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Homebrew Serial comuinication wire — Parallax Forums

Homebrew Serial comuinication wire

Rob311Rob311 Posts: 83
edited 2006-07-09 20:29 in BASIC Stamp
Im building a carrier board for my bs2, and i need the wireing for a serial conection to my pc.
From what i see its pretty simple, grnd, tx (w/22k), rx.· Anyone out there with a nice pretty picture so i can assure myself that im not going to blow up my stamp when i go to program it? or even a discription of what to do?

Thanks much
~Rob

Comments

  • PJAllenPJAllen Banned Posts: 5,065
    edited 2006-07-09 03:27
    If you just need a cable, it's an extension (pin1 to pin1, pin2 to pin2,...), male to female.·· Pin 1, 8, 9 are not used.

    If you need a schematic of the interface circuit, see attached.
    pdf
    pdf
    supercarrierbd.pdf
    70K
  • Rob311Rob311 Posts: 83
    edited 2006-07-09 03:33
    O my.. that looks mighty complicated...
    As of right now i have to remove my bs2 from my application circuit board in order to put it into my USB board of ed carrier board so i can program it.
    I need to know what wires to connect from the back of my computer, at the serial port, to what pins on my bs2 so i dont have to use the UBS carrier board.
    That diagram is just way to complicated...
  • Beau SchwabeBeau Schwabe Posts: 6,557
    edited 2006-07-09 05:05
    Rob311,
    ·
    See if this is any better?.... It's actually the same thing Pj Allen posted, but stripped down to the bare programming cable essentials.
    ·
    If you solder the CAPS directly to the DB9 connector, you can use the standard flat grey 4-conductor telephone cable with a 4-pin
    SIP header on the other end.· I use this method to program a BS2·directly on a solderless bread board.
    ·
    ·


    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Beau Schwabe

    IC Layout Engineer
    Parallax, Inc.
    COM2BS2.JPG
    977 x 725 - 89K
  • Rob311Rob311 Posts: 83
    edited 2006-07-09 14:10
    Beau,

    Thats exactly what i need. But whats up with other people leaving out the capacitors and putting in a 22k resistor?

    btw, telephone cable, sip header, wonderfull idea!
  • LoopyBytelooseLoopyByteloose Posts: 12,537
    edited 2006-07-09 14:43
    If I recall correctly when you want the BS2 to receive only, the 22k resistor is doable on any of the 16I/O pins, but you have to reverse the transmit/receive logic in the SERIN and SEROUT commands.

    Beau is providing a complete programing interface which allows DEBUG to display info on the PC.

    This is one of TWO interface choices.
    This is IDE mode ONLY. Communications is through the PBasic IDE 'Debug Screen' and programming the Stamp is available.
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    The other is Hyperterminal Mode.· THIS REALLY MAY BE MORE THAN YOU WANTED TO KNOW AT THIS TIME.
    You can read all this is the PBasic Manual later.
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    The 22k resistor is the cheapest entry into the second choice.· You use SERIN to recieve and·SEROUT to transmit from the regular I/O pins Pins 5 through 20.· Hyperterminal would be your software AND you have to loopback the plug at the PC.· One 3 pins of the DBP male go to the Stamp - Pins 2,3, and Pin 5; Transmit, Recieve, and Signal Ground respectively.

    The male DB9 would have Pin 7 connected to Pin 8 [noparse][[/noparse]let us say Lookback A] and Pins 1,6,4,and 9 connected together [noparse][[/noparse]call it Looback B].·

    While the 22k resistor works, a Max232 chip is a better way to do this as you can use longer wire and higher speeds.

    ~~~~~~~~~~~~~~~~~~~
    As far as CABLES, you can you the same straight through cable with both and same a lot of hassle.

    In the first, you create your wiring on the Supercarrier board.

    In the second, you can make a male DB9 to female DB9 adapter that passes Pins 2,3, and 5 to the female DB9.·

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    "If you want more fiber, eat the package.· Not enough?· Eat the manual."········
    ···················· Tropical regards,····· G. Herzog [noparse][[/noparse]·黃鶴 ]·in Taiwan

    Post Edited (Kramer) : 7/9/2006 3:01:57 PM GMT
  • Rob311Rob311 Posts: 83
    edited 2006-07-09 20:01
    thank you eveyrone for your comments, one last question.
    The capacitors, do they have + and -? im using ceramic disk capacitors and there is no indication of annod or cathod....
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2006-07-09 20:15
    Hello,

    ·· Ceramic Disc Capacitors are non-polarized, so either way is the same.

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Chris Savage
    Parallax Tech Support
    csavage@parallax.com
  • Rob311Rob311 Posts: 83
    edited 2006-07-09 20:29
    Thanks much Chris
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