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Help! my propeller won't spin! — Parallax Forums

Help! my propeller won't spin!

parts-man73parts-man73 Posts: 830
edited 2006-08-09 15:20 in Propeller 1
Well...I had time over the weekend to hook up my new propeller I got in the mail last week. I tried to "Identify hardware" and my computer can't find it.

I've soldered together the 3 transistor serial interface, I double checked that it matches the schmatic posted here perfectly. I checked with a multimeter to make sure I don't have any solderbridges. Everything appears correct.

On the breadbread side, I have just the basics. Just power and ground connected (on both side of the chip). The BOE is connected to ground. The reset from the transister interface board is connected to RES. and the 2 programming wires. I'm using a LM317 voltage regulator with a 240 and 390 ohm resistor. It's giving me 3.25 volts according to my digital multimeter.

I left out the crystal for now, I am assuming by looking at past posts from other users, that the propeller can run on it's internal oscillator. Is that correct to assume?

Is there any simple way to verify that the serial interface is operating? perhaps some LEDs, to see if there's any activity from the serial interface?

One other note - in the past I've had problems downloading to a different type of microcontroller, A PICAXE. The serial interface for those is just a few resisters. And my computer had a hard time connecting to the PICAXE chip too. Perhaps the serial port on my computer is not up to the task. I've heard of laptops having "low power" serial ports. This is not a laptop, but perhaps it has a non-standard serial port.

Any help would be greatly appreiated!
Brian

Comments

  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2006-06-19 15:45
    Brian,

    ·· If you bought a DIP Propeller Chip then there is no existing code on board to test the outputs.· You will need to establish communication to download something into RAM.· You mentioned having previous problems with this computer's communication...Do you have access to another to try?

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    Chris Savage
    Parallax Tech Support
    csavage@parallax.com
  • cgraceycgracey Posts: 14,206
    edited 2006-06-19 15:45
    Someone the other day had some transistor issues. These TO-92 transistors have varying pinouts. You might want to be exactly sure you've built what you've intended by verifying their pinouts.

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    Chip Gracey
    Parallax, Inc.
  • NewzedNewzed Posts: 2,503
    edited 2006-06-19 16:20
    Brian, I think you have to have the MAX3232 and the EEPROM installed for the PC to find the Propeller.

    Sid
  • parts-man73parts-man73 Posts: 830
    edited 2006-06-19 16:39
    I will try a different computer tonight.

    I am using the serial interface shown here...http://www.parallax.com/propeller/media.asp

    I thought I saw a simple transister interface at some point, but can't find it now.

    Brian
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2006-06-19 16:39
    Newzed said...
    Brian, I think you have to have the MAX3232 and the EEPROM installed for the PC to find the Propeller

    Sid,

    ·· EEPROM is not required, nor is the MAX232 if using the Transistor serial interface.

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    Chris Savage
    Parallax Tech Support
    csavage@parallax.com
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2006-06-19 16:42
    The transistor interface was shown in the following thread...Toward the end of the thread...Beau Schwabe posted it.

    http://forums.parallax.com/showthread.php?p=581230


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    Chris Savage
    Parallax Tech Support
    csavage@parallax.com
  • parts-man73parts-man73 Posts: 830
    edited 2006-06-19 17:02
    I found the one I was refering to... it's http://forums.parallax.com/forums/default.aspx?f=25&m=123910

    I'm gonna try to throw that one together tonight, on a solderless breadboard this time. And I'll let you know how I make out. I'll also try another computer.

    If all else fails, I'll be ordering a USB2SER on payday!

    Thanks for the fast responses!
    Brian
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2006-06-19 17:12
    Brian,

    ·· I haven't tested that interface myself...But I have tested the one I sent you the link to.· You could try that one first.· Take care.

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    Chris Savage
    Parallax Tech Support
    csavage@parallax.com
  • parts-man73parts-man73 Posts: 830
    edited 2006-06-19 23:24
    I'm spinning! I'm spinning!

    I used the simple 2 transistor interface. And it connected right away. I tried Blink.spin and I've got a flashing LED.

    I must've put the 3 transistor interface together wrong.

    Thank you again for your outpouring of support!
  • parts-man73parts-man73 Posts: 830
    edited 2006-06-20 12:51
    Ok, I got the 3 transistor interface working, I attached a picture of the finished product. I forgot the resistor between RX and DTR on the serial cable end of the circuit. Works great now.

    I built a 3.3 voltage regulator right on the board, with a polarized 2 pin header to take the regulated power down to the solderless breadboard. The serial interface is on the left side of the board.

    It all fit on the small board I got from radio shack, there were exactly enough traces on the board to make all the connections.

    Thanks again for all the help!
    100_0962.JPG
    2032 x 1524 - 830K
  • Beau SchwabeBeau Schwabe Posts: 6,568
    edited 2006-06-20 16:02
    parts-man73,

    I'm glad that you got both transistor versions up and running!!!

    Happy spinning!

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    Beau Schwabe

    IC Layout Engineer
    Parallax, Inc.
  • RinksCustomsRinksCustoms Posts: 531
    edited 2006-08-09 15:20
    i was trying to, ummm, "hack" a BS2OEM board for the serial interface to my new prop. It's a REV A1 board, the prop is the DIP40. Can you (with the interpeter chip unplugged) gain access to the onboard serial interface & eeprom socket like the schematics suggest? The interpreter socket pins; 8 - Sout, 9 - Sin, (6 - Sdata, and 7 - Sclk for the eeprom socket access)I have the propeller @ 3.3V & the OEM board running 5V from a 400W ATX power supply, so there's no insuf. power supply here! lol. I thought it might be nice to be able to access the onboard eeprom (16Kbits) for some small test prog's

    I'll try 'n construct the 2/3 transistor interfaces noted above in the mean time... Breadboarded the 3 transistor ver twice and it doesn't work @ 3.3V, i hope i don't have a dud, maybe if i make the adapter on a PCB like you guys it'll work, i just don't get why it won't work, i have it exactly hooked up like Beau's bare bones picture.

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    Definetly a E3 (Electronics Engineer Extrodinare!)
    "I laugh in the face of imposible,... not because i know it all, ... but because I don't know well enough!"

    Post Edited (RinksCustoms) : 8/10/2006 12:00:17 AM GMT
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