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USB to Serial TTL Breakout Board

Discussion in 'The Projects Forum' started by Rosbife, Feb 1, 2013.

  1. Rosbife

    Thread Starter New Member

    Jan 17, 2013
    Hello everyone, I once posted my project here, with a few doubts, and people asked me to post my files before making my own board when I was done with them.

    So here it is. The schematic should be final, unless I change the decoupling around, which is the only thing I've been looking into recently.
    (well actually there is a chance I might be changing the handshaking and CBUS parts, I'm still waiting to hear from my "team" if they're necessary or not)

    As for the layout, well, this version was only something I started playing around with but since it kind of turned out okay ( ? I'm a complete novice at this), I tried to improve it a bit and perhaps it might fit.
    It should be noted it should be top-layer-only, but since it seemed kind of impossible to me (if I wanted to keep things minimally compact and without a lot of jumpers, that is), there are 3 or 4 bottom-layer connections which I will probably be connecting with wires underneath the board.

    Quick summary:

    -USB <-> UART TTL;
    -FT230XS by FTDI;
    -Full Speed (Not HS);
    -I was asked to include a header in parallel with the USB signal lines, hence the header in front of the USB connector;
    -Header with basic UART-side signals, TX/RX/Power;
    -Header with handshaking (CTS# RTS#) and GPIOs (minus 1 and 2 which are being used to drive the LEDs);
    -3 LEDs for Power, Transmit and Receive signaling;
    -pretty standard decoupling, I am still trying to make full sense of all associated with it, but these are FTDI recommended either way;
    -a ferrite bead for EMI shielding on the power line;
    -lastly, pads for a resistor (or eventually a cap) between shielding and GND. Shielding connections seem to be the target of much discussion, but this was what FTDI recommended as well. Since I'm using their chip, I thought it was good practice.

    (note: as you can see, I placed 3 caps near the IC and the 3 other ones near the USB source. I'm not sure about this at all, but it was what I could make of their use)

    That should cover it. I guess all I wish is for anyone who sees obvious mistakes, or something which could be substantially improved, help me out and note it down :p.
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