re: Using FPGA to feed 80386
From: rickman <gnuarm@gmail.com>
Date: Tue, 16 Dec 2014 22:58:03 -0500
Links: << >>  << T >>  << A >>
On 12/16/2014 5:34 PM, hamilton wrote:
> On 12/16/2014 2:34 PM, rickman wrote:
>> On 12/16/2014 1:07 PM, hamilton wrote:
>>>>> On 12/15/2014 6:38 PM, Rick C. Hodgin wrote:  <SNIP>
>>>
>>> WOW, another right wing nut case !!
>>>
>>> Hey Rick, when you go off the deep end will you find a chocolate shop to
>>> visit ??
>>
>> Right wing?  His comments were religious.  The right wing label is
>> political.  What is the connection here?
>>
> http://www.salon.com/2014/02/22/reagans_christian_revolt_how_conservatives_hijacked_american_religion/

I'm sorry, but the fact that some people mix religion and politics does 
not mean *everyone* who believes in religion is a conservative 
politically.  Likewise it does not mean everyone who is conservative 
politically is religious.

-- 

Rick

Article: 157573
Subject: Re: Using FPGA to feed 80386
From: hamilton <hamilton@nothere.com>
Date: Tue, 16 Dec 2014 21:52:12 -0700
Links: << >>  << T >>  << A >>
On 12/16/2014 8:58 PM, rickman wrote:
> On 12/16/2014 5:34 PM, hamilton wrote:
>> On 12/16/2014 2:34 PM, rickman wrote:
>>> On 12/16/2014 1:07 PM, hamilton wrote:
>>>>>> On 12/15/2014 6:38 PM, Rick C. Hodgin wrote:  <SNIP>
>>>>
>>>> WOW, another right wing nut case !!
>>>>
>>>> Hey Rick, when you go off the deep end will you find a chocolate
>>>> shop to
>>>> visit ??
>>>
>>> Right wing?  His comments were religious.  The right wing label is
>>> political.  What is the connection here?
>>>
>> http://www.salon.com/2014/02/22/reagans_christian_revolt_how_conservatives_hijacked_american_religion/
>>
>
> I'm sorry, but the fact that some people mix religion and politics does
> not mean *everyone* who believes in religion is a conservative
> politically.  Likewise it does not mean everyone who is conservative
> politically is religious.
>
Lets see, you were wrong on Right Wing and religion,
and we see the right wing crack pots killing kids in Pakistan.

Yes, those that need to proselytize to half the world and not keep their 
whacked out ideas to themselves are just one step away from visiting 
_your_ kids school.

Religion has gone too far in its control of mind damaged people.
And there are lots out there to chose from.





Article: 157574
Subject: Re: Using FPGA to feed 80386
From: David Brown <david.brown@hesbynett.no>
Date: Wed, 17 Dec 2014 09:05:58 +0100
Links: << >>  << T >>  << A >>
On 17/12/14 05:52, hamilton wrote:
> On 12/16/2014 8:58 PM, rickman wrote:
>> On 12/16/2014 5:34 PM, hamilton wrote:
>>> On 12/16/2014 2:34 PM, rickman wrote:
>>>> On 12/16/2014 1:07 PM, hamilton wrote:
>>>>>>> On 12/15/2014 6:38 PM, Rick C. Hodgin wrote:  <SNIP>
>>>>>
>>>>> WOW, another right wing nut case !!
>>>>>
>>>>> Hey Rick, when you go off the deep end will you find a chocolate
>>>>> shop to
>>>>> visit ??
>>>>
>>>> Right wing?  His comments were religious.  The right wing label is
>>>> political.  What is the connection here?
>>>>
>>> http://www.salon.com/2014/02/22/reagans_christian_revolt_how_conservatives_hijacked_american_religion/
>>>
>>>
>>
>> I'm sorry, but the fact that some people mix religion and politics does
>> not mean *everyone* who believes in religion is a conservative
>> politically.  Likewise it does not mean everyone who is conservative
>> politically is religious.
>>
> Lets see, you were wrong on Right Wing and religion,

No, he is correct.  There is a certain group of people, particularly but
not exclusively in the USA, that classify themselves as right-wing
conservative Christians.  But there are plenty of religious people who
have different political views - or no serious political views.  For
example, Rick Hodgin has talked a great deal about his religious
beliefs, but has never mentioned politics - either he is not politically
interested, or like most of us he doesn't feel it is a natural subject
for a technical newsgroup (s.e.d. excepted, of course).  And there are
plenty of right-wingers who have not the slightest interest in religion.

> and we see the right wing crack pots killing kids in Pakistan.

You can't classify the murderers in Pakistan as right-wing - they don't
fit on the overly simplified left-wing/right-wing political model.  And
while they are religious, they were not Muslims (no matter what they
might have claimed themselves).  It's not about politics or religion -
as always, it is about power and money.  Politics and religion are just
ways to dupe the weak-willed into doing the dirty work.

> 
> Yes, those that need to proselytize to half the world and not keep their
> whacked out ideas to themselves are just one step away from visiting
> _your_ kids school.

Fortunately, that is not remotely true.  Rick's religious posts may be
annoying and out of place, but I certainly would not imagine him being
violent or threatening - it would be completely against his character.

> 
> Religion has gone too far in its control of mind damaged people.

Religion has been around for as long as human speech, as far as
anthropologists and archaeologists can tell.  People have always done
crazy and terrible things in the name of religion - it's nothing new.

> And there are lots out there to chose from.
> 





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