🚀 go-pugleaf

On Oct 30, 2:09 pm, Jon Kirwan <j...@infinitefactors.org> wrote:
[.. was PIC now 8051s ..]
>
> I'm using one from SiLabs, right now.

Just one?  One of my designs is about to go into production with two
F120s
clocked at nearly 90MHz.  One of them is just about fully busy.  The
other
has many microseconds to spare.


> 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.

Do you really need true floating point?  do you really need ln() or
would log2() do?  18 microseconds seems a little slow.

Doing log2() of a 32 bit floater can be fairly quick if you don't
care
much about how much code space you use.

>  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.

Real men code in assembly anyway.

>
> >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