Converting DB-9 port to USB port

Discussion in 'Embedded Systems and Microcontrollers' started by CrackJack, Sep 27, 2010.

  1. CrackJack

    Thread Starter Active Member

    Aug 7, 2009
    127
    0
    Hello Everyone,
    I have this MCU which has a DB-9 terminal... I would like to
    change that DB-9 to a USB port, what all changes would I need to
    go through?

    Should I just connect a 47Ω resistor in series with the Tx and Rx ports of the RS-232???
     
  2. bertus

    Administrator

    Apr 5, 2008
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  3. CrackJack

    Thread Starter Active Member

    Aug 7, 2009
    127
    0

    Sir, thank you very much for the answer, I know about the cable, but I
    want to avoid cables... all i need is simply a USB port hooked on the output of the MCU, so that user can put in his memory stick and gather data... rather than connecting through a DB-9 port...
     
  4. bertus

    Administrator

    Apr 5, 2008
    15,648
    2,347
    Hello,

    If you want to connect a usb memory stick to the MCU, the MCU needs to be a host for USB.
    That will take probably an other MCU than you are using now.
    Read about USB in the links on the page I provided.

    Bertus
     
  5. CrackJack

    Thread Starter Active Member

    Aug 7, 2009
    127
    0
    hmm... alrite, thats what i thought so, isnt there a simple way apart from this???
     
  6. CrackJack

    Thread Starter Active Member

    Aug 7, 2009
    127
    0
    Hello everyone,
    I was doing some research on the available chips that can be used for rs-232 to USB conversion as it would be a matter of everyones concern to use such a chip... and i found some links..

    Please go through it and let me know if these chips can be used with min coding to convert from UART - USB
    http://www.silabs.com/products/interface/usbtouart/Pages/default.aspx#Matrix
    http://focus.ti.com/lit/ds/symlink/tusb3410.pdf
    http://www.futurlec.com/RS232_Converter.shtml
    http://www.linxtechnologies.com/Documents/SDM-USB-QS_Data_Guide.pdf
     
  7. Markd77

    Senior Member

    Sep 7, 2009
    2,803
    594
    These chips won't help. They are just so you can plug something that is RS232 into an USB socket. The computer and a driver sees the external system much as a normal serial port. The data is still in the RS232 format, it has just gone via the USB protocol and back.
     
  8. CrackJack

    Thread Starter Active Member

    Aug 7, 2009
    127
    0
    well, basically I would like a user to gather data from a USB port instead of a RS-232 terminal...

    There is no intelligence required at the USB level.. It would only be used as a mode of gathering data in a Data Acquisition System..

    Will it not work in such kind of application?
     
  9. Markd77

    Senior Member

    Sep 7, 2009
    2,803
    594
    I think the first, 3rd and 4th links would be suitable for that. They won't let you plug a memory stick into the microcontroller, but will allow direct PC-microcontroller communication.
     
  10. sceadwian

    New Member

    Jun 1, 2009
    499
    37
    CrackJack, USB REQUIRES intelligence, it's not a simple protocol there is no quick and easy hack you can do to make it compatible.

    A USB to RS232 adapter can be had for 10-20 dollars. You will find nothing cheaper than that home made or not.
     
  11. maxpower097

    Well-Known Member

    Feb 20, 2009
    795
    388
    I got some extra USB2Serial adaptors I'm selling off for $3 shipped in the US. I've sold a couple already so I'm sure you can find others to tell you its a good deal. They are made by Cables 2 Go
    These
    http://www.google.com/products/cata...WvOKLWxQXSo42kBw&sa=title&ved=0CDEQ8wIwAzgA#p
    There NIB too with antistatic bag and CD. That goes for any members too. I just want $1 + shipping INTL too so if you out of the country just let me know and if you pay the shipping I'll send it. I sent one to retched so he can vouch for it.
     
    Last edited: Sep 29, 2010
  12. nikhiljain

    New Member

    Aug 26, 2010
    3
    0
    u'll need to use a converter like FT232 for UART 2 USB conversion
     
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