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Another Newbie USB Hardware Question

P

Paul

Jan 1, 1970
0
Look at page 23 here:

http://www.toradex.com/downloads/Colibri_EvaluationBoard_Schematics_Rev2.1.pdf


Can i replace the TPS2042 with one of these:

http://www.analogictech.com/products/digitalfiles/AAT1275.pdf


???

They look to be performing the same functions, giving
the host controller an ENABLE line, and also giving an
Over-current Fault or Flag condition. So it looks like
i should be able to replace the TPS2042 with the AAT1275,
even though the former chip is only a switch, and not
a regulator too, right?


Thanks in advance....
 
P

Paul

Jan 1, 1970
0
Paul said:
Look at page 23 here:

http://www.toradex.com/downloads/Colibri_EvaluationBoard_Schematics_Rev2.1.pdf


Can i replace the TPS2042 with one of these:

http://www.analogictech.com/products/digitalfiles/AAT1275.pdf


???

They look to be performing the same functions, giving
the host controller an ENABLE line, and also giving an
Over-current Fault or Flag condition. So it looks like
i should be able to replace the TPS2042 with the AAT1275,
even though the former chip is only a switch, and not
a regulator too, right?


Thanks in advance....

I'm all for helping you, but the thing is, this isn't how
you approach engineering. You look at all the requirements,
and then decide how the existing design meets those requirements,
and which parts have to be changed. Or whether, in fact, the
Colibri is so far removed from what you want to do, to be a
poor starting point.

Your question implies a change to the power distribution system.
As if, certain rails are not available to the thing you are
trying to design. You need to examine all the subsystems,
their power requirements. Also, why the designer of the
existing design, chose to do his power conversion and
distribution in a particular way. You make a list of all
the power requirements for the design, and *then* make
the call as to where to put boost or buck converters etc.
Maybe if other parts of the design need +5V, you need a
bigger converter.

You'll save yourself a lot of work, if you study the design
first, and save schematic edits, for when all of your planning
is finished. Making a change here, and a change there, may not
cut it. And would be the mark of an amateur.

The AAT1275 implies you want to run a USB port, off a battery.
It seems a rather radical shift, and suggests you're about
to pepper us with 20 more, context free, component change
requests.

Also, I expect you'll soon be asking "can anybody pick out
a 2.2uH inductor for me?". The answer to that is "No". :)
I hate picking inductors for stuff. Page 11 of the datasheet,
goes through some of the technical issues. For the more
complex boost or buck switchers, some designers prototype
the design first, and optimize it (perhaps changing inductors,
if they don't like how the prototype is behaving). In this
case, since the output of the AAT1275 is not powering a part
of the main board, you could use the design itself as your
prototyping platform, paying for your mistakes with a PCB respin.

Some component manufacturers, make available evaluation boards,
and maybe you could get an eval board with the AAT1275 on it.
The advantage there, is you'd get to see the inductor they
chose, and also have a platform for testing the circuit before
using it. (Loading the thing up to 500mA, and seeing whether
it regulates properly.) Of course, an eval board costs money.

What happens with some switching converter designs, is the
designer poorly estimates the power requirements of the
load, and the switching converter is optimized for one
particular load point. Suddenly, the designer discovers
what a poor choice the thing is, because it is so close
to overload, or not being able to drive the load. I can't
speak to the AAT1275, and how well it does its job, but
adding a component like that to a design, increase the
"risk" factor.

Paul
 
P

Paul

Jan 1, 1970
0
I'm all for helping you, but the thing is, this isn't how
you approach engineering. You look at all the requirements,
and then decide how the existing design meets those requirements,
and which parts have to be changed. Or whether, in fact, the
Colibri is so far removed from what you want to do, to be a
poor starting point.

Your question implies a change to the power distribution system.
As if, certain rails are not available to the thing you are
trying to design. You need to examine all the subsystems,
their power requirements. Also, why the designer of the
existing design, chose to do his power conversion and
distribution in a particular way. You make a list of all
the power requirements for the design, and *then* make
the call as to where to put boost or buck converters etc.
Maybe if other parts of the design need +5V, you need a
bigger converter.

You'll save yourself a lot of work, if you study the design
first, and save schematic edits, for when all of your planning
is finished. Making a change here, and a change there, may not
cut it. And would be the mark of an amateur.

The AAT1275 implies you want to run a USB port, off a battery.
It seems a rather radical shift, and suggests you're about
to pepper us with 20 more, context free, component change
requests.

Also, I expect you'll soon be asking "can anybody pick out
a 2.2uH inductor for me?". The answer to that is "No". :)
I hate picking inductors for stuff. Page 11 of the datasheet,
goes through some of the technical issues. For the more
complex boost or buck switchers, some designers prototype
the design first, and optimize it (perhaps changing inductors,
if they don't like how the prototype is behaving). In this
case, since the output of the AAT1275 is not powering a part
of the main board, you could use the design itself as your
prototyping platform, paying for your mistakes with a PCB respin.

Some component manufacturers, make available evaluation boards,
and maybe you could get an eval board with the AAT1275 on it.
The advantage there, is you'd get to see the inductor they
chose, and also have a platform for testing the circuit before
using it. (Loading the thing up to 500mA, and seeing whether
it regulates properly.) Of course, an eval board costs money.

What happens with some switching converter designs, is the
designer poorly estimates the power requirements of the
load, and the switching converter is optimized for one
particular load point. Suddenly, the designer discovers
what a poor choice the thing is, because it is so close
to overload, or not being able to drive the load. I can't
speak to the AAT1275, and how well it does its job, but
adding a component like that to a design, increase the
"risk" factor.

Paul


Ok, now will someone with REAL knowledge/experience
in USB chime in and actually answer my question?
 
P

Paul

Jan 1, 1970
0
Paul said:
Ok, now will someone with REAL knowledge/experience
in USB chime in and actually answer my question?

Yes, you can use it.

Next question.

Paul
 
D

David Brown

Jan 1, 1970
0
Paul said:
Ok, now will someone with REAL knowledge/experience
in USB chime in and actually answer my question?

Is it just me, or does this guy Paul Quiller represent a new low with
his antisocial responses?

Paul Nospam clearly spent a fair amount giving you (Paul Quiller)
helpful advice, both in this thread and a previous thread. In both
threads, when you couldn't understand the help you were given, you
responded by insulting the poster. You don't just need to go back to
college and learn how to do electronics engineering (hint - it's not
just cutting and pasting from evaluation cards) - you need to go back to
kindergarten and learn how to play nicely with other children.
 
C

Chris H

Jan 1, 1970
0
David Brown said:
Is it just me, or does this guy Paul Quiller represent a new low with
his antisocial responses?

Not quite... the new low is that I am going to have to publicly agree
with you again :)
Paul Nospam clearly spent a fair amount giving you (Paul Quiller)
helpful advice, both in this thread and a previous thread. In both
threads, when you couldn't understand the help you were given, you
responded by insulting the poster. You don't just need to go back to
college and learn how to do electronics engineering (hint - it's not
just cutting and pasting from evaluation cards) - you need to go back
to kindergarten and learn how to play nicely with other children.

This is getting more common. There have been a couple of threads where
new people have also said I don't care about the social norms and
"rules" of this group I am going to do my own thing and if you don't
like it you can go away.

It is one thing old hands arguing for a change but newbies who don't
know how and why things have developed the way they have just seem to be
diving in with no social graces at all. You can tell the don't get out
enough because if they behaved that way in a bar they would be in
hospital more than the bar!

The other thing is that many do not bother to look in the manuals much
less the online help at the tool/chip vendors web site.

How come they can find this group on Usenet (ITS NOT A GOOGLE GROUP
Google is just the front end viewer) but cant search the Internet
intelligently?

I can recall back in the mid 1990's when AOL dumped its people onto the
net thereby causing AOL users to be known as Arse-holes On Line. Now it
seems that every halfwit and social miss-fit can find there way here and
behave in a way they could not in a real social interaction.

Incidentally David I had already drafted most of my next ESE column on
this very subject. It seems to have got a lot worse over the last few
months. Perhaps it is just the socially inadequate have coincided with
a new term at collage and we seem to be having more of them.

I recall some one else had a go about this a year back?
 
C

Chris H

Jan 1, 1970
0
In message
I'm all for helping you, but the thing is, this isn't how
you approach engineering. You look at all the requirements,
]
....................

adding a component like that to a design, increase the
"risk" factor.

Paul


Ok, now will someone with REAL knowledge/experience
in USB chime in and actually answer my question?

I think that was the wrong answer to some good advice.
 
J

John Devereux

Jan 1, 1970
0
On s.e.d.? I think I can safely say we've gone lower! :)

But I agree, it's pretty bad - the worst I can recall in
comp.arch.embedded actually.
Not quite... the new low is that I am going to have to publicly agree
with you again :)


This is getting more common. There have been a couple of threads
where new people have also said I don't care about the social norms
and "rules" of this group I am going to do my own thing and if you
don't like it you can go away.

It is one thing old hands arguing for a change but newbies who don't
know how and why things have developed the way they have just seem to
be diving in with no social graces at all. You can tell the don't
get out enough because if they behaved that way in a bar they would be
in hospital more than the bar!

The other thing is that many do not bother to look in the manuals much
less the online help at the tool/chip vendors web site.

How come they can find this group on Usenet (ITS NOT A GOOGLE GROUP
Google is just the front end viewer) but cant search the Internet
intelligently?

I can recall back in the mid 1990's when AOL dumped its people onto
the net thereby causing AOL users to be known as Arse-holes On Line.
Now it seems that every halfwit and social miss-fit can find there way
here and behave in a way they could not in a real social interaction.

Incidentally David I had already drafted most of my next ESE column on
this very subject. It seems to have got a lot worse over the last few
months. Perhaps it is just the socially inadequate have coincided
with a new term at collage and we seem to be having more of them.

I recall some one else had a go about this a year back?

See "the September that never ended"

<http://en.wikipedia.org/wiki/Eternal_September>
 
Incidentally David I had already drafted most of my next ESE column on

url?
See "the September that never ended"

Well if schools allow first 16-18 year olds (college). Then add 13-15 years
old aswell (elementary). And add millions of people without academic connection
whatsoever from the strict commercial sphere. The end result can't be an
suprise. Can't say 99% of the people in elementary I came as across as even
trying to have reflection over matters or vision. And now they creeped back in.
 
D

David Brown

Jan 1, 1970
0
John said:
On s.e.d.? I think I can safely say we've gone lower! :)

I didn't notice that the cross-posting to s.e.d. - that group has its
own special rules for behaviour!
 
D

David Brown

Jan 1, 1970
0
Chris said:
Not quite... the new low is that I am going to have to publicly agree
with you again :)


This is getting more common. There have been a couple of threads where
new people have also said I don't care about the social norms and
"rules" of this group I am going to do my own thing and if you don't
like it you can go away.

It is one thing old hands arguing for a change but newbies who don't
know how and why things have developed the way they have just seem to be
diving in with no social graces at all. You can tell the don't get out
enough because if they behaved that way in a bar they would be in
hospital more than the bar!

As that great Glaswegian philosopher Billy Connolly says, "hingen's too
good for these people - it's a good kick up the arse they need".
 
J

Jeff Strickland

Jan 1, 1970
0
David Brown said:
Is it just me, or does this guy Paul Quiller represent a new low with his
antisocial responses?

I can't even tell what he wants to do. It looks like he is reinventing the
wheel. If I understand this right, all he needs is to go out and buy a USB
hub.

That, and to stop insulting people that give him far more information in a
response then he gives in a question.
 
P

Paul

Jan 1, 1970
0
Is it just me, or does this guy Paul Quiller represent a new low with
his antisocial responses?

Paul Nospam clearly spent a fair amount giving you (Paul Quiller)
helpful advice, both in this thread and a previous thread.  In both
threads, when you couldn't understand the help you were given, you
responded by insulting the poster.  You don't just need to go back to
college and learn how to do electronics engineering (hint - it's not
just cutting and pasting from evaluation cards) - you need to go back to
kindergarten and learn how to play nicely with other children.

oh, so it's ok for the other Paul to insult me
with a huge "this isn't how you do engineering" lecture,
but i cannot insult him back for not answering/understanding my
question? F-that!
 
P

Paul

Jan 1, 1970
0
Is it just me, or does this guy Paul Quiller represent a new low with
his antisocial responses?

Paul Nospam clearly spent a fair amount giving you (Paul Quiller)
helpful advice, both in this thread and a previous thread.  In both
threads, when you couldn't understand the help you were given, you
responded by insulting the poster.  You don't just need to go back to
college and learn how to do electronics engineering (hint - it's not
just cutting and pasting from evaluation cards) - you need to go back to
kindergarten and learn how to play nicely with other children.

You write this as if you have NEVER copied and pasted
parts of someone else's design: TOTAL B.S.

I suppose you'll have me re-invent the wheel, too, eh?

Maybe you have the time to do that one......
 
C

CBFalconer

Jan 1, 1970
0
Paul said:
Yes, you can use it.

Next question.

There are at least two Pauls in this thread. It would be helpful
if one or more of them altered his name to include at least a last
name initial. Ignoring the politeness issue.
 
R

Robert Adsett

Jan 1, 1970
0
Ok, now will someone with REAL knowledge/experience
in USB chime in and actually answer my question?

They just did in detail.

Robert
 
D

David Brown

Jan 1, 1970
0
Paul said:
oh, so it's ok for the other Paul to insult me
with a huge "this isn't how you do engineering" lecture,
but i cannot insult him back for not answering/understanding my
question? F-that!

Paul Nospam was giving helpful advice, based on what you wrote - your
suggestions were *not* how to do engineering. He wasn't insulting you -
he was stating the facts. The same applies to other helpful posters
(such as Andrew Smallshaw) on previous threads. These are experienced
engineers offering their time and knowledge to help a newcomer get
started. Your insults were petty, unprovoked and childish. If people
don't understand your questions, it is up to *you* to explain them more
clearly.

And even if Paul Nospam *had* insulted you, it's still OK for him but
not for you. He is the teacher in this thread - you are the humble
student. If accepting insults is the cost you have to pay to learn from
others to help *you* with *your* problem, then you have to put up with
that. If I post a question that makes me look like an idiot, and
someone calls me an idiot and tells me a better way to do things, then
I'm happy with that.
 
P

Paul

Jan 1, 1970
0
David said:
Paul Nospam was giving helpful advice, based on what you wrote - your
suggestions were *not* how to do engineering.

oh, there's only one way to engineer? Lemme guess,
YOUR WAY.



He wasn't insulting you -
he was stating the facts. The same applies to other helpful posters
(such as Andrew Smallshaw) on previous threads. These are experienced
engineers offering their time and knowledge to help a newcomer get
started. Your insults were petty, unprovoked and childish. If people
don't understand your questions, it is up to *you* to explain them more
clearly.

And even if Paul Nospam *had* insulted you, it's still OK for him but
not for you. He is the teacher in this thread - you are the humble
student. If accepting insults is the cost you have to pay to learn from
others to help *you* with *your* problem, then you have to put up with
that. If I post a question that makes me look like an idiot, and
someone calls me an idiot and tells me a better way to do things, then
I'm happy with that.

BULLSH**.

Good teachers are respectful when teaching, always.

Assholes teaches first begin by telling the student how
dumb and foolish and stupid they are, THEN spout off....
usually without answering the question because they aren't
as knowledgable as they think!

This is why most engineers are afraid to ask questions:
THEY DON"T WANT TO LOOK BAD....THEY WANT TO APPEAR
ALL-KNOWING. BS!
 
J

Jeff Strickland

Jan 1, 1970
0
Paul said:
oh, there's only one way to engineer? Lemme guess,
YOUR WAY.



He wasn't insulting you -

BULLSH**.

Good teachers are respectful when teaching, always.

You sir, are a complete idiot. USB by definition is a certain design, any
other design is not USB.

If you want a USB device to do a particular thing, it must do it within the
confines of the specification. The spec is widely available, and was given
to you. You might not like it, but it was given.

I don't know what you are trying to do, and don't care. But it strikes me,
and everybody else, that you asked a question then argued the answer is
wrong. You are the one lacking respect.

USB is a spec. The spec defines the pinouts on the various connectors by
signals that are carried and by physical size and shape. The spec says that
Pin 1 is always <whatever>, Pin 2 is <whatever>, and so on.

I don't even know what the question is, and I have arrived at the fact that
you are an idiot by the responses you have given to people that are trying
to help. Until you began hurling insults around, I did not think anybody was
dissing you.

Clearly the answer you received to your original post provided far more
information than your question gave, and your first response was,
<paraphrasing> "Okay, anybody that really knows want to take a stab at
this?" When the answer was very detailed. I read the question you posted,
and my instinct was that you need a USB hub -- all of the wheel-engineering
has already been done yet you appear to want to reinvent the wheel.
 
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