TTL to USB converter cable.

Discussion in 'Embedded Systems and Microcontrollers' started by withloveshyam, Oct 25, 2010.

  1. withloveshyam

    Thread Starter New Member

    Mar 20, 2010
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    Hi,
    I wanted to know if the TTL to USB cable like the one in the link shown below can be replaced by a MAX3232 level converter circuit and a RS232 to USB converter.

    USB FTDI TTL-232 cable [TTL-232R 3.3V] ID: 70 - $20.00 : Adafruit Industries, Unique & fun DIY electronics and kits

    The MAX3232 converts the TTL to RS232 logic...I connect the 3 pins, the Txd, Rxd,Gnd on the RS232 side of the converter (RS232 to USB)
    The other end of the converter, i.e USB end is connected to the PC.

    Please let me know if this will produce exactly the same output as the FTDI TTL to 232 cable.

    I am not getting the proper output in my project so wanted to check if it was because of this.

    Basically i want to transmit data from the MCU to Laptop.

    Thanks very much...
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
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  3. t06afre

    AAC Fanatic!

    May 11, 2009
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    Your link is missing. But as far as I can see. The TTL to USB cable may bee replaced by a more typical RS232 to USB converter. If you use MAX232 type circuit on your MCU board. But in order to avoid confusion. Perhaps you can draw a simple schematic?
     
  4. withloveshyam

    Thread Starter New Member

    Mar 20, 2010
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    Last edited: Apr 7, 2011
  5. t06afre

    AAC Fanatic!

    May 11, 2009
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    Can you post you schematics also?
     
  6. withloveshyam

    Thread Starter New Member

    Mar 20, 2010
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    Can I know what schematics you are referring to?

    The MAX 3232 setup(MAX3232 and capacitors setup) is the normal one that i found online. I have checked the functionality of this circuit by transmitting and receiving data from PC and it works fine.

    RS232 to USB converter was bought as such readymade.

    Then the PIC MCU connections are exactly as given in the project page that i have given the link for.

    If you can tell me what exactly you want me to tell, that will be great.

    Thanks for the help.
     
  7. t06afre

    AAC Fanatic!

    May 11, 2009
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    Do you connect R2 (on the V+ side) to anything on your TTL to USB cable ?
    [​IMG]
     
  8. withloveshyam

    Thread Starter New Member

    Mar 20, 2010
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    Many Thanks for t reply.

    I actually need some help and advice from you.

    I am skipping the Optoisolator (IC2) part in my design and directly connecting the output from pin 2(of IC1, i.e the PIC) to the Txd line of the MAX3232 and the gnd (of IC1, i.e the PIC) to the gnd of the MAX3232.

    Can you please tell me if this setup of mine will work same as the above circuitry(the one in the diagram) and if it will produce the same results as the above one.

    For your information i am not using the USB to TTL cable.
    I am just using the MAX3232 setup and RS232 to USB converter.

    I am not very much familiar with discrete electronics and I am struggling with this one.

    If you could help me out it will be great.

    Thanks in advance.
     
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