[sdiy] Propeller chip from Parallax

[phillip m gallo]

Agree with all said so far +/- Propeller.

But regarding:

"... I've really never thought "gee, this project would be so much
cooler if I could plug it into my TV" when designing, say, a MIDI/CV
converter.  ..."

here's a link demonstrating we must agree to disagree on this:

http://www.sdiy.org/philgallo/tvtadsrx.jpg

Also the Sine Table isn't a bad idea.

In it's current incarnation it's clear the Propeller is not going to Mars to
rove around.

It's a funny little microcontroller, specifically laid bare to allow simple
concurrency with deterministic results.  An ARM is a general purpose micro
with a multi-vendor eye to the latest requirements for power and periph's.
They aren't equivalent but the Propeller is well thought out in spite of the
excess of back-patting the site reflects.

I couldn't imagine doing more than boot loading with SPIN for delivery code
but imagine i'd test just about every feature and approach with it.  If you
stay in Assembler with the Propeller you'll use that tiny 512 code space per
cog for what it's worth.  The instruction set is ok not complicated or
especially dense.

regards,
p


-----Original Message-----
From: owner-synth-diy at dropmix.xs4all.nl
[mailto:owner-synth-diy at dropmix.xs4all.nl]On Behalf Of Batz Goodfortune
Sent: Friday, March 16, 2007 4:03 AM
To: synth-diy at dropmix.xs4all.nl
Subject: RE: [sdiy] Propeller chip from Parallax


Y-ellow Adam 'n' all.

At 10:35 PM 3/15/07 -0600, Adam Schabtach wrote:

>3) no C/C++. The SPIN language doesn't look altogether bad at first glance,
>and I understand the benefits of a language designed around the hardware,
>but I'd really rather work with a language I already know well. I'd rather
>not get partway into a coding effort and discover that there's something
>about the language that drives me bats.

I'm already Batz so I'm guessing it wouldn't be a problem. :)

I agree with most of this except the stuff about "C". I can't program in
high level languages for shit so I'm kinda glad they didn't lock it down to
something as archaic as C. One of the main reasons I can't get into bloody
AVRs is because every damn example I need to look at is written in C. Call
me old school but I'm use to actually optimizing my code. Trying to think
ahead as I write it.

(Hey if Harry can hate BBDs and breadboards, I can hate C.)

At first glance I love this thing. It's like. "Hey Baby, where you been all
my life?" On the other hand. "Oh yeah. Another freakin' micro to waste my
time and money on?"

And lest we forget that the afore mentioned ARM started life in exactly the
same way. In fact I felt exactly the same about that when it first landed.
When the "A" stood for "Acorn"

I don't believe you can really mention this and a transputer in the same
sentence. Well except for that last one of course. On the plus side, at the
time, a 10meg serial interconnecting, massively parallel network was almost
too good to be true. By the time it was released it was a bit ho-hum. But
the real drawback was that developing a transputer system was almost as
expensive as a serious coke habit and didn't make you feel like you were in
any way important. Prior to their release, Inmos boasted that the name
"Transputer" was an amalgam of "Transistor" and "Computer." (Yeah no shit)
But the philosophy was that it would be a small, powerful computing device
and used ubiquitously and as cheaply as a lowly transistor would be.
Bollocks! A base level transputer devel board was around the 2 grand mark
when it came out.

In short, the transputer never lived up to it's claims or even it's own
potential. I shudder every time I think of programming in OCAM.

The ARM. Now there was a processor. Those Acorn guys developed it within
about  8 months starting from scratch. They had a simple idea. Everything
should come in 32s. Make it 32bits wide. Make every register as good as any
other register. Let the damn developer decide how she's going to use it.
They stripped out all the crap and it ran blindingly fast. As testament to
the somewhat open and flexible design, they are the embedded weapon of
choice these days. Not just going strong but totally wiping the floor.

The thing that struck me about reading the blurb on the Parallax site is
that these guys were waxing lyrical about their achievement in the same
tones that the acorn crowed were when the ARM first hit town. What Acorn
did was considered equally unbelievable at the time.

As to architectural issues. In this case I see no real problem wasting one
of the cores doing menial tasks in leu of having dedicated hardware. Some
of us have been having to do that kind of thing for years anyway. Then
there's the example of the cypress PsoC. Another processor I've been
banging my head against. In concept it's brilliant. You have a blindingly
fast 8 bit core coupled with programmable logic blocks. So instead of
having dedicated I/O structures, you just build what you need. The usage of
the programmable logic depends on how complex your I/O tasks actually are.

I don't know which approach is better in any given situation but it seems
to me that devoting a core or 2 just to handle I/O amounts to roughly the
same thing.

What does seem at odds here is that they wax lyrical about how they hand
optimized the thing at damn near the molecular level and then jack it up
with a modularized, inefficient programming language. Which is anathema to
their original design philosophy. Not that I have a problem with this
exactly and this is the kind of thing Parallax are known for, but it just
seems a bit strange.

On the other hand, it also occurred to me that this may in fact be a rather
brilliant philosophy in the long run. Think about it. You pluck your new
baby animal fresh out of the zoo and you're not sure about the intricacies
of care and feeding. But you can throw a few quick bricks together and get
something happening. You can then tinker from there all the way back down
to the metal at your leisure. All the time knowing that you've got a base
level functioning system. This is how most of us old school bit bolters got
into the game in the first place. We started with some 8 bit machine. A z80
platform, maybe an apple ][. And then we started to explore it.

My original machine was a z80 based thing called a Microbee. The usual sort
of thing where you had BASIC in ROM and it doubled as the BIOS. But I knew
where all the back doors were so I use to confound my fellow Bee-keepers by
being able to task switch between several running programs at once.
Something I didn't see again till I met my first Apple Mac. So I'm thinking
here that what they have achieved is an easy way of elbowing your way into
the things. And that can only be a good thing IMHO.

As for price. These things are as cheap, if not cheaper than your average
AVR.   And on the face of it, seem to offer a lot more bang for buck. It
remains to be seen of course but it does seems there is something of a
trade off here. You don't get all that lovely I/O choice or on-board
resources of the AVR. And you don't get the specialized versions for music
and portable devices that you do with the ARM. On the other hand, I've been
banging my head against AVRs, PsoCs and ARMs for the past 2 years and
getting precisely nowhere. The development systems have cost me an arm and
a leg. Everything seems to be designed to keep you at arm's length from
what's really going on. Unless you're a recent graduate from computing
school or something. (Maybe) The reality is that there's a huge investment
involved in time and tools for these things and it gets worse if you want a
fast track. And I can tell you right now I'm sick of having to buy new
device programmers every time fucking ATMEL change their underpants.

Let me make this clear for the record. All of these processors are pretty
good. And I'd hate to have to go back to the days of running a 6502 at
1meg. FLASH is da' bomb! But I use to be able to afford the time and tools
to tinker. Most of this stuff has become a fucking millstone and I'd be
ever so grateful if this Propeller thing could save my bacon.

<sound=thunder>
The Batzman has spoken.
</sound>

They're going to wheel me back to my cell now.

Be absolutely Icebox.

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