Chip with simple program for Toy

[Sam Wormley]

On 3/18/10 3:27 AM, Magnetic wrote:

I give 50% probability that CERN will explode the Earth in a couple of
weeks. The 30-th of March it will collide protons with the energy
2*3.5 TeV.
The 30-th of March is the most probable day of Dangerous Droplet
creation.
The 1-st of April is the most probable day of our total start to
stars.

http://darkenergy.narod.ru/

Now you have something with a real probability to worry about! Body
heat may draw particles into breathing range!

Computer simulations suggest thermal plumes may trap microbes, pollen
and dust near a person’s head.

http://www.sciencenews.org/view/generic/id/57393/title/Body_heat_may_draw_particles_into_breathing_range

 

[Francois Grieu]

John Fields wrote :

On Thu, 18 Mar 2010 08:23:51 +0100, Francois Grieu <fgrieu@gmail.com
wrote:

Hello,

I'm struggling to find a simple schematic to implement this two-inputs (A B),
one output (X) function, using 74HC building blocks.

In words:
- X is high whenever A and B are both high;
- if A is high when B goes low, X tracks B until A and B are both high;
- if A is low when B goes low, X remains high.

A-----------\__________________/--------\_______/---\___/--------------

B------\________/---\_____/-----------------\______________/-----------

X-------\________/---\_____/-------------------------------------------


The B to X delays must be low, in the order of 50 ns max @ 5V, for both
transitions. A / B setup times are in the order of 200 ns min.

Any idea ? So far anything I can think of has some ugly delay/monostable.


Unless I'm missing something, and you're talking something other than
combinatorial logic,

I'm indeed talking something other than pure combinatorial logic.
The state of the output X depends on previous history of the inputs,
not only on the present state of the inputs.

My previous "words" statement was imprecise, and one case not
illustrated in the diagram; things should have been:
- X is high and the system reset whenever A and B are both high;
- if A is high when B goes low, then X shall track B until system reset;
- otherwise, X shall remain high.

A--------\__________________/----\_______/---\___/-------\___________/----

B----\________/----\___/-------------\_______________/-------\___/--------

X-----\________/----\___/-------------------------------------------------


In precisely equivalent words, X is to be high if and only if
- B is high
OR
- there has been no high to low transition of B with A high since
the last time the condition (A and B) held.

The B to X delays must be low, in the order of 50 ns max @ 5V, for both
transitions. There is only a single change of either A or B in any
200 ns time period.

Francois Grieu

 

[Uwe Hercksen]

Francois Grieu schrieb:

Any idea ? So far anything I can think of has some ugly delay/monostable.

Hello,

a simple solution using only gates and no delay or monostables is
impossible.
But may be there is a solution using gates and edge triggerd flipflops.
If you use a falling edge triggerd flipflop and connect A to the clock
input and B to the data input, the Q output remains high if A goes low
before B. But you get a problem with the second fallig edge of A while B
is low.

Bye

 

[MooseFET]

On Mar 18, 12:23 am, Francois Grieu <fgr...@gmail.com> wrote:

Hello,

I'm struggling to find a simple schematic to implement this two-inputs (A B),
one output (X) function, using 74HC building blocks.

In words:
- X is high whenever A and B are both high;
- if A is high when B goes low, X tracks B until A and B are both high;
- if A is low when B goes low, X remains high.

A-----------\__________________/--------\_______/---\___/--------------

B------\________/---\_____/-----------------\______________/-----------

X-------\________/---\_____/-------------------------------------------

The B to X delays must be low, in the order of 50 ns max @ 5V, for both
transitions. A / B setup times are in the order of 200 ns min.

Any idea ? So far anything I can think of has some ugly delay/monostable.

TIA,

  Francois Grieu

74HC74:
1-flip-flop set if B falls while A is high.
2-flip-flop cleared if both A and B high

1
This means that 3 things need to be anded and fed to the clock
A, B/ and Q/. It can also be done with the D input fed with
A or Q


2
This is a 2 input nand feeding the reset


Now just or Q/ with B to make the output

 

[Tim Wescott]

Francois Grieu wrote:

Hello,

I'm struggling to find a simple schematic to implement this two-inputs
(A B),
one output (X) function, using 74HC building blocks.

In words:
- X is high whenever A and B are both high;
- if A is high when B goes low, X tracks B until A and B are both high;
- if A is low when B goes low, X remains high.

What happens when A goes low?

A-----------\__________________/--------\_______/---\___/--------------

B------\________/---\_____/-----------------\______________/-----------

X-------\________/---\_____/-------------------------------------------


The B to X delays must be low, in the order of 50 ns max @ 5V, for both
transitions. A / B setup times are in the order of 200 ns min.

Any idea ? So far anything I can think of has some ugly delay/monostable.

TIA,

Francois Grieu

It needs internal states, and it either needs to be clocked damn fast or
(as someone mentioned) it needs those internal states to feed gates that
control X from B.

How many internal states do you need? Can you clock this thing from an
asynchronous clock or does it have to be clocked by the edges of A and B?

--
Tim Wescott
Control system and signal processing consulting
www.wescottdesign.com

 

[Francois Grieu]

Tim Wescott a écrit :

Francois Grieu wrote:
Hello,

I'm struggling to find a simple schematic to implement this two-inputs
(A B),
one output (X) function, using 74HC building blocks.

In words:
- X is high whenever A and B are both high;
- if A is high when B goes low, X tracks B until A and B are both high;
- if A is low when B goes low, X remains high.

What happens when A goes low?

That alone never changes the output.

My previous "words" statement was a bit imprecise, and one case not
illustrated in the diagram; things should have been:
- X is high and the system reset whenever A and B are both high;
- if A is high when B goes low, then X shall track B until system reset;
- otherwise, X shall remain high.

A--------\__________________/----\_______/---\___/-------\___________/----

B----\________/----\___/-------------\_______________/-------\___/--------

X-----\________/----\___/-------------------------------------------------

The B to X delays must be low, in the order of 50 ns max @ 5V, for both
transitions. A / B setup times are in the order of 200 ns min.

Any idea ? So far anything I can think of has some ugly delay/monostable.

TIA,

Francois Grieu

It needs internal states, and it either needs to be clocked damn fast or
(as someone mentioned) it needs those internal states to feed gates that
control X from B.

Yes.

How many internal states do you need?

Just one bit S: has there been a high-to-low transition on B with A set
since the last time the condition A&B held. Then X = B | !S.

Can you clock this thing from an asynchronous clock

No, because the single clock at hand is not fast enough, and besides B
has no defined phase relationship with that clock.

or does it have to be clocked by the edges of A and B?

That's what I'm looking after.


Francois Grieu

 

[whit3rd]

On Mar 18, 12:23 am, Francois Grieu <fgr...@gmail.com> wrote:

I'm struggling to find a simple schematic to implement this two-inputs (A B),
one output (X) function, using 74HC building blocks.

In words:
- X is high whenever A and B are both high;

So, X = A * B + C
(A or B anded with any function C...

- if A is high when B goes low, X tracks B until A and B are both high;

Event B lowgoing while A sets flipflop, reset only when A*B asserts
high
and the C function is defined here as B while that flipflop is set

- if A is low when B goes low, X remains high.

That, I don't get. X can only remain high if it were high to begin
with...
but maybe this just means C = high when flipflop is not set?

 

[Francis Burton]

In article <hnr6ku$6ci$1@blue.rahul.net>,
Steve Pope <spope33@speedymail.org> wrote:

I give 50% probability that CERN will explode the Earth in
a couple of weeks.

But under a multiverse hypothesis, we would never know it did.
70% of physicists believe in some version of multiverse theory.

At least in this universe. In another, it's only 20%.

Francis

 

[whit3rd]

On Mar 18, 12:23 am, Francois Grieu <fgr...@gmail.com> wrote:

I'm struggling to find a simple schematic to implement this two-inputs (A B),
one output (X) function, using 74HC building blocks.
In words:
- X is high whenever A and B are both high;

So, X = (A .and. B) .or. C

(A .and. B .or.-ed with any function C...

- if A is high when B goes low, X tracks B until A and B are both high;

Event B lowgoing while A sets flipflop, reset only when A .and. B
asserts
high; this will call for an edge-triggered flipflop, with reset.
74HC74?
and the C function is defined here as B while that flipflop is set

(74HC74 trigger = .not. B, D input = A,reset input = A .and. B;
outputs Q and .not. Q)

- if A is low when B goes low, X remains high.

That, I don't get. X can only remain high if it were high to begin
with...
but maybe this just means C = high when flipflop is not set?

C = .not. Q .or. ( Q .and. B)

The startup state of the flipflop is undetermined, it's a good idea to
use
a master set or reset system signal to make it determinate. It's
also
a very good idea to put a Schmitt trigger (inverter or gate) on the
input clock
signal, to keep it from doing something ... odd.

 

[krw@att.bizzzzzzzzzzzz]

On Thu, 18 Mar 2010 07:21:42 -0500, John Fields
<jfields@austininstruments.com> wrote:

On Thu, 18 Mar 2010 01:27:13 -0700 (PDT), Magnetic
magnetic.trap@yandex.ua> wrote:


I give 50% probability that CERN will explode the Earth in a couple of
weeks. The 30-th of March it will collide protons with the energy
2*3.5 TeV.
The 30-th of March is the most probable day of Dangerous Droplet
creation.
The 1-st of April is the most probable day of our total start to
stars.

---
How about taking bets?

You could make a fortune if you were right!!!

Can I have a piece of your action, John?

Oh, but wait...

Ssshhh! He'll never figure it out.

 

[Jasen Betts]

On 2010-03-18, Francois Grieu <fgrieu@gmail.com> wrote:

Jasen Betts wrote:
On 2010-03-18, Francois Grieu <fgrieu@gmail.com> wrote:

I'm struggling to find a simple schematic to implement this two-inputs
(A B), one output (X) function, using 74HC building blocks.

In words:
- X is high whenever A and B are both high;
- if A is high when B goes low, X tracks B until A and B are both high;
- if A is low when B goes low, X remains high.

A-----------\__________________/--------\_______/---\___/--------------

B------\________/---\_____/-----------------\______________/-----------

X-------\________/---\_____/-------------------------------------------


The B to X delays must be low, in the order of 50 ns max @ 5V, for both
transitions. A / B setup times are in the order of 200 ns min.

Any idea ? So far anything I can think of has some ugly delay/monostable.


for minimum propogation delay you need to do it like this.

A -----::::::::::::::::: or gate
::state machine::------. __
B -+---::::::::::::::::: `--| \
| ) 1 >--------
| .--|__/
`--------------------------'

Agreed.

it looks like the state machine is an S-R flip-flop

Seems reasonable...

with (A & B) feeding RESET and (B & !A) feeding SET

Unless I err, the second pulse is missing from X.

A----------------\__________________/-------\_______/---\___/---------

B-----------\________/---\_____/----------------\______________/------

R=A&B-------\_______________________/-------\__________________/------

S=B&!A_______________/---\_____/----\_______/---\_____________________

SR___________________/--------------\_______/------------------\______

X'=B|SR------\________/-----------------------------------------------

X------------\________/---\_____/-------------------------------------

The SET condition seems overly inclusive. But I have trouble pinpointing
an appropriate condition. I think it can't be a purely combinatorial
function of A and B.

You're right. I was thinking on this further, more state is needed so
that the flipflop is only set when A goes from high to low while B is high.

--














































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[Darwin123]

On Mar 25, 12:42 pm, Magnetic <magnetic.t...@yandex.ua> wrote:

Idiots, we all will be killed in a couple of days.
All!
Do you understand this?
The world ended 16 March 2010, just as you predicted. Your body has

been reduced to plasma in a magnetic hole. Your soul has persisted.
You are now in Hell.

 

[jandrm]

Darwin123 wrote:

On Mar 25, 12:42 pm, Magnetic <magnetic.t...@yandex.ua> wrote:
Idiots, we all will be killed in a couple of days.
All!

Well... smoke if u got em

 

[Jon]

"jandrm" <example@com.com> wrote in message
news:hoh2uc$to5$1@news.mixmin.net...

Darwin123 wrote:

On Mar 25, 12:42 pm, Magnetic <magnetic.t...@yandex.ua> wrote:
Idiots, we all will be killed in a couple of days.
All!


Well... smoke if u got em

.....You can tune a piano but you can't tuna fish.



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[Michael A. Terrell]

Jon wrote:

"jandrm" <example@com.com> wrote in message
news:hoh2uc$to5$1@news.mixmin.net...
Darwin123 wrote:

On Mar 25, 12:42 pm, Magnetic <magnetic.t...@yandex.ua> wrote:
Idiots, we all will be killed in a couple of days.
All!


Well... smoke if u got em

....You can tune a piano but you can't tuna fish.

So? They'll work for scale...


--
Lead free solder is Belgium's version of 'Hold my beer and watch this!'

 

[krw@att.bizzzzzzzzzzzz]

On Fri, 26 Mar 2010 15:28:18 -0400, "Michael A. Terrell"
<mike.terrell@earthlink.net> wrote:

Jon wrote:

"jandrm" <example@com.com> wrote in message
news:hoh2uc$to5$1@news.mixmin.net...
Darwin123 wrote:

On Mar 25, 12:42 pm, Magnetic <magnetic.t...@yandex.ua> wrote:
Idiots, we all will be killed in a couple of days.
All!


Well... smoke if u got em

....You can tune a piano but you can't tuna fish.


So? They'll work for scale...

I highly doubt it. They worked a local pub when I was in college, but I think
they'd want a little more now.

 

[John Larkin]

On Thu, 25 Mar 2010 14:56:10 -0700 (PDT), Darwin123
<drosen0000@yahoo.com> wrote:

On Mar 25, 12:42 pm, Magnetic <magnetic.t...@yandex.ua> wrote:
Idiots, we all will be killed in a couple of days.
All!
Do you understand this?
The world ended 16 March 2010, just as you predicted. Your body has
been reduced to plasma in a magnetic hole. Your soul has persisted.
You are now in Hell.

Well, I'm still alive. Are you?

John

 

[Jon]

<krw@att.bizzzzzzzzzzzz> wrote in message
news:bakqq59i73v041nc9t6fcclg4qvbmo2prj@4ax.com...

On Fri, 26 Mar 2010 15:28:18 -0400, "Michael A. Terrell"
mike.terrell@earthlink.net> wrote:


Jon wrote:

"jandrm" <example@com.com> wrote in message
news:hoh2uc$to5$1@news.mixmin.net...
Darwin123 wrote:

On Mar 25, 12:42 pm, Magnetic <magnetic.t...@yandex.ua> wrote:
Idiots, we all will be killed in a couple of days.
All!


Well... smoke if u got em

....You can tune a piano but you can't tuna fish.


So? They'll work for scale...

I highly doubt it. They worked a local pub when I was in college, but I
think
they'd want a little more now.

Not always, some 12 years back approximately, REO was playing at a local
high school dance in the Dayton Ohio area. The radio DJ was yapping about
how poorly their career had been since 'High in Fidelity' was released that
they had to resort to high school socials.

It did seem very strange that they should play at that venue but I'm sure
the
residuals are quite good.






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[Michael A. Terrell]

"krw@att.bizzzzzzzzzzzz" wrote:

On Fri, 26 Mar 2010 15:28:18 -0400, "Michael A. Terrell"
mike.terrell@earthlink.net> wrote:


Jon wrote:

"jandrm" <example@com.com> wrote in message
news:hoh2uc$to5$1@news.mixmin.net...
Darwin123 wrote:

On Mar 25, 12:42 pm, Magnetic <magnetic.t...@yandex.ua> wrote:
Idiots, we all will be killed in a couple of days.
All!


Well... smoke if u got em

....You can tune a piano but you can't tuna fish.


So? They'll work for scale...

I highly doubt it. They worked a local pub when I was in college, but I think
they'd want a little more now.

You had tuna working at a pub? I'll bet that really stunk.


--
Lead free solder is Belgium's version of 'Hold my beer and watch this!'

 

[krw@att.bizzzzzzzzzzzz]

On Sat, 27 Mar 2010 02:15:32 -0400, "Michael A. Terrell"
<mike.terrell@earthlink.net> wrote:

"krw@att.bizzzzzzzzzzzz" wrote:

On Fri, 26 Mar 2010 15:28:18 -0400, "Michael A. Terrell"
mike.terrell@earthlink.net> wrote:


Jon wrote:

"jandrm" <example@com.com> wrote in message
news:hoh2uc$to5$1@news.mixmin.net...
Darwin123 wrote:

On Mar 25, 12:42 pm, Magnetic <magnetic.t...@yandex.ua> wrote:
Idiots, we all will be killed in a couple of days.
All!


Well... smoke if u got em

....You can tune a piano but you can't tuna fish.


So? They'll work for scale...

I highly doubt it. They worked a local pub when I was in college, but I think
they'd want a little more now.


You had tuna working at a pub? I'll bet that really stunk.

No, they had a piano.