Description: Introducing the 3.3V SparkFun FT231X Breakout board, complete with the full UART hardware handshake feature! The pinout of this board matches the FTDI cable to work with official Arduino and cloned 3.3V Arduino boards. It can also be used for general serial applications. This board still brings out the DTR pin as opposed to the RTS pin of the FTDI cable. The DTR pin allows an Arduino target to auto-reset when a new Sketch is downloaded. This is a really nice feature to have and allows a sketch to be downloaded without having to hit the reset button. This board will auto reset any Arduino board that has the reset pin brought out to a 6-pin connector.
The coolest thing about the FT231X Breakout is that we have broken out ALL the pins for your use, making this board all the more hackable! It also uses a common microUSB jack.
One of the features of this board is a jumper on the back, which allows the VCC output to be configured to either 3.3V or 5V. This board ships default to 5V, but you can cut the default trace and add a solder jumper if you need to switch to 3.3V. It should be noted, however, that the max input of the FT231X through the pin labeled 3.3 on the breakout is only 3.3V but it can operate down to 1.8V with external pull ups. I/O is still 5V tolerant.
Based on 3 ratings:
The board can switch between 3.3v and 5v output, but only if you cut the contact on the bottom and solder on your own switch. It was very difficult to do this. I followed the advice of one of the commenters and hot glued a tiny switch to the bottom.
It can power my ESP8266 board on its own
Four stars because I think it’s probably just as good or better than the other FTDI breakouts on the site
It works great.
Not immediately obvious is the need to scrape off the VCC connection from 5V and then solder the 3.3V onto it.
To program the microcontroller, I used these connections: (Sparkfun board) -> (Atmega328P Microcontroller) // VCC->VCC // GND->GND // RX->TX // TX->RX // DTR->0.1uF Cap->Reset pin
I am pleased that the drivers work with my desktop processor, unlike the previous FTDI cable.