SX vs Prop

Ugha

Hi guys,

I've been recently toying with several BS2s in an attempt to learn
about microcontrollers... the only problem is the BS2 is a very
expensive device and I'm very reluctant to attempt to intergrate
it into more long-term projects.

I was looking at several other microcontrollers, AVR, PIC, ect and
I was somewhat overwelmed by all the options... so I decided that
my best bet was to stick with a company I know has good products
and has great service and assistance (through this forum). So I'm
sticking with Parallax products.

The only question is... which one?

I'm very pleased with the low prices on the SX, and especially by
the fact it can be programmed in C (a language I already know)
but the Prop seems be quite popular.

I'm aware that the Prop is more powerful, its capable of multi-tasking
and has a large database of functions available, but in a way that
kind of concerns me because my knowledge is very limited and the
Propeller seems to be more for advanced users.

On the other hand is the SX, WAY cheap to the point that its almost
disposible, programmed in C, seemingly simple. Yet nowhere near as
powerful/functional as the Prop. There also seems to be less info
on the SX than any other Parallax product besides the Javelin (which
is also too expensive for my tastes).

What would you guys recommend to a newbie in microcontrollers as
well as electronics?

My applications will include tinkering with robotics, PC interface projects
as well as more "useful" projects like timers, an alarm system and automatic
pet doors.

Mike Green

Ugha,
This question comes up over and over again, sometimes including the Stamps and sometimes including other processors
There's not a right answer. You kind of have to make a list of what's important to you ... you already have mentioned
pretty much everything. Complicating this is that, pretty soon there'll be a commercial C compiler for the Propeller.

The SX is, like most of the 8-bit microcontrollers around, an "odd bird". By this I mean that it has lots of idiosyncracies
in how memory gets address and where information is stored for different functions. It has some weird rules about how
interrupts work and what happens when you miss one. You just have to learn this stuff and it's different from "the next
microcontroller", whatever that may be.

The Propeller is bigger and more complicated in some ways, yet is more consistent and regular in other ways. It can do
things that are more complex or compute-intensive than the SX, but sometimes you can do tasks more easily on the SX.

If you stick with a single cog for your own programming and just use "canned" routines that might make use of other cogs
like the display routines, or the keyboard or mouse drivers or FullDuplexSerial or Servo32, the Propeller is actually easier than
the SX to use. The SX/B compiler is pretty good, but it's much more idiosyncratic than Spin (has a lot more special cases where
you have to know a lot about the insides of the SX and assembly language).

crgwbr

The SX is really cheap compared to the Prop and BS2,, and for those simple projects you listed, it would probable work fine. But, IMHO the SX, mainly because of the (lack of) documentation, is harder to learn than the Prop. It could just be me, but SPIN seems to be very easy to learn, maybe even easier than PBASIC.

regards,
Craig

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LoopyByteloose

Buy both for to learn a lot more. The SXj will teach you to create Virtual Peripherals and provide you with 2k or 4k of EE/Flash programing space. The Prop will allow you to learn video, but each COG has less than 512 bytes of programing space per COG.

With the SX, I strongly recommend Guenther's text. And with the Prop, I strongly recommend Andre LeMothe's Hydra text.

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Do you want a quickly operational black box solution or the knowledge included therein?······

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Ugha

Andre LeMothe? Isn't that the editor for the Premier Press Game Development Series?

I love those books [noparse]:)[/noparse]

I think I will end up buying them both... I had an idea with the prop (basicly a mini-game system inside an
old gameboy case) but I need to learn a lot more before i even get to the planning stage.

So I will get the SX first and use that to learn more than the Stamps can teach me.

Paul Baker

You should definitely pick up the Hydra, which is Andre Lamothe's (yes its the same guy) gaming system based on the Propeller. It comes with the book Kramer has recommended. While it's the most expensive development system we have, it's a development platform for having known working hardware (and supporting software), and when you create the actual product you simply copy the hardware blocks you need onto your own board for a cheaper production unit.

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Paul Baker
Propeller Applications Engineer

Parallax, Inc.

RobotWorkshop

Ugha said...

I'm aware that the Prop is more powerful, its capable of multi-tasking
and has a large database of functions available, but in a way that
kind of concerns me because my knowledge is very limited and the
Propeller seems to be more for advanced users.

On the other hand is the SX, WAY cheap to the point that its almost
disposible, programmed in C, seemingly simple. Yet nowhere near as
powerful/functional as the Prop. There also seems to be less info
on the SX than any other Parallax product besides the Javelin (which
is also too expensive for my tastes).

My applications will include tinkering with robotics, PC interface projects
as well as more "useful" projects like timers, an alarm system and automatic
pet doors.

It all depends upon what you want to do with your projects. The Propeller is
a great chip but for some projects the SX has a few advantages. I think some
of these advantages may be a factor in regards to some of the projects you've
mentioned. Below are a few advantages the SX has:

- Low cost. A lot less expensive than the Propeller
- Runs at 5V or 3.3v. Makes it easier to interface with 5V devices
- Fewer external components required. (Usually just a resonator for accurate serial timing)
- Faster start up time. There is a latency on the Prop where it has to read the contents of a
EEPROM before it can really start. The SX on the other hand has its code flashed onto an
internal EEPROM and is ready to go as soon as you power it up.
- Code protection. (If this is a concern the SX will let you protect your code)

As an example on how the SX can be used you can read some of the Nuts'N'Volts columns
that JonnyMac wrote or you can pickup the December 2007 issue of SERVO which has an
article where an SX28 chip is used as a translator to make a SpeakJet chip act and look
like an SC-01 speech chip.

The Propeller has it's own advantages and it all depends on what you want to accomplish.

For the moment I find that the SX series works great for intelligent peripherals and for
interfacing projects.

Ugha

Paul Baker: The Hydra looks cool, but I've written games for Windows, Linux and the Nintendo DS... The Hydra looks fun
but I wouldn't get much thrill out of it simply because I want to do more than program, I want to learn electronics and
create something useful to myself and others with my own two hands.

RobotWorkshop: It runs at 5v? That's a huge bonus for me. I wasn't even aware of that (Must have missed it on the spec
sheets). I've been digging around in Nuts and Volts for a while now searching for info, it's hard going. I wish there was
some way to search the pdfs. Thanks for the info though.


I think I've decided... its the SX for me. It seems to have all the bonuses of PICs (low cost, low external requirements,
extremely range of applications) and Stamps (Simple programming, Easy computer interface and most importantly...
it's a Parallax product!) combined.

I still hope to one day upgrade to the prop (or whatever comes next, I'd love to see a BS3).

Anyone know what the estimated life expectancy is for the SX? I know that the only reason that the Stamps are still
alive is because there are SO many of them out there (Mainly due to Stamps in Class I guess) but it looks like some
of the other parallax products have "died off" so to speak. At least in popularity (Javelin for example). I don't want
to spend the next year learning something only to find an "End of Life" tag next to its listings on the Parallax site.

Zoot

I wouldn't worry too much about end-of-life for the SX. While it is a "frozen" chip design, most of the Stamps use it as their core processor (pretty much anything except the vanilla BS2 has an SX as it's core). In addition many of Parallax's peripherals use an SX20 or SX28 as their on-board micro (e.g. the Ping). In other words, Parallax would be killing more than half of their own product line if they stopped producing the SX. Now if Parallax itself went out of business.....

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Mike Green

Parallax seems to make products available for as long as there's a demand for them. The BS1 is still being used in products like the EFX-TEK Prop-1. The BS2 is widely used as the heart of Parallax's microcontroller curriculum (Boe) and their basic robotics curriculum (BoeBot).

Brian218

Hi Ugha,

I like the SX alot, and am also getting hooked on the Prop.

If you haven't already ordered yet, the SX Tech toolkit Pro is on sale for $149 (you save $80.00)

http://www.parallax.com/Store/Microcontrollers/SXProgrammingKits/tabid/140/ProductID/347/List/1/Default.aspx?SortField=ProductName,ProductName

Also, in your original post, where you asking for an opinion on what you need to know about electronics?