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Re: Wikipedia goes wrong: is this possible?

 
 
rickman
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      06-18-2013
On 6/17/2013 9:51 PM, Mark Borgerson wrote:
> In article<kpo0gf$i84$(E-Mail Removed)-darmstadt.de>,
> http://www.velocityreviews.com/forums/(E-Mail Removed)-darmstadt.de says...
>>
>> In comp.arch.embedded Jukka Marin<(E-Mail Removed)> wrote:
>>> On 2013-06-17, Ivan Shmakov<(E-Mail Removed)> wrote:
>>>> FWIW, the MCUs I've dealt with are mostly in the 0.8 USD to some
>>>> 2 USD range per piece, whether they're 8- or 32-bit. I believe
>>>> I've never bought an MCU for less than 0.5 USD a piece. But
>>>> then, I've never bought more than a dozen of a kind at any
>>>> single deal, which probably explains the difference.

>>
>>> The NXP LPC8xx series is expected to be in the 50 cent range (and up).
>>> Not bad for a 32-bit RISC in DIP8... (Yes, they do have DIP8.)

>>
>> "Expected"? Argh!
>>
>> A price you can't see for parts avaiable at mouser or digikey is not real...

>
> That's been my criteria for designing in parts for more than a decade.
> If you can't find it at one of those two, it really isn't something I
> want to put in a design. Those companies have become a my proxy
> of choice for a good purchasing agent when I am looking for quantities
> under 100 of almost anything. Granted, that I may pay a bit more per
> part---but that's nothing in comparison to designing in a part I can't
> find in time to deliver my product.


That's what I do generally, but that is no guarantee that the parts will
be there when you need them. I have a recurring problem with two chips
on a board I sell (plus a connector) and each of them have given me
trouble on the last order. I once was told by an AKM rep that 14 weeks
is a *good* lead time. LOL!

One part is a $2 part so if I have an idea an order is coming, I'll buy
the part early, but the other is a $10 part which makes it a bit pricier
to inventory. The connectors are insane. Most sources want a 12 week
lead time and a 2700 piece minimum. I found one from Sullins with 1000
piece minimum and a multiple of 1 piece beyond that with only a 4 week
lead time. That works so much better.

Just as a point of interest, I asked FCI for a sample to qualify their
equivalent part and they said they didn't have a mold for it since no
one had ordered it in that size yet! I'd have to order 2700 pieces to
get them to make the mold... lol Connectors can really suck! I had no
choice on this one, I have to mate to the customer's connector.

--

Rick
 
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Geoff
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      06-19-2013
On Mon, 17 Jun 2013 17:21:57 GMT, "paskali" <(E-Mail Removed)>
wrote:

>Andrew Smallshaw <(E-Mail Removed)> wrote:
>
>> On 2013-06-15, paskali <(E-Mail Removed)> wrote:
>> >
>> > No, there are a lot of 32bit devices, as well as i wrote there are not
>> > economical reasons to choice 8bit devices in the place of more modern 32bit's.

>>
>> Cite me one 32-bitter with a unit cost under 10 cents...
>>

>
>Euros or Dollars?


Removing all doubt that you are a troll.
 
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Phil Carmody
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      06-30-2013
David Brown <(E-Mail Removed)> writes:
> On 16/06/13 22:35, Keith Thompson wrote:
> > Malcolm McLean <(E-Mail Removed)> writes:
> >> On Saturday, June 15, 2013 6:42:31 PM UTC+1, David Brown wrote:
> >>> On 14/06/13 12:26, paskali wrote:
> >>>
> >>> No, I mean it is only occasionally acceptable to use any sort of dynamic
> >>> memory management in the sort of embedded systems I work with - and when
> >>> it is unavoidable, you use specialised functions rather than standard
> >>> malloc.
> >>>
> >> Yes, this does make life difficult.
> >>
> >> Let's say we want to calculate the median of a list of numbers. For the
> >> of view of a straightforwards, reusable, intuitive implementation of
> >> the function, the problem is unbounded. We need to create a temporary
> >> list, sort it, get the middle element, and destroy it. So we need malloc().

> >
> > You don't need to sort the entire array to compute the median.
> > You can use an algorithm similar to Quicksort, but without bothering
> > to sort any partition that doesn't include the center element.
> > (That doesn't help with the memory issue, but it's faster if you
> > don't need a sorted copy of the array for other reasons.)

>
> Of course, the question here is quite hypothetical - it is unlikely
> that you would need to find the median of a large array in a small
> embedded system. Medians of three values are quite common (as a
> simple filter to remove or reduce the effects of errors in signals),
> but they can be handled easily.


How large is "large" in the context of tiny processors?
I seem to remember the last touch-screen controller I worked
with could perform median-of-15. Given the complexity of the
controller, I considered that quite a large task.

Phil
--
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technologies and policies, then law-abiding governments should have
nothing to fear from whistleblowers.
 
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