🚀 go-pugleaf

On Sat, 31 Oct 2009 09:08:40 +1100, "David L. Jones"
<altzone@gmail.com> wrote:

>Jon Kirwan wrote:
>> On Fri, 30 Oct 2009 15:43:58 +0000, Raveninghorde
>> <raveninghorde@invalid> wrote:
>>
>>> On Fri, 30 Oct 2009 06:52:49 -0700 (PDT), MooseFET
>>> <kensmith@rahul.net> wrote:
>>>
>>>> On Oct 30, 4:57 am, Al Borowski <al.borow...@gmail.com> wrote:
>>>>>> Briefly, the Modified-Harvard architecture used in the PIC devices
>>>>>> separates the program memory from the data memory, in other words
>>>>>> separates the ROM/FLASH program memory from the RAM.
>>>>>
>>>>> [...]
>>>>>
>>>>> Yes, but there's more to to a uC core then choosing between
>>>>> Harvard or
>>>>> Von Neumann. I think most of the PICs quirks come from the other
>>>>> decisions made.
>>>>>
>>>>> The PIC (up to 16 bit cores anyway) is an accumulator architecture
>>>>> -
>>>>> you have to funnel everything through the W register.
>>>>
>>>> Going with accumulator model allowed Microchip to make the processor
>>>> with fewer transistors. It is a trade off that can break either way.
>>>> If you have a limit on the chip size you can make a higher
>>>> performance processor that is harder to program.
>>>>
>>>>
>>>> [....]
>>>>> in the 16 bit core thankfully). Personally, I think the most
>>>>> annoying
>>>>> thing about programming PICs in assembly are the btfsc (test a bit
>>>>> in 'file', skip the next instruction if it's clear) and btfss
>>>>> (same thing
>>>>> but skip if set) instructions. Why they couldn't just call these
>>>>> ifbit
>>>>> and ifnbit, I don't know :-)
>>>>
>>>> Does ifbit mean skip if the bit is set or do the instruction if the
>>>> bit is set?
>>>>
>>>>>
>>>>> Back to the OP, great job Microchip on the video. It's a nice
>>>>> contrast
>>>>> to TI, who recently sent misleading DMCA notices to people who
>>>>> tried
>>>>> installing after-market OSs on their graphics calculators
>>>>> (http://news.cnet.com/8301-30685_3-10374284-264.html)
>>>>>
>>>>> Cheers,
>>>>>
>>>>> A;
>>>>
>>>> I still prefer the 8051.  It is way better.
>>>> [ducks]
>>>
>>> So do I. The 8051 family was/is great.
>>
>> I'm using one from SiLabs, right now.  Last 8051 project I did was
>> back in the early 1980's.  (Still have a box of about 100 80C32 chips
>> in perfect shape.)  For this app, I needed a much faster floating
>> point ln(x) function (achieved under 18 microseconds) and found myself
>> spending some time coding assembly on it.  No question in my mind that
>> this processor was designed with hand-coded assembly in mind, though.
>> Very easy to use efficiently for a human coder, though I do have to
>> check the book often to see if a particular instruction supports a
>> particular mode of access, yet just the kind of thing to seriously
>> complicate a compiler's life.
>>
>>> But I found the varients of 8051 I used were obsolete on more than
>>> one occassion causing problems. I'm still sourcing SAB80C517 at silly
>>> prices for example.
>>
>> I gather that Atmel has an AT89 line that includes an external bus and
>> so does SiLabs.  Not sure how either of these would score on not
>> obsoleting designs, though.
>>
>>> I first used the PIC for very low cost apps around 1990 and found
>>> that there was always an upgrade path which didn't obsolete my
>>> designs.
>>
>> Yes.  I've been using PICs since the late 1980's.. just around the
>> very month that Parallax entered the public fray.  Nobody likes the
>> bare-bones ALU design for the smaller-width instruction families --
>> it's design guts lay out on the floor, plain to see.  But Microchip
>> has maintained a very serious commitment to upgrade pathways over the
>> entire time I've been involved (just after they decided to move beyond
>> the "million unit rice cooker customer" days and place them into a
>> broader marketplace.  I couldn't have guessed then how strong that
>> commitment would be.  But they seem to well know what is important and
>> they have clearly (to me) worked very hard to _earn_ the respect they
>> have gained.  And it's been so on almost every good business front.
>>
>> One begins to realize after experiencing such a company's commitment
>> to their customers, if that realization isn't already at hand, just
>> how relatively unimportant an instruction set is to all these other
>> business factors.
>>
>>> Secondly Microchip always have product available.  I recall one rep
>>> trying to convert me to the ST6. Then he said ST are behind on
>>> production and delivery was 4-6 months.
>>
>> Well, Microchip has had their days with delays (the wait for the
>> 18F252 from using the 18C252 comes to mind) but they have tended to be
>> shorter than longer delays.
>>
>>> There are better micros than the PIC from an engineering perspective
>>> but they are hard to beat from a production view point.
>>
>> In all the time I've used them, they have consistently maintained a
>> solid professional use pathway that simply doesn't break.  I have old
>> tools that they no longer make (ProMate II) and yet they still support
>> it without question or quibble.  If I have so much as a flaky power
>> switch they want me to send it in and fire off a replacement with
>> shipping included for the "bad" one, so that I don't even miss a
>> single second of use.  Same for the modules that plug into it.  Their
>> tools are supported, decades it seems after they don't sell them
>> anymore.  That takes commitment on their part.
>>
>> I find wringing of hands over the instruction set to be relatively
>> badly placed.  There are a lot more important things to focus on and
>> on those areas Microchip has done a yeoman's service across the board.
>>
>> Obviously, I use other manufacturers too.  It's _very_ hard to find a
>> 1MHz 16-bit SAR ADC anywhere in Microchip's monolithic cpu fold, for
>> example.  But none of have compared quite as well on the business
>> issues over the years.
>>
>> Jon
>
>Also when looking for a long term investment in micros you may have to 
>consider the companies viability.

I will turn this question around on its head in a moment.  Your point
is made, but there is another view, too.

>Microchip are essentially the only micro manufacturer actually making monay 
>and doing quite well at present.

I place this at the feet of the quality of their business managers and
their clear recognition of the right priorities in forging lasting
business relationships.  I am sure that there are excellent technical
resources developing microcontroller products at all of the other
businesses.  Perhaps just as good as found at Microchip -- I simply
can't compare them because I'm not informed about it.  But I do know
how they operate their business model.  And I have been little other
than impressed with it.  So while I'm sure that poor technical quality
would kill them (so I'm sure they do have good technical resources),
so also would a poorly arranged set of priorities in their business
design.  And their competition, from my experience, do not come very
close, sad to say.  Almost to a company, though they differ in the
reasons why I think they hang themselves on some point or another.

>All the others are losing money 
>hand-over-first and some are in a very bad state.

I would tend to imagine this would give them a clue.  Standing on the
outside as a consumer of these kinds of products, I have no question
at all why Microchip is doing well.  It's actually pretty easy to see
why they are successful.  They are committed to a mutual relationship
in business and they actually _work_ at earning their respect, day in
and day out.  They just don't slip up on this.

If they do fail, it will only be because the entire field is in a nose
dive.  Not because they didn't get the business issues right.

>All the fanboys scream 
>Atmel, but they haven't made a cent since they started, and are probably the 
>most unstable in terms of long term viability.

I don't know much about Atmel.  I developed one commercial product
using their AT90S2312, I think.  From start to finish, it took me 4
days to write it and the experience was excellent during the process
because I never needed to actually call for any support from Atmel and
the part worked well.  Later, when considering an AT91 from Atmel's
French arm, experiences turned significantly sour because I did have
to involve them.  And that's the last time I considered using Atmel
for professional use -- I still like them for personal projects where
I know in advance I'm not depending on them for anything serious.

I tend to imagine that it is Atmel's own fault for ordering it's
business priorities wrongly.  At least that's a consistent theory from
my short experience with them.  I would have NO problem specifying an
Atmel part for some hobbyist project.  But that's about where I draw
the line.  And just perhaps, others have also learned from experiences
not unlike my own.  Perhaps they are paying the piper, now.  But I
can't say.  Might be for entirely different reasons.

Love your web site, when I get time to enjoy it!

Jon