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Propeller Simple Spin Board — Parallax Forums

Propeller Simple Spin Board

HumanoidoHumanoido Posts: 5,770
edited 2013-07-20 21:11 in Robotics
Propeller Simple Spin Boardattachment.php?attachmentid=102746&d=1373597038
Propeller board minimal approach, assembles in 5 minutes, ideal beginner project

External Source
A simple design for a Propeller microntroller computer, the Propeller Simple Spin Board can be used to quickly write and test Spin programs.

ASSEMBLY
Assembles in 5 minutes using a solderless breadboard. This circuit is more simple than what's shown in the Parallax Propeller Education Kit. Parts include a Propeller chip and label, LED and hookup wire, two decoupling capacitors, and a couple AA batteries in a holder.

NO THIS AND NO THAT
The program is fed into the chip's RAM so no EEPROM is needed. The 5V LED runs on 3 volts and no dropping resistor is required. Software runs under RC Fast and RC enhancements so no crystal is needed. Batteries are used so no power supply components are needed.

THE BOARD
Stuff is mounted on one third of a Parallax breadboard from a Propeller Education Kit. Wiring is followed using the photo, no schematic needed.

EXTRAS
Extras include red and green colored stick pins for measuring at various points throughout the circuit. The simple battery holder has a lever action on/off switch.

MORE MINIMALISTIC
The circuit will run without the two capacitors. However, experts insist on using the decoupling components, so the caps are included in the circuit.

TEST PROGRAM
No project is complete without a test program. This simple Spin program will flash the LED on pin 15.
pub main
dira[15] :=1
repeat
 outa[15] :=1
  waitcnt(clkfreq/2 + cnt)
  outa[15] := 0
  waitcnt(clkfreq/2 + cnt)

PARTS LIST
01 - Propeller Chip P8x32a-d40
01 - Propeller Chip Printed Label
01 - Parallax Prop Plug
01 - 4 Pin Connector
01 - 5V Red LED
02 - .1 uf Decoupling Capacitor
02 - Stick Pin (Red & Green)
01 - Set of Jumper Wires
01 - Battery Holder with Switch
02 - AA Battery
1/3 Breadboard

attachment.php?attachmentid=102745&d=1373596646
Simple Spin Board Wiring Image - the yellow wire near P1 is for experimenting only and not needed

PROPELLER PARTS FROM PARALLAX
http://www.parallax.com/PropellerEducationKit/tabid/377/Default.aspx

Propeller Simple Spin Board Schematic
Go to post 11 to find a new schematic or click below.
http://forums.parallax.com/attachment.php?attachmentid=102795&d=1373878746
spin board wiring.jpg
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PROP BOARD.jpg
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Comments

  • TtailspinTtailspin Posts: 1,326
    edited 2013-07-11 21:34
    Does not get much simpler than that..:thumb:

    -Tommy
  • WBA ConsultingWBA Consulting Posts: 2,934
    edited 2013-07-11 22:59
    Simple and small is always the way to go!

    M44D40+_PowerTwig_PEKit_1.JPG

    M44D40+ and PowerTwig combo: Full Propeller circuit and 5v/3.3v supplies.
    M44D40+_PowerTwig_PEKit_1.JPG
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  • prof_brainoprof_braino Posts: 4,313
    edited 2013-07-12 07:32
    sorry, wrong thread!
  • HumanoidoHumanoido Posts: 5,770
    edited 2013-07-12 21:39
    A More Simple Program

    Here's a program with 5 statements instead of 7 to blink the LED on pin 15.

    attachment.php?attachmentid=102764&d=1373689568
    more simple blinker.jpg
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  • HumanoidoHumanoido Posts: 5,770
    edited 2013-07-14 06:34
    First Modification
    Disabling the Brownout Detector

    In this first modification to the Propeller Simple Spin Board, the connection from BOEn to Ground is removed. Insert a new connection between BOEn and Vdd. This will disable the brownout detector by connecting it to high, and prevent the board from resetting at 2.7 volts or less.

    The Propeller Simple Spin Board is capable of operations at voltages much lower than 3.3 or 2.7 volts and disabling the brownout detector BOEn will make this possible. This will allow longer battery operations as the voltage drops down. How low can you go below 2.7 volts? This is left as a student exercise.

    The new schematic reflects this change. (soon to be posted)

    For more information
    http://tymkrs.tumblr.com/post/11655486643/propeller-non-general-purpose-pins-explained
  • xanaduxanadu Posts: 3,347
    edited 2013-07-14 15:07
    The prop plug in your circuit works like that?

    Never mind, just looked more closely. Building a circuit off a pic is an exercise in itself!
  • xanaduxanadu Posts: 3,347
    edited 2013-07-14 15:52
    I can't seem to disable brown out detection, if I connect BOEn to Vdd even at 3.3v the Prop won't do anything. Otherwise I would try this.
  • HumanoidoHumanoido Posts: 5,770
    edited 2013-07-14 22:33
    xanadu wrote: »
    I can't seem to disable brown out detection, if I connect BOEn to Vdd even at 3.3v the Prop won't do anything.

    Put an external pullup on RST. When BOE Brown Out Enable is grounded, the Propeller chip has an internal pullup activated. When BOE is held high, the internal pullup is not active, and an external pullup is required on RST to restore functioning.
  • HumanoidoHumanoido Posts: 5,770
    edited 2013-07-14 22:41
    xanadu wrote: »
    The prop plug in your circuit works like that? Never mind, just looked more closely. Building a circuit off a pic is an exercise in itself!

    I'm working on a schematic that reflects the fundamental circuit and will post it when finished. I often use pics instead of schematics, especially when working with breadboards where everything is visible from the top. The first pic was a general project overview and only the second pic was intended to show wiring more clearly. A schematic was posted here.
  • HumanoidoHumanoido Posts: 5,770
    edited 2013-07-14 23:17
    Main schematic v1.1
    schem simple spin board.jpg
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  • Phil Pilgrim (PhiPi)Phil Pilgrim (PhiPi) Posts: 23,514
    edited 2013-07-14 23:22
    In your schematic, the LED is pointing the wrong direction. It also needs a series resistor for current limiting.

    -Phil
  • HumanoidoHumanoido Posts: 5,770
    edited 2013-07-14 23:56
    To disable the Brown Out Enable circuit and make programs still load, an additional resistor component is required. For the pullup circuit, I placed a 220 ohm resistor between RST and VDD. This is in addition to jumpering BOE to VDD.

    Testing was with the LED blinking program. After installing this circuit, I noticed when the Prop Plug was still connected to the computer and the USB port was still active, a tiny amount of power was being fed into the circuit. It was enough to continue running the program in memory even when the 3.0 volt supply was cut off. Switching the 3 volts on again resulted in the LED blinking becoming brightly visible again. However, with the mains off, disconnecting the USB resulted in power and program loss.
  • HumanoidoHumanoido Posts: 5,770
    edited 2013-07-15 02:06
    Phil: Thanks for proofreading. I appreciate this very much. The updated schematic is now in post 11.
  • xanaduxanadu Posts: 3,347
    edited 2013-07-15 08:47
    I normally accept nothing less than a perfect power supply, starting with "clean" house power. This was fun because I like pushing limits sometimes. It's not so bad to under power something (I'm assuming no permanent damage). In any case the Prop chip I'm using is so old and I have a few spares so...

    Thanks for the advice on the BO disable. Smells a lot better in here. I left out the resistor for the LED (LED is expendable as well) in an effort to minimize any extra power drain.

    RESULTS: I was able to lower the voltage to the point where the LED couldn't be seen 1.44 volts. I think I'll throw in a NPN and external power to see how low it really goes. I didn't realize a logic high/low could exist with such a small amount of voltage. Really cool experiment :)
  • Duane DegnDuane Degn Posts: 10,588
    edited 2013-07-15 09:00
    Xanadu,

    There was some discussion on the forum a while back about powering the Prop with lower voltages.
  • xanaduxanadu Posts: 3,347
    edited 2013-07-15 09:35
    Duane Degn wrote: »
    Xanadu,

    There was some discussion on the forum a while back about powering the Prop with lower voltages.

    Thanks! I missed that one. I'll check that next before bombarding this post with questions.

    I had to use a transistor to keep the LED going. After that:

    ~1.18v blink slows down
    ~1.0v P15 constantly high, no RAM loss
    ~0.5v P15 goes Low, no RAM loss
    <0.5v nothing and RAM loss

    >1.67v required to flash RAM

    *All voltages are approximate.

    IMG_1048.jpg
    IMG_1048.jpg
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  • HumanoidoHumanoido Posts: 5,770
    edited 2013-07-16 04:18
    Circuit without LED or Resistor
    xanadu wrote: »
    I left out the resistor for the LED (LED is expendable as well) in an effort to minimize any extra power drain.

    Great idea! One could simply run the PST Parallax Serial Terminal and a program to text "on...off...on...off... to emulate a blinking LED." The USB does not draw any power from the Propeller and this should allow lower power operations without the resistor or LED.
  • HumanoidoHumanoido Posts: 5,770
    edited 2013-07-16 04:24
    Lock & Load
    Retaining a Running Program

    I tried this simple experiment today. The circuit was loaded with the blinking LED program. The USB cable and the Parallax Spin Tool were completely removed from the board. The board continued to blink the LED and run the program. With a small UPS, the board can retain an operational program in Propeller RAM memory for the life of the power source.
  • xanaduxanadu Posts: 3,347
    edited 2013-07-16 11:42
    Haha the PST remind me of HAL dying, you can watch as the micro transmits its last bits. I like the idea of not having it attached to anything (in the long run). I was thinking of possibly building something low powered that wakes up on occasion and flashes an IR signal and seeing how long that runs on a supercap. Or something along those lines. Maybe a super cap and a small solar panel. It would be nice to make a small PCB for it, but we do need to figure out something for it to do to let us know it's working.
  • Duane DegnDuane Degn Posts: 10,588
    edited 2013-07-16 11:45
    Humanoido wrote: »
    One could simply run the PST Parallax Serial Terminal and a program to text "on...off...on...off... to emulate a blinking LED." The USB does not draw any power from the Propeller and this should allow lower power operations without the resistor or LED.

    Does the USB connection interfere with the low power experiments?

    Doesn't the Prop get some power from the Prop Plug?

    It might not be a good idea to have a USB connection during low power experiments.
  • xanaduxanadu Posts: 3,347
    edited 2013-07-16 12:18
    Also here is my setup for using external power if you want to add this in somewhere.

    external power.png


    R1 should be a low value, probably not a good idea to omit for long term projects
    R2 will need to changed based on the LED and power source, I used 1K 1/4w and 12v with a 2.3v LED @ 20ma (never did the math probably close enough for testing)
    L1 is the LED
    Q1 is a NPN, I used 2N2222
    external power.png
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  • xanaduxanadu Posts: 3,347
    edited 2013-07-16 12:29
    Duane Degn wrote: »
    Does the USB connection interfere with the low power experiments?

    Doesn't the Prop get some power from the Prop Plug?

    It might not be a good idea to have a USB connection during low power experiments.

    With a Prop Plug there probably isn't any power going into the circuit itself. I just tried re-doing it with the Prop Plug powered up and plugged in and achieved the same results. I think there are some boards that tap the USB power that don't use a Prop Plug.

    I left USB unplugged because I thought it might make my USB unstable or corrupt my IDE somehow. I hope to test that out today too. This isn't something that anyone should be doing unless it is with spare parts they don't mind parting with :)
  • HumanoidoHumanoido Posts: 5,770
    edited 2013-07-17 06:07
    Duane Degn wrote: »
    Doesn't the Prop get some power from the Prop Plug?

    Yes, described in post #13.
    Doing low power experiments require USB connection considerations or disconnect it.
  • HumanoidoHumanoido Posts: 5,770
    edited 2013-07-17 06:25
    xanadu wrote: »
    With a Prop Plug there probably isn't any power going into the circuit itself. I just tried re-doing it with the Prop Plug powered up and plugged in and achieved the same results. I think there are some boards that tap the USB power that don't use a Prop Plug.

    I left USB unplugged because I thought it might make my USB unstable or corrupt my IDE somehow. I hope to test that out today too. This isn't something that anyone should be doing unless it is with spare parts they don't mind parting with :)

    This is very interesting. In my circuit, disconnecting the 3 volt power but keeping the USB line active keeps the program running. When the lights in the room were dimmed, I could see the LED continuing to blink, though it was dim. This may have something to do with the LED choice and that it was not connected to a resistor.

    I've seen a lot of devices that tap into the USB port's 5-volt supply. I have a small desk fan that plugs into USB for power and two USB fans for the Big Brain.

    This test has no stability problems with Mac BST and running the Propeller circuit with USB connected. After the time to install Mac BST, install the correct driver, and get the font installed properly, it has worked great.
  • HumanoidoHumanoido Posts: 5,770
    edited 2013-07-18 05:12
    Serial Terminal Communications
    with the Propeller Simple Spin Board
    and "Non-crystalized Circuits"

    One question and the point of forum discussions has regarded serial communications with the Propeller running in RC modes without a crystal. Because the Propeller Simple Spin Board has no crystal and runs in RCFAST mode, a debugging solution is needed.

    The PST or Parallax Serial Terminal is a very good solution for PC endowed setups with "crystalized" Propeller circuits. In the case of the Propeller Simple Spin Board, we are using a Mac, BST, and no Propeller crystal. What is the solution to having a serial communications terminal up and running for input and output?

    It's confirmed that working with a Mac BST, the BST's Terminal, and a Propeller chip in RCFAST mode, serial communications can be established. Here are the settings:

    Propeller: no crystal, RCFAST default startup
    Software: BST, BST Terminal, PST, Terminal LED.spin, Parallax Serial Terminal.spin
    Settings: 1200 baud, 8-bits format, parity - none. The port is set to the Prop's port. Set Terminal Echo On to see the inputted values. Display ASCII.

    Startup: Set up the Terminal first. Establish settings. (Baud, Format, Port) Then go to Communicate , set Terminal Echo, Display ASCII, and Connect. Now Compile and Load RAM. General send/receive/format PST statements are working to make this a viable solution. A zipped demo is attached along with the PST object, and a view of the working system. The provided demo program is the version that runs the terminal LED only.
    zip
    zip
    TERMINAL DEMO.zip
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    Terminal LED View.jpg
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  • rjo__rjo__ Posts: 2,114
    edited 2013-07-20 21:11
    Humanoido,

    I love your posts. While every irritant doesn't lead to the formation of a pearl, every time I invest my time in following one of your threads, I am never sorry:)
    Many times, I learn something new, but even If I don't learn anything new, I at least get a nice warm feeling.

    Now that this project is a wrap... might I suggest that your Big Brain needs the Prop2...

    I'm wondering what the Big Brain will do with a new cortex... and improved eyes and ears.


    Rich
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