[sdiy] Propeller chip from Parallax

[Adam Schabtach]

> Antti Huovilainen wrote:
> > Question is, how is the propeller any better than say an 
> ARM7? (which 
> > has free devtools, full featured C++ compiler, is fast and 
> does have 
> > hw multiply).
> 
> ...runs pretty damn fast, is available from literally 
> hundreds of vendors, costs less than $5 in some cases, comes 
> with a wide variety of integrated peripherals and is upward 
> compatible with advanced architectures that can handle things 
> like realtime video.
> 
> No argument here.

[Disclaimer: I'm quite far from being a microcontroller expert. I'm a
microcontroller dabbler.]

I've been looking at the Propeller docs and while it's an interesting chip
from a conceptual standpoint, and there are some attractive things about a
multi-core microcontroller in the sense of partitioning tasks onto separate
cores, the following things make me hesitate:

1) lack of integrated peripherals. Looks like you have to roll your own
UARTs, I2C, and SPI for instance. There is code available for doing so, but
there are also multiple versions of the code, complaints on the forum about
lack of documentation for said code, etc. It's just not as tidy as having
this stuff in well-documented silicon.

2) lots of ROM space and other resources devoted to video generation, which
seems to me is irrelevant for most applications other than building a game
console. 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. I don't even have a TV, for starters... Okay, so the resources
aren't wasted if I'm not using them, granted, but this odd emphasis on video
generation makes me wonder ever so slightly about the overall product, if
you catch my drift.

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.

4) no in-circuit debugging. I've really gotten used to being able to debug
my projects, at the source-code level, with the AVR tools and a JTAG
interface. I'd have a hard time giving that up. 

5) not much RAM. It probably has enough for many projects, but this also
seems to be a common issue on the forum.

Again these are just opinions formed after taking a look at the docs and
discussion forum. Take them with a large grain of salt.

--Adam