Re: Opinions re: MCU vendors [long]



On Jan 18, 1:21 pm, D Yuniskis <not.going.to...@xxxxxxxx> wrote:
rickman wrote:
On Jan 17, 5:19 pm, D Yuniskis <not.going.to...@xxxxxxxx> wrote:
Hi,

- quality of their products

That is a pretty poorly defined metric. It reminds me of the Volvo

It is poorly defined only in the sense of how it is *measured*.
But, you *know* a quality product when you see it. You also know
*crap* when you see that!

You can "know" what you will, but if you can't tell me how you measure
the thing, it means nothing to me. Likewise, if I tell you a part or
a company is "crap" that should mean nothing to you unless I tell you
why/how I decided it was "crap". So unless you tell me what "quality"
means to you, I can't tell you which companies have it.


But then quality is not a measurable thing. Can

Sure it is! Perhaps not in some "internationally acceptable
interchangeable unit of measurement".

Ok, I'll bite. How do I measure the quality of a CPU chip or a CPU
maker?


E.g., I spent a few summers working for a (huge) hand tool manufacturer.
Part of my job was quality related. Judging the quality of their
current products and how they compare to other manufacturers of
hand tools.

And did you rate them on a scale of 1 to 10 without any sort of a
guide from your company? Or did you write about the things that you
decided made up "quality"? If neither, then what was the point of
your subjective evaluation?


Tell me, how do you *measure* the quality of a hammer? A screwdriver?
A tape rule? A saw??

Didn't I say that "quality" was not measurable... yes, I think that
is what I said.


First, you verify it meets all of your mechanical specifications.
E.g., what is the draft angle of the two faces of the (slotted)
screwdriver's tip? If it is a "cabinet tip" screwdriver, are the
*sides* of the tip parallel? Are the flutes in a Phillips
screwdriver free of buildup from the plating process? Are the
markings on a tape rule legible and accurate?

Ok, now you are evaluating it to your specs. Is that quality? What
if someone else has different specs? Does the quality change?


Second, you verify that it meets the other design specifications.
E.g., what is the (Rockwell) hardness of the shank? How thick
is the plating?

Ok, more specs...


Third, you verify that it meets the appropriate "bogo-units".
E.g., if the shank is held fast, how much torque is required
to "strip" the handle off of the shaft? If the screwdriver
tip is pushed into a precision die with a force of X, how much
torque is required to *sheer* the tip off? How many times
can you "bang" a hammer before the handle fails?

Again, more specs...


Of course, the third group are, by far, the most fun to devise
and implement. They are somewhat arbitrary. Bogus. Yet,
they each pertain to QUALITY FACTORS that the USER WILL PERCEIVE.

Ever been pissed off because you *tore* the tip off a Phillips
screwdriver? (the average man can do this *easily* for a #0
screwdriver, "with some effort" for a #1, and "only if really
determined to do so oand with the assistance of leverage
enhanceers" for a #2. #3 requires hydraulic assistance. :> )

That is interesting. So there is a tradeoff between strength of the
tip and how well the screwdriver fits your screw. So which has higher
quality?


Notice how *long* the finish on a tape rule lasts? Despite
.... snip ...
unit happens to be)

you tell me what you mean by quality? Can you define it in some terms
that someone else could respond in a way that would have meaning to
you?

Sure, obvious things:
- parts failing to meet their published specification (you would
agree that this would be "crap"?)
- parts that *technically* meet their published specification
but not "in good faith". Especially nowadays with datasheets full
of "typ" numbers. ("Yes, typically Icc is 10mA. The fact that
*all* of the devices you have purchased from us draw 100mA is
still within the (unspecified) maximum that we publish for that
part.")
But, also, remember that their "product" isn't limited to bits
of plastic made in the far east:
- documentation that is grossly and obviously incorrect
- errata that are not kept current and/or are "hidden" for
fear that someone would "think ill" of their product

If this is what you wanted to know, why didn't you ask this? By
saying "quality" you conveyed none of this to me.


I was reviewing an SiLabs part last week. Application data in
.... snip much ranting ...
of their silicon? their support? etc.

- accuracy of their documentation

My experience is that both Atmel and TI have quality documentation.
TI seems to be less willing to modify their documentation if you have
questions it does not answer. Once I got Atmel to add some info to
their SAM7 data sheets to define crystal requirements. But then they
provided a table with data points at specific frequencies that didn't
say what to do in between. I pointed out the issue and they wouldn't
even comment verbally much less clean up the issue. So I still think
they are about equal.

It seems that manufacturers are moving more into just becoming
foundries -- or IP houses (ARM). Trying to get a mix between them
seems to be difficult.

How does this impact you? If it has not changed, Xilinx and Altera
are both still pure IP houses using the big fab houses as their only/
primary source of silicon. Other companies, like TI and Atmel run
their own foundries while also designing their own chips. I have
never had a problem with either. What is it that you are saying about
it?


- ability to meet commitments

I like this one. What sort of commitments are you talking about?

Wanna buy a Z380? :>

This also means nothing to me. I am asking you to tell me what you
mean by "commitments". There are any number of types of commitments
makers make, both implied and explicit. None hold to them all.


Production? Updates? Support? If you are a small player, don't
expect too many commitments in the first place, much less holding to
them. All IC makers have a handful of major customers for whom the
sun rises and sets. Everyone else in secondary or even tertiary.

Of course! I've bought components "by the pound". And,
size shouldn't affect their *ability* to meet their commitments.
When I'm buying 1M of a particular device / year, I have a different
level of expectation (tell me I have to wait 3 years and I'll smile
and turn a new crank on thedesign so your name isn't on any of
the components). When I'm buying 1K of that same device / year,
I *don't* expect the same *timeliness* of a commitment -- *but*,
if you tell me 18 weeks, then I expect it to *be* 18 weeks and
not 24 weeks or 36 weeks or "gee, your request must have got
lost in the cracks"!

Well you are living in a fantasy world. It has been more than once
that I was quoted (not promised) parts and they failed to arrive
because a bigger fish ate them. The disti said "sorry" and did I
still want to keep the PO open for delivery in another month. It
happens because if there is a hiccup, they will piss you off rather
than the big guy. What would you do, piss of your new, very small
customer, or your old, established customer that is 30% of your annual
business?

.... snip ...


Thanks for your comments!
--don

Rick
.



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