Another Newbie USB Hardware Question

Look at page 23 here:

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Can i replace the TPS2042 with one of these:

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???

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....

Reply to
Paul
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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

Reply to
Paul

Paul wrote: ( snipped-for-privacy@gmail.com)

One (or both) of you needs a more descriptive name.

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Reply to
CBFalconer

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

Reply to
Paul

Yes, you can use it.

Next question.

Paul

Reply to
Paul

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.

Reply to
David Brown

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?

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Reply to
Chris H

] ...................

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

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Reply to
Chris H

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.

See "the September that never ended"

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John Devereux
Reply to
John Devereux

url?

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.

Reply to
sky465nm

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

Reply to
David Brown

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".

Reply to
David Brown

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.

Reply to
Jeff Strickland

.

AT1275.pdf

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!

Reply to
Paul

.

AT1275.pdf

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......

Reply to
Paul

... snip ...

... snip ...

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.

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Reply to
CBFalconer

They just did in detail.

Robert

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Reply to
Robert Adsett

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.

Reply to
David Brown

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 , Pin 2 is , 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, "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.

Reply to
Jeff Strickland

You're not an engineer.

Reply to
Paul Burke

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