Microcontroller Shootout – Parallax Propeller

PropellerThe Parallax Propeller (P8X32A) is a 32bit microcontroller with a difference. It contains 8 cores (called cogs) and can run different routines simultaneously. The propeller doesn’t seem as popular in the UK as it does in the USA but that’s probably because there are only a few places that stock it and it’s more expensive that the Arduino. It’s a shame really because it really is a great little chip. One other thing that may have caused the lack of adoption was the fact that it had to be programmed in a language called SPIN. Over the past couple of years however, Parallax have listened to the masses and have now provided a C programming environment for use with the Propeller.

QuickstartHere at The Hack Shed we have four different Propeller based boards. The first one is the P8X32A quickstart board. This board is great to get going with. It’s a basic no-frills board with 40 IO pins available, 8 LEDs and 8 buttons. I really like the no-fills approach. Some of the other boards come complete with all sorts of devices onboard which can be a bit overwhelming to people just trying to start with the basics. This is the board I used to test my LED flashing code on.

BOEThe next Propeller board we have is the Parallax Board of Education (BoE). This uses the same chip as the quickstart but has plenty of peripherals included. While I love the quickstart, this is the board that really lets you show off the power of the propeller.

It comes included with a VGA port (yes the propeller does VGA out), a microphone, speaker output, microSD card slot, servo headers, 9v battery adapter and built in breadboard.

ChameleonThe third board we have is a strange one. Named the Chameleon-AVR, this board combines an Arduino board and a propeller board in one. It was designed by a guy named Andre LaMothe who has also developed several other development boards. To be honest, I got super excited when I heard about this board and paid a silly amount of money to get it shipped to the UK. When it arrived, I became totally stuck. I hadn’t used a Propeller before I ordered this board and found myself getting nowhere fast with it. While it did come with loads of documentation and example code, I still couldn’t figure it out. The website for the board was pretty much dead and I just lost interest in it. Now I’ve used the propeller a bit more, I do use this board more often, especially for running Jeff Ledger’s excellent PMC. The chameleon is interesting because as well as being able to use it as a dedicated Arduino or Propeller, you can write Arduino code which passes off other tasks to the Propeller chip to be processed. I’ve never done that though so I can’t say how well it works.

DEFCONThe final board we have is rather special and I can’t bring myself to use it. It’s actually a badge from the DEFCON 20 hackers convention. I won mine in a competition from Propeller Powered (Jeff Ledger’s site). The organizers of DEFON contacted Parallax and asked them to design an interactive, electronic badge. The attendees of DEFCON wore the badges which communicated with other badges via Infra-red. There was also a hacking challenge based on the badges. The badge contains the Propeller chip and all supporting circuitry to enable it to perform just the same as any other Propeller board.

Right then, on with the show. The first thing to do is head over to the Parallax website and download the tools. To be perfectly honest, I think Parallax could make it a little easier to find their download section. I’d quite like a big link on the homepage… but that’s just me.

propdev

Once you’ve found the link, download the file, extract the .ZIP file and then run the resulting installer file. The installation is nice and easy. The next step is to plug your board of choice into your PC and let Windows find the drivers for it (they were installed with the propeller tool). When Windows has finished faffing, you can run the program. You will be greeted with this screen. From here you can start coding or open one of the many examples included with the software.

spincodeThe IDE does a nice job of adding coloured blocks to your code which helps identify certain functions. Here is the example code to make an LED blink.

 

SPIN can seem a bit daunting at first but it really is quite easy to get the hang of. For anyone looking to get started with the propeller, I would highly recommend listening to the TymkrsFirst Spin” podcasts. They also do a series of “First C” podcasts now. Speaking of C, let’s show you the Parallax offerings for using C with the Propeller.

propcAnyone who’s used the Arduino before will have no problem adapting to the Propeller using C. ¬†While I haven’t used it much myself, I’ll probably switch to C for future projects. The IDE is nice and simple and self explanatory. While it doesn’t add the coloured blocks like the SPIN IDE does, it does colour the code in for you.

The screenshot on the left shows the code needed to flash an LED. It’s pretty self explanatory to any Arduino users. Parallax do have some material on their website about using C with the Propeller but I haven’t really had a proper look through it. One other thing to note is that Parallax provide development tools for both Windows and Linux.

propflashHere is a quick pic of our board flashing it’s LED. I know a picture doesn’t show it actually flashing so you’ll just have to trust us.

That’s pretty much it for the Propeller section of this shootout but we will be adding more complex features in future.

If you’d like to know anything else about the Propeller or have an idea of a project you’d like us to do, please get in touch. We’d love to hear from you.

 

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2 thoughts on “Microcontroller Shootout – Parallax Propeller

  1. Enjoyed the post :) It’s our favorite microcontroller for sure! One resource that folks might like is http://learn.parallax.com – it is an AMAZING resource for learning how to work with the Propeller. It gives coding examples, hardware wiring diagrams, and is my first resource for using peripherals with the Prop such as altimeters, gyroscopes, accelerometers, PIR, PING, and so much more.

  2. The Propeller is fantastic. It is extremely flexible – one minute it can be servicing four or more serial ports, the next VGA output. The independent cogs with shared RAM is genius and allows tasks to be distributed with no interrupts required!

    SPIN is quite logical and easy to use.

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