Questions about FTDI Cables

Discussion in 'General Electronics Chat' started by bluexdynasty, Oct 24, 2014.

  1. bluexdynasty

    Thread Starter New Member

    Oct 3, 2014

    I was wondering if the RTS and CTS lines can be left floating/ unconnected on an FTDI cable or should they be connected to GPIOs on my MCU? The reason why I want to use an FTDI cable is more for the RX, and TX lines to program my device.

    In addition, I read that the VCC line (red wire) is 5V I'm assuming that this 5V is supplying from the cable to the board, and thus can also be left unconnected? The cable I found is

    That's because the device I have is a battery powered device (3.3V) and I don't want to damage anything in the process, so I'm mostly looking for some confirmation to be safe, since I haven't used one of these before.

    Thanks in advance for the help!
  2. cmartinez

    AAC Fanatic!

    Jan 17, 2007

    I've been using FTDI products for years and I can tell you that their UART chipset is a slice of heaven. They're the best converters out there, highly reliable and robust with the highest quality drivers (they're the complete opposite of the crappy Prolific brand)

    That said, I can give you a full answer to your question:
    1.- Yes, the RTS and CTS lines can be left floating without affecting performance in any way.
    2.- Yes, you can leave the 5V cable unconnected, FTDI put it there in case you want to power your electronics from the USB, sparing you the need for a battery or an external adapter. However, the ground (black) cable MUST be connected to your circuit's ground for things to work at all.

    Happy prototyping !
    bluexdynasty likes this.
  3. bluexdynasty

    Thread Starter New Member

    Oct 3, 2014
    That's great!

    Thanks for the very quick response!

    Learning something new everyday :)