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Serial in a USB world and what options do I have? — Parallax Forums

Serial in a USB world and what options do I have?

deadwhaledeadwhale Posts: 30
edited 2008-04-22 01:07 in Robotics
I'm guessing this has been beat to death, I did a search for this but didn't quite find what I what I need to know. I just got a serial boe bot (the price was right)
and have an all USB computer. I know I can buy the adapter from Parallax, but was wondering if a USB to serial cable from the local store will
work, or if a serial card in my computer will also solve the problem. In other words, is the serial to USB converter that Parallax has the only way to get my boe bot
connected to my computer? And if not the only way, is there a 'best' way?

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Comments

  • Mike GreenMike Green Posts: 23,101
    edited 2008-04-05 02:30
    A serial card in your computer can work or a variety of USB to serial converters can work. The crucial piece is that there has to be an implementation of several handshake lines (CTS, RTS, DTR, DSR) in addition to the data lines. The adapters sold by Parallax do this properly and those made by FTDI also work. Keyspan's High Speed USB Adapter works.
  • PJAllenPJAllen Banned Posts: 5,065
    edited 2008-04-05 02:31
    If you can place a serial card, do that.

    If you want to try a USB-to-serial cable other than Parallax's then determine beforehand·that it can do all of the hand-shaking·because not all of them·do so.· [noparse][[/noparse] Will someone at the store be able to say, definitively, "Yea, Yea" or "Nay, Nay"? ]· Mine is a Gold-X and it works.
  • Phil Pilgrim (PhiPi)Phil Pilgrim (PhiPi) Posts: 23,514
    edited 2008-04-05 02:32
    All things considered, your safest—and possibly least expensive—bet is the Parallax USB to serial converter. Although it's certainly possible that the converter you buy from your corner computer store will work without a hitch, not all of them have the handshaking line support necessary for compatibility with the BASIC Stamp.

    I prefer keeping my life simple and hassle-free. In that spirit, I'd pick the Parallax converter.

    -Phil
  • ercoerco Posts: 20,256
    edited 2008-04-06 05:34
    I've tried 2 USB-serial adapter cables and only one worked on the Parallax Stamps, so I'm batting .500 .· An $8 TRW-swapmeet Taiwan-made "Aten" brand (model UC-232A) worked perfectly, but my $6 ebay China-made "HL" brand didn't. Expect to install drivers from an enclosed CD. My OS is WinXP.

    Interestingly, I found this at ·http://en.wikipedia.org/wiki/Serial_port·:

    The vast majority of personal computer motherboards still have at least one serial port. However some may only have a pin header, and a fly lead is required to bring the connector out through the case. Small-form-factor systems and laptops, however, often do not include them in order to conserve space. RS-232 has been standard for so long that the circuits needed to control a serial port became very cheap and often exist on a single chip, sometimes also with circuitry for a parallel port.

    If that's true of your desktop's mobo, you could hack a serial cable and plug it on your mobo's connector.

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    ·"If you build it, they will come."
  • deadwhaledeadwhale Posts: 30
    edited 2008-04-06 17:51
    Ok...thanks for all the information from all of you. So, if it says 'RS-232' I can expect all the necessary handshakes and if it just says
    'serial' (this being a sometimes devious world where people will sell you almost anything) I might not???

    And one last question - if I hook up something that isn't quite compatible I can just expect it not to work, I shouldn't expect any damage to
    either device?

    Thanks again. You've all been a great help.

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  • allanlane5allanlane5 Posts: 3,815
    edited 2008-04-06 23:57
    1. Yes, if it doesn't work, it won't damage anything.

    2. If it says "Belkin", it probably won't work. If it says "PDA", it probably won't work. If it says "KEYSPAN" or "FTDI", it will definitely work. If you buy it from Parallax, it will definitely work, IF you load the USB to serial drivers properly.
  • deadwhaledeadwhale Posts: 30
    edited 2008-04-08 01:34
    Well, I picked up TWO USB to serial converts today, one from Radio Shack ($32 with the tax!) and one from a local bunch of guys trying to run a computer store
    (15.00). Neither store could tell me if they would or even should work.

    Neither did. I've already returned the RS one, the other I'll have to wait until tomorrow.

    What I get in the Basic Stamp Editor (v 2.1) is an 'invalid port' when I try to communicate with the BS2 with the identify procedure. I don't know if
    that's what normally happens, but I'm guessing it is. The program acts as though nothing was hooked up to the com port. It finds the port just fine, just
    doesn't manage to talk with it. It acts the same if I have the BS2 attached as it does if I don't.

    What is making me nervous though is I hooked all this up to an older Win 98 machine that I have just normally collecting dust that does have a serial port on it and got the same
    message (invalid port). I'm hoping that maybe it's just the batteries I have (though I've tried both 9 volt and the 4 pack AA's).

    So tomorrow after work I figure I'll see if the big computer store across the river will have serial cards and at the same time pick up some fresh batteries. Hopefully one or the
    other will get me started with this.

    After that, I guess it's order from Parallax, which I didn't want to do because I hate waiting for stuff to get here. But, I guess if this goes on much longer, the time involved, along with the
    trouble will pretty much be a wash, huh?

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  • Mike GreenMike Green Posts: 23,101
    edited 2008-04-08 04:37
    The current version of the Stamp Editor is 2.4 for Windows 2K/XP/Vista and 2.3.9 for Windows 98/ME/NT/2K/XP/Vista.
    'invalid port' seems like an odd message. Remember that the Stamp has to have power or it won't identify itself to the PC.
  • ercoerco Posts: 20,256
    edited 2008-04-08 05:07
    Your scenario does sound odd. Suggest you try connecting your BoeBot to a known working computer/cable combo and verify function.

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    ·"If you build it, they will come."
  • deadwhaledeadwhale Posts: 30
    edited 2008-04-11 04:20
    I couldn't find anyplace here in town that sold anything that people have told me works, and nobody in this area sells serial cards for computers, I think they'd rather
    sell cable adapters for USB to serial, so I've finally broken down and ordered the serial to USB adapter from Parallax. It's out of stock so I ordered the parts individually (they had that - both, just not
    bundled). Hopefully they'll give me the bundled price, but I don't think so...

    I'll download the latest version of the Stamp Editor and hook it all up and see what happens once my stuff gets here. With luck, that'll solve my problems.

    Thanks for your comments and help.

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  • deadwhaledeadwhale Posts: 30
    edited 2008-04-22 01:07
    Just thought I'd let you know that my problem is solved!
    I got the cable and USB adapter from Parallax today, downloaded the 2.4 version of the Stamp Editor
    and all the problems disappeared like magic!

    I didn't keep the 2.0 version on my machine, so I don't know if the problem was the cables or the programs.
    At this point I guess it doesn't matter too much until someone else bumps into the same problem. If that happens, I'll load the
    older version of the Stamp Editor back on just to see what happens. Until then, I'm a happy puppy.

    Thanks for your help and suggestions.

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