1. Introduction

The FT232RL is USB-to-Serial converter based on an FTDI chip. It is available in two level-shifting variants: 3v3 and 5v. Because of that, the converter comes in handy when one is going to connect the USARTs from a micro controller to a PC. Since most modern PCs don’t have a RS232 port integrated, the USB connector is an other plus. The breadboard version (from sparkfun) of the converter exposes all pins to a 2,54mm grid.

2. Features

The main features of the FT232RL are:

  • Level shifting from 3v3 or 5v (depending on a resistor on the bottom side).
  • Full support for HW and SW flow control.
  • Up to 115200 Baud.

3. Minimal Usage Example

The most simple usage example for a serial port one can think of, is bridging the Rx and Tx pins. Thus, everything you send out the serial port is echoed back.

For this minimalistic test setup, no external power source is needed. Just connect the TxD pin to the RxD pin of the converter, and you are done. Connect the converter to the USB port of your PC, fire up a serial terminal and type some characters. Make sure not to enable local echo, otherwise all characters you type show up twice on your screen.

On Linux you could use “screen” as a terminal:

screen /dev/tyUSB0 38400

To exit your screen session type “Ctrl+a k”.


  • gschem schematic of the usage example
  • gschem schematic of the FT232RL breadboard converter

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