Parallax Propeller, why is it so overlooked?

RE: Parallax Propeller, why is it so overlooked?

mcb1 — Wed, 15 Mar 2017 04:39:10 GMT

12blocks is written by a guy here in Chch.

He's a guru for the Parallex stuff and the IDe will interface to a large number of different platforms (inc Arduino)

It's a drag and drop style but it does have the code albeit with unique names.

Why are you answering a 1yr old conversation???

RE: Parallax Propeller, why is it so overlooked?

macisonline — Wed, 15 Mar 2017 04:30:49 GMT

I have read that 12Blocks can help programming this chip. Have you try this IDE? Does it really have a good compiler?

RE: Parallax Propeller, why is it so overlooked?

rwgast — Mon, 02 Nov 2015 21:27:59 GMT

@DAB

Ya there is some neat things that can be done with it... I mean you have 16 counter that are independent hardware implementations, a 2MegaBaud UART and as I mentioned a scalable sigma delta ADC which is a speed vs resolution type of idea, this only requires careful layout and and passives. You can probably get a 20bit ADC with a dead bug layout if you dont want to design a mixed signal PCB for a manufacturing. I choose the propeller when I want pure determinism and speed, and do not mind laying out special peripheral chips as needed. Plop a cypress FX2 on the pcb and now you have 480Mbit USB, and a wiznet or ESP2886 and you have wifi. A few differential/instramention amps and bob is your uncle! Most of the time this works well because Im not going to wack a 24 bit dac on an atmega328. If determinism isnt very important and I can get buy with lack luster peripherals I will go with the AVR every time. I dont need a low noise hi res dac to display a battery voltage on a 16x2 lcd this is where AVR works great and it will drive a few relays to switch battery pack banks in and out with general purpose power to spare!

My personal system is for my robot has a few SRAM and i2C EEPROMs on board along with a propeller chip and an atmega 328 (acually two one 328 runs that battery system, 16 2400ah NiMH split into eight cells and eight 8 cells. One 8 cell set runs motors the other 8 cell set runs everything else, the idea was to get the motor transients isolated all the way back to one single ground point between systems, directly on the battery pack.) The idea of the 328 connected to the propeller chip has an a 4 line bus between the the two chips, with jumpers on each connection (this supports i2c,spi, or 4 bit parallel com bus). This is so I can use the 328 as a pin extender its function is to read all the sensors buffer the data in to its sram and then the propeller poles the AVRs stored values. The propeller is reading the quad encoders and running motor control chips. Then the rest of its cogs are there to do make calculations on the data and move the robot in the appropriate way. This bot will eventually have 2 custom made laser scanners (using wii mote cameras) and an SBC with a CAM running openCV. The SBC will crunch all the measurement data from the lasers and openCV then send that off to the propeller who will think about the right move to make combining the SBC data along with the 328's sonar and bump sensor data. Eventually SLAM will come to play, and maybe Parallela! But this is a clear case for the propeller. For those of you who haven't seen what it can do I figured Id post some unique things, that I dont think other micros can do very easily

http://forums.parallax.com/discussion/105674/hook-an-antenna-to-your-propeller-and-listen-to-the-radio-new-shortwave-pro…

http://forums.parallax.com/discussion/129652/the-lassiter-inexpensive-lidar-distance-detection-ranging-propeller-wiimote

http://forums.parallax.com/discussion/131954/my-attempt-at-23k256-sram-drivers-includes-8-bit-version

Triage Training System | learn.parallax.com

There is all kinds of stuff 6502, 780 emulators that are deterministic, projects running CP/M on the prop etc... these links kind of show the diversity, there are alot of industerial control and RF projects out there too

RE: Parallax Propeller, why is it so overlooked?

DAB — Mon, 02 Nov 2015 19:32:25 GMT

I took a look at the chip when it came out, but I was just not ready to move into a new computer system.

I always thought it had a lot of promise, but I did not have the time to look into how easily the eight processors could be exploited.

DAB

RE: Parallax Propeller, why is it so overlooked?

michaelkellett — Mon, 02 Nov 2015 18:11:26 GMT

Yep, that's what I meant when I said earlier that the XMOS has "special support logic" - it (and some other processors) are much better at bit banging than your normal micro.

Unfortunately the price that is paid for that (in the widest sense) has (so far) kept such processors out of the mainstream.

There's been a thread on E14 recently talking about the Snickerdoodle (I wish they had thought of a less silly name) which is an even cheaper way of getting a Zynq (but no array processor).

RE: Parallax Propeller, why is it so overlooked?

rwgast — Mon, 02 Nov 2015 17:18:58 GMT

michaelkellett the cool thing about a propeller or even an xmos is the abaility to bit bit bang protocalls out in 1 core/cog (im pretty sure you can get 20mhz spi in pasm) and still have room left over to do other tasks in that core.

I really have my eye on the paralella boards... with there zynq and the multi core they look awesome for sdr and other intensive applications. x

RE: Parallax Propeller, why is it so overlooked?

michaelkellett — Mon, 02 Nov 2015 15:52:08 GMT

For my work stuff I use mainly ARM based micros with FPGAs for the hardware gymnastics (when required).

I rather like the idea of all the esoteric chips but they've never looked convincing enough to actually use (Propellor, Parelella, XMOS, GreenArrays GA144 etc)

re. Joey's comment on I2C - I do often bit bang I2C on micros because I've had so much trouble with the built in stuff in the past. But it does mean that the micro is busy all the time it's I2C-ing.

RE: Parallax Propeller, why is it so overlooked?

crjeder — Mon, 02 Nov 2015 15:40:38 GMT

No problem with fan boys

I decided to go mainsteam (ARM) instead of niche (Xmos) despite I like the solutions in the niche products. PSoC and Xmos are very intresting (have dev boards lying aroud but no time to give them a closer look)

In the past I had an Inmos Transputer board which got me into programming but turned out to be not relevant on the market. Same with parallel programming, tile based rendering and many other technologies I had great hopes for. For hobby it is ok to look besides the mainstream, but if you have to make your living it's hard.

RE: Parallax Propeller, why is it so overlooked?

rwgast — Mon, 02 Nov 2015 15:09:18 GMT

The propeller can bitbang spi @ 10mhz+ and the Uart is 2Mbaud... It doesn't have USB and a lot of other cool peripherals but theHALre coming in the prop 2. I personally think using a dedicated chip works just as well. I think ARM has taken off, it has the Arduino IDE on some chips and EMBed.. I think it would be more popular if the chips were easier across to port HAL layers across vendors and cortex 0/1/2/3/4 architectures. I have plenty of ARM boards which wont run Embed.

I guess I think of the propeller as having 8 little arduinos in one chip with internal lines to talk to each other. There is no need for interupts on the propeller architecture, but if you must have them they have been implemented in software. The propeller also has 16 hardware based counters which are fairly useful, Ive been reading a piece of software that uses 3 counters to receive RF and mix the IQ signals and output audio. This is all done with just an inductor antenna and a few other passives to make the props sigma delta A to D work. Which btw is very scale able up to 16 bits (most likely higher if proper care is taken during layout), its a resolution vs speed trade off.

The chip is very capable It is niche but it's niche works very well for hobby robotics and automation. Its also much easier to program without interrupts the deterministic nature is great... you can count on things getting done in a certain amount of time without interrupts disturbing them. Im not trying to sound like a fan boy, I guess the real reason I wonder why the arduino took off over the propeller is because Parallax already had the hobby market with the basic stamp, so why did hobbyist pick a 16mhz single core mcu over an 80mhz 8 core mcu? I personally think the PSOC chips are great and wish they actually had the arduino market they are easy to use and the digital fabric allows you to get your feet wet with an HDL when your ready, on top of being an ARM core.

RE: Parallax Propeller, why is it so overlooked?

screamingtiger — Mon, 02 Nov 2015 14:47:08 GMT

Don't forget if it is implemented in software, it can conflict with resources since it will usually use one or more of the built in timers, ISRs etc..

RE: Parallax Propeller, why is it so overlooked?

crjeder — Mon, 02 Nov 2015 14:18:12 GMT

Anything in hardware is going to be 1000 times faster than in software.

True. But I2C standard speed of 100 kHz vs. 180 MHz uC? I guess software is good enough. Not all uC are used for "demanding" applications. Most are sleeping all the time wating for a key press from the user. (coffee machine, electric tooth brush...). But I wolud not use a 16 MHz M0 to drive the motors of a segway...

RE: Parallax Propeller, why is it so overlooked?

crjeder — Mon, 02 Nov 2015 13:57:22 GMT

Hmmm. I have to admit that I have not bitbanged a SPI signal but a WS2812. Timing tolerances are normally high enough to simplify the code. In case of the SPI slave I'd asume the masters and slaves clock to be accurate enough to not drift significantly. Then it's enough to have a interupt every SPI clock cycle to sample the input since it is not important to detect the edges only a "hig" or a "low" bit. Or do I overlook something here?

Thanks for your patience!

RE: Parallax Propeller, why is it so overlooked?

screamingtiger — Mon, 02 Nov 2015 13:48:32 GMT

Anything in hardware is going to be 1000 times faster than in software. However if implemented in software you can fix bugs, update standards etc...

One locked into hardware its written in stone.

The Pic32 has a bug in the I2C that cannot be fixed.

RE: Parallax Propeller, why is it so overlooked?

michaelkellett — Mon, 02 Nov 2015 13:44:15 GMT

Doing bit bang SPI in software absolutely cripples processor performance - especially when operating as a slave. You need to be watching for clock edges all the time which you can do with an edge detector peripheral and interrupts or by sitting in a loop. One way the processor gets loads of interrupts (at least one for every SPI clock edge) and the other it's 100% dedicated to the task. XMOS get round these issues by having multiple cores and some special support logic. A normal single core processor could not handle SPI at anything like the half or quarter of core clock speed offered by many SPI peripherals.

Modern processors often go one step further than just an SPI peripheral and use DMA as well so not only does the uP core not need to know about clock edges but it need not know or care about exactly when each byte is transferred.

(I've said SPI but applies to other interfaces as well.)

RE: Parallax Propeller, why is it so overlooked?

crjeder — Mon, 02 Nov 2015 13:28:52 GMT

IMHO there should not be any difference, SPI et al are slow compared to the processor speed and not very time critical. So a software implementation is not harmful to the performance. I doubt that this is the reason for software peripheral not being adopted widely.

A chip manufacturer probably asks: "What do I gain by dropping the hardware implementation of serial peripheral?" Because they already have implemented them in hardware the answer would probably be "Not much!"

I. E. it does not free significant chip surface. That's why I think they simply stick with hardware implementations. But if you design a completely new chip, you may think about it - as xmos did. Maybe that saved them the whole IO remapping / multiplexing and made the whole design simpler. (but I am again guessing here, I am not a chip designer).

RE: Parallax Propeller, why is it so overlooked?

michaelkellett — Mon, 02 Nov 2015 12:56:02 GMT

I'm not quite sure what you are getting at re. peripherals - are you saying that SPI, UART etc are better off in hardware or software ?

RE: Parallax Propeller, why is it so overlooked?

crjeder — Mon, 02 Nov 2015 12:02:29 GMT

So right now I can buy an ARM Cortex with a 180MHz clock 1Mbyte Flash, >192kBytes RAM, on chip USB, Ethernet, Encryption/Decryption etc etc for about the same price - the Propeller just doesn't offer anything expect less stuff and more hassle.

.. and run a propeller emulation on it with 1:1 speed (probably - I am guessing here)

Several companies have attempted to dump peripherals and code them all in software - it's never popular because it's hard work and difficult to support in practice and always gives worse performance than dedicated peripheral functions.

Performance should not be an issue, at least not for statdard perpiphals (SPI, PWM, UART, I2C ...) those are all simple protocols. Indeed simple enough to implement them whith a few gates in hardware... that's how they were designed.

RE: Parallax Propeller, why is it so overlooked?

crjeder — Mon, 02 Nov 2015 11:59:17 GMT

.. so why arduino?

Good question, IMHO. Why Propeller? Why anything else than ARM?

There is the market, you know.

I have seen so many brilliant designs die, despite them beeing much better as the dominant technology. Why everybody uses Intel CPUs not Sparc or Mips? Why has everybody nVidia graphic chips not BitBoys? (does anybody remember them?) Part of the answer is that improvements on the dominant technology is much quicker than the developement on a budget in a niche. BitBoys and Inmos Transputers for instance shared the same fate: their development cycle where so long that when their product finally hit the market nVidia / Intel respectively reached the same performance level in the meantime. So why switch? Consequently nobody did. Therefore they (BitBoys and Inmos) had no money the stay in the race.

An other thing is that parallel programming never took of. The only widespread thing is multi tasking / multi threading i. e. running many INDEPENDENT programs in parallel. But who uses 100+ cores to solve a single problem? This is still the domain of science, not consumer grade.

So the real question is: Propeller, why is it still around? They must have found a niche which pays them enough to survive.

Just my 2ct...

RE: Parallax Propeller, why is it so overlooked?

gdstew — Mon, 31 Aug 2015 13:22:18 GMT

The Freescale i.MX 6 SoloX has an ARM Cortex-A9 processor for running the "OS" applications as well as an ARM Cortex-M4 for running real-time processes.

The UDOO Neo board uses this processor.

RE: Parallax Propeller, why is it so overlooked?

michaelkellett — Mon, 31 Aug 2015 07:42:28 GMT

The Propeller chip is unpopular for so may reasons: it is very limited compared with ARM Cortex and far from cheap.

The 8 processor model is difficult to design with and this puts people off but there are worse features to come - each processor has a very limited amount of memory (512 words is tiny) and access to a bigger common memory (still only a tiny 8k words) is time sliced and so very slow. The next big issue is that the chip has effectively no on-chip peripherals. A typical cheap ARM Cortex will have SPI, I2C, UARTS, timers, USB etc etc.

Several companies have attempted to dump peripherals and code them all in software - it's never popular because it's hard work and difficult to support in practice and always gives worse performance than dedicated peripheral functions. XMOS are currently plowing this furrow and have found a few niche applications but aren't breaking into the mainstream (they've inherited too much attitude from Inmos so I don't think they ever will make the big time.)

So while the Propeller is interesting, and can give good performance if you get a job that is a really good fit, it isn't a patch on general purpose micros for general purpose jobs - and they make up most of the market. For niche stuff DSPs are much better at DSP, FPGAs are much better at massively // and can be clocked so much faster etc etc.

So right now I can buy an ARM Cortex with a 180MHz clock 1Mbyte Flash, >192kBytes RAM, on chip USB, Ethernet, Encryption/Decryption etc etc for about the same price - the Propeller just doesn't offer anything expect less stuff and more hassle.

RE: Parallax Propeller, why is it so overlooked?

rwgast — Mon, 31 Aug 2015 05:10:02 GMT

clemm are you talking about something like Zynq?

Ok so lets take this down to the hobbyist level Parallax has been around forever and they offer all there learning material FREE!! I am an electrician who wanted to learn electronics so I bought a friendly prop dip chip RTFM and stuck it on a bread board with some digi key parts and it worked. Next I soldered it to RatShack prefboard and added ps/2 vga and SD connectors! I mean 8 cores this sounded cool and I could use it to start learning electronics!

Parallax has some boards like the quick start which are as much as an Uno, so why arduino? Why not an 8 core mcu thats backed buy a company thats made basic stamps since the 90s? SPIN shouldnt even be the issue here since it has constructs of languages like basic/python which is much easier for a coder that doesnt know C, like most Arduinoists...

I am really in to SDR right now and there are examples of using the props counters only to make an AM receiver, so I can imagine the power of xmos! But what Im really in to is for an awesome SDR is the new Parallela board with the arm cpu and the 16 cores+fpga. Im trying to make the PsoC line my new chip for smaller projects that don't need parallelism over the AVR or another ARM core. I mean I can replace some complete boards with a PSoC5.... great for small test tools!

Got a little off topic though why Arduino and not the propeller? Obviously Xmos is more powerfull but not hobbyist friendly or should I say newbie friendly. BTW I got in to uC's 5 years ago and at that time it was kind of like the prop basic stamp or arduino and the prop had more power than an atmeaga and was just as easy to work with software/custom hardware side.

Off topic can someone tell me how to mark a response helpfull??!

RE: Parallax Propeller, why is it so overlooked?

clem57 — Mon, 31 Aug 2015 04:41:19 GMT

I am seeing more hybrids like a a9 with a fpga mixing full CPU with MCU like bare metal.

RE: Parallax Propeller, why is it so overlooked?

rwgast — Mon, 31 Aug 2015 04:35:43 GMT

Are there multi core arm mcu's? Like the cortex line? I know that there is an NXP with an m0 and m4 or something but other than that im talking mcu, not full fledged cpu.

RE: Parallax Propeller, why is it so overlooked?

shabaz — Mon, 31 Aug 2015 04:33:51 GMT

Given there will be a learning curve with any device, if I had to choose between the two, based on current information I'd pick XMOS because the development environment has a C compiler, the process synchronisation is POSIX-like so familiar to software developers, the development boards are cheaper ($12.50, and is raspberry-pi compatible), the parts are more powerful and faster, and there is recent silicon so that provides roadmap assurance. XMOS is used in commercial designs, for example a lot of high-end audio devices use XMOS.

Not knocking Parallax Propeller, I don't know it well enough and I'm sure it must be in commercial designs too to keep Parallax in business, and it does look like an interesting part but XMOS are more interesting to me.

RE: Parallax Propeller, why is it so overlooked?

screamingtiger — Mon, 31 Aug 2015 04:31:24 GMT

Im not sure what the issue is, but not having a compiler as well as flaunting a new , much more powerful version doesn't help. THough they have yet to release it and its been like 4 years at least!

Arm has multiple cores and is used in video game machines. Just much more visibility and much more market share. They've been around forever. Using a Prop would be a risk.