Parallax Propeller

I haven't heard anyone talking about the Propeller since earlier in the 
year when it had just been released so I'd like to share my impression 
of it with anyone who is interested. BTW, I have been heavily into 
LPC21xx ARM chips the last year or so and this is something completely 
different.

I received a Parallax Propeller eval board last week and I have been 
hooked on it since. At the moment I have my board outputting 128 chars x 
64 lines VGA text in color, outputting an independent TV text display in 
color, reading from an electret microphone directly (only Rs & Cs) and 
digitizing using internal sigma-delta into a buffer with delay and echo 
and spitting that out at the same time through another RC network 
straight into the monitors speakers. Meanwhile a PS/2 keyboard and a 
serial coms port as well as I2C is operating.

There are no glitches or hiccups, it just runs as smooth as, all this 
without external h/w support, I am impressed.

Sure, it doesn't have a 512K byte Flash, it loads it's software through 
the serial port or an external I2C EEPROM into it's 32K of main RAM 
which sounds a bit limited, but look what it can do with it! The 
Propeller is comprised of eight 32-bit processors each with it's own 2K 
byte RAM connected to a central hub with the 32K of main RAM and 32K 
ROM. You can find out more at http://www.parallax.com/propeller/index.asp

The price has just been halved by Parallax to promote volume use.

Parallax have an active forum running but has anyone else had experience 
with this chip?

*Peter*

Peter Jakacki wrote:
> I haven't heard anyone talking about the Propeller since earlier in the 
> year when it had just been released so I'd like to share my impression 
> of it with anyone who is interested. BTW, I have been heavily into 
> LPC21xx ARM chips the last year or so and this is something completely 
> different.
> 
> I received a Parallax Propeller eval board last week and I have been 
> hooked on it since. At the moment I have my board outputting 128 chars x 
> 64 lines VGA text in color, outputting an independent TV text display in 
> color, reading from an electret microphone directly (only Rs & Cs) and 
> digitizing using internal sigma-delta into a buffer with delay and echo 
> and spitting that out at the same time through another RC network 
> straight into the monitors speakers. Meanwhile a PS/2 keyboard and a 
> serial coms port as well as I2C is operating.
> 
> There are no glitches or hiccups, it just runs as smooth as, all this 
> without external h/w support, I am impressed.
> 
> Sure, it doesn't have a 512K byte Flash, it loads it's software through 
> the serial port or an external I2C EEPROM into it's 32K of main RAM 
> which sounds a bit limited, but look what it can do with it! The 
> Propeller is comprised of eight 32-bit processors each with it's own 2K 
> byte RAM connected to a central hub with the 32K of main RAM and 32K 
> ROM. You can find out more at http://www.parallax.com/propeller/index.asp
> 
> The price has just been halved by Parallax to promote volume use.
> 
> Parallax have an active forum running but has anyone else had experience 
> with this chip?

Hi Peter,
  Yes, the device is something different. Nice to see something fresh,
and I can see it would suit a class-room very well.
  (I also like the new Zilog ZNEO, as class-friendly, but it is not as
radical as the nifty propellor)

-jg

Peter Jakacki wrote:
> Sure, it doesn't have a 512K byte Flash, it loads it's software through
> the serial port or an external I2C EEPROM into it's 32K of main RAM
> which sounds a bit limited, but look what it can do with it! The
> Propeller is comprised of eight 32-bit processors each with it's own 2K
> byte RAM connected to a central hub with the 32K of main RAM and 32K
> ROM. You can find out more at http://www.parallax.com/propeller/index.asp
> 
> The price has just been halved by Parallax to promote volume use.

On the website it shows $25.00 for each chip, does that mean the price
is now $12.50?

I'm wondering what the target application would be for this. 32K isn't a
lot to work with for software, you'd have to struggle to fit an mp3 player
in that even if it's possible. mpeg-2 or -4 decoding...

I can see an approach where this device is a versatile helper processor
for the main cpu, which would have much more memory. The parallax
would be like handling the innermost loop in stuff. It would do its
functions
through bit banging in software say. DAC done with timer interrupt
outputting
samples at a steady rate. Video...I don't see how the chip could output a
stable video signal fast enough without additional support circuitry. A low
resolution 640x480 vga display requires a dot clock in the 25 mhz realm.

If you think of it as a low end programmable hardware type device then it
sort of makes sense, your software turnaround times will be much faster
than with FPGA development. Bandwidth in and out of the device will probably
be a limiting factor. The 32K RAM size...that's too small for the cpu
horsepower
there is it seems to me.

I just can't see a killer APP for it at its current price. If the price
were $5
possibilities could open up.

It sounds like a cool toy though. Alternative to the CEL architecture
and it's
available now. Programming both would be similiar I expect.

-Dave

-- 
David Ashley                http://www.xdr.com/dash
Embedded linux, device drivers, system architecture

David Ashley wrote:
> On the website it shows $25.00 for each chip, does that mean the price
> is now $12.50?

When I purchased this last week the distributor charged me half price 
because he said that Parallax had just cut the price. Both Parallax's 
and his website still show the old price but I guess the website 
designer is a little slow.

> 
> I'm wondering what the target application would be for this. 32K isn't a
> lot to work with for software, you'd have to struggle to fit an mp3 player
> in that even if it's possible. mpeg-2 or -4 decoding...

Hey, I can't see how I would do MP3 with the current chip either, but 
then again take a look at the Hydra at http://www.xgamestation.com/ to 
see what is being done with the Propeller, WOW!

> 
> I can see an approach where this device is a versatile helper processor
> for the main cpu, which would have much more memory. The parallax
> would be like handling the innermost loop in stuff. It would do its
> functions
> through bit banging in software say. DAC done with timer interrupt
> outputting
> samples at a steady rate. Video...I don't see how the chip could output a
> stable video signal fast enough without additional support circuitry. A low
> resolution 640x480 vga display requires a dot clock in the 25 mhz realm.

Yes, I can see this processor will "sometimes" be better off as a slave 
processor, it could replace what would have required an FPGA. Part of 
the power of the Propeller lies in the 2 dedicated counters and video 
registers per cog. It is possible to synthesis frequencies up to 128MHz 
as each counter has it's own PLL. Some guy even stuck a bit of wire out 
of one of the ports as a Q&D 49MHz RF transmitter for a toy.

There are no interrupts because you can devote a whole processor to a 
function but the DAC function is implemented by using a counter (1 of 
16) in delta modulation mode outputting at 40MHz so that only a simple 
RC filter is needed. The chip runs at 80MHz off a 5MHz crystal.

The same goes for ADC, although you could do sigma-delta with the cpu it 
is much easier to configure a counter for this.

The video registers can generate multiple 1024x768 VGA and/or TV video 
but it is up to a COG or two to process the frame data at this rate as 
there is very little RAM (at present).

> 
> If you think of it as a low end programmable hardware type device then it
> sort of makes sense, your software turnaround times will be much faster
> than with FPGA development. Bandwidth in and out of the device will probably
> be a limiting factor. The 32K RAM size...that's too small for the cpu
> horsepower
> there is it seems to me.

The 32K does seem a little small when compared to the memory sizes of 
many 32-bit embedded micros now. However this sounds just like the PC 
programmer who looks at these whiz-bang 32-bit micros and who used to 
100's of megabytes on the PC. You and I know you don't need that kind of 
memory but it sure is hard for the poor guy to get his head around it.

> 
> I just can't see a killer APP for it at its current price. If the price
> were $5
> possibilities could open up.

This chip is very new and I guess when they are selling volume they will 
be able to amortize their costs and also shift to a smaller process as 
their chips are 0.35um at present. Just think what it would mean if they 
shifted even to 0.18um.

> 
> It sounds like a cool toy though. Alternative to the CEL architecture
> and it's
> available now. Programming both would be similiar I expect.

Remember that this chip must be one of the very few that is even 
available in a 40-pin DIP pack which is what is required for those 
"great idea! let's try it out" moments. They also have QFP44 and QFN44 
packs.

Don't expect to use C to program this chip but the Parallax have 
developed their own language called "Spin". You can program a cog in 
assembler or Spin, here is a sample of Spin.

_____________________
PUB Toggle(Pin, Delay, Count)
{{Toggle Pin, Count times with Delay clock cycles in between.}}

   dira[Pin]~~                'Set I/O pin to output direction
   repeat Count
     !outa[Pin]               '  Toggle I/O Pin
     waitcnt(Delay + cnt)     '  Wait for Delay cycles
_____________________

Using the supplied Propeller tool (IDE) for software development is 
extremely simple, there is practically no learning curve. A tap of the 
F10 will see your code compiled and downloaded into the chip within the 
blink of an eye, well that's certainly how I found it.

I can't wait for when they do come out with Propeller II but until then 
there are plenty of applications that I am planning with the current chip.


*Peter*

I have just uploaded some of my recent screen shots of the Propeller 
running VGA and TV displays.

http://www.pbjtech.com/cpu/propeller/

*Peter*

Peter Jakacki wrote:
> I have just uploaded some of my recent screen shots of the Propeller
> running VGA and TV displays.
> 
> http://www.pbjtech.com/cpu/propeller/
> 
> *Peter*

Pictures look interesting. The graphics consist of lines in some cases.
Lines require memory. But this thing doesn't have enough memory
for the display. So how are the lines displayed?

I can imagine a system where you just have a display list, say a
list of lines to draw and a color for each. Then you have 2 small
strip buffers, and you clip all the lines to one of the buffers and
draw what would appear in that strip. Meanwhile you're displaying
the other. What a headache.

Every step of the game you're going to be butting up against the
hard 32K byte memory limit.

-Dave

-- 
David Ashley                http://www.xdr.com/dash
Embedded linux, device drivers, system architecture

"Peter Jakacki" <peterjak@tpg.com.au> wrote in message 
news:450e4d11$1@dnews.tpgi.com.au...
>I haven't heard anyone talking about the Propeller since earlier in the 
>year when it had just been released so I'd like to share my impression of 
>it with anyone who is interested. BTW, I have been heavily into LPC21xx ARM 
>chips the last year or so and this is something completely different.
>
> I received a Parallax Propeller eval board last week and I have been 
> hooked on it since. At the moment I have my board outputting 128 chars x 
> 64 lines VGA text in color, outputting an independent TV text display in 
> color, reading from an electret microphone directly (only Rs & Cs) and 
> digitizing using internal sigma-delta into a buffer with delay and echo 
> and spitting that out at the same time through another RC network straight 
> into the monitors speakers. Meanwhile a PS/2 keyboard and a serial coms 
> port as well as I2C is operating.
>
> There are no glitches or hiccups, it just runs as smooth as, all this 
> without external h/w support, I am impressed.

You have me intrigued. I have a project coming up that requires generating 
several HF signals count-locked to a 1kHz IRIG timing code, and this looks 
like a very interesting contender. Even if I decide to do it some other way, 
it's still a cute device. I shall read more. Thanks.

Steve
http://www.fivetrees.com 

Peter Jakacki wrote:
> I haven't heard anyone talking about the Propeller since earlier in the
> year when it had just been released so I'd like to share my impression
> of it with anyone who is interested. BTW, I have been heavily into
> LPC21xx ARM chips the last year or so and this is something completely
> different.
>
> I received a Parallax Propeller eval board last week and I have been
> hooked on it since. At the moment I have my board outputting 128 chars x
> 64 lines VGA text in color, outputting an independent TV text display in
> color, reading from an electret microphone directly (only Rs & Cs) and
> digitizing using internal sigma-delta into a buffer with delay and echo
> and spitting that out at the same time through another RC network
> straight into the monitors speakers. Meanwhile a PS/2 keyboard and a
> serial coms port as well as I2C is operating.
>
> There are no glitches or hiccups, it just runs as smooth as, all this
> without external h/w support, I am impressed.
>
> Sure, it doesn't have a 512K byte Flash, it loads it's software through
> the serial port or an external I2C EEPROM into it's 32K of main RAM
> which sounds a bit limited, but look what it can do with it! The
> Propeller is comprised of eight 32-bit processors each with it's own 2K
> byte RAM connected to a central hub with the 32K of main RAM and 32K
> ROM. You can find out more at http://www.parallax.com/propeller/index.asp
>
> The price has just been halved by Parallax to promote volume use.
>
> Parallax have an active forum running but has anyone else had experience
> with this chip?
>
> *Peter*

The chip looks nice to play with but @ $129 USD for a devkit it would
put a hole in my wallet. That SPIN language looks cool too! I am just
delving thru the datasheet to see how everything goes together.

-Isaac

Isaac Bosompem wrote:
> The chip looks nice to play with but @ $129 USD for a devkit it would
> put a hole in my wallet. That SPIN language looks cool too! I am just
> delving thru the datasheet to see how everything goes together.

My local distributor has the DIP40 + EEPROM + CRYSTAL for $24.20AUD. If 
you look at the demo board schematics you will see that is all you need 
other than a 3.3V supply and a bit of board to mount it all on. Use two 
pencell batteries and skip the regulator if you like. There is nothing 
that the demo board has that you can't do yourself with bits from the 
junk-box. The serial port can be a simple 2 transistor affair.

In fact I think the absolute bare minimum would be just the chip and a 
3V supply as you can boot this off the serial port and run it off it's 
internal oscillator.

*Peter*