ESP8266 -> FTDI -> USB Mac

I followed the wiring on this page: http://williamdurand.fr/2015/03/17/playing-with-a-esp8266-wifi-module/

ESP8266 to FTDI Wiring

I was communicating with it via Serial at 115200. I issued a AT+UART_DEF=9600,8,1,0,0 and a few seconds later I looked over and it was smoking.

Burnt ESP8266

I bought 2 of these. The previous one I had wired to an Arduino Nano running through a logic level converter. That one only returns Exception (28) over and over again after issuing that same command.

On both units AT+GMR returned:

AT version:  8 2015 14:45:58)
SDK version:1.3.0

Are these units too hard to use? What did I do to burn it out?


Answer given was that I fed it 5v instead of 3.3v. Obvious. I didn't think I did but I checked the output of the FTDI and sure enough it was 5.1v. So why does the output on it say 3V3 ? I thought that meant that it was 3.3v...

3V3 Doesn't mean 3.3v?

Should have checked it first.

2 Answers 2


You supplied 5V to a device that only takes up to 3.6V. Heat generated by the excessive power did the rest.

  • I'm checkmarking you cause obviously you are correct. But I hope to also get an answer to why 3V3 doesn't mean 3.3V? Why not label it as VCC or +5V instead of 3V3 if it's not 3 volts?
    – badweasel
    May 13, 2016 at 4:29
  • 1
    The easy answer is that you have a defective FTDI device. It should be 3.3V, but clearly it is not. May 13, 2016 at 4:30
  • Also, the FTDI device likely does not supply enough current on the 3.3V rail to run the ESP8266 module to its full potential regardless; you should get a separate 3.3V regulator and connect it to that. May 13, 2016 at 4:31
  • I bought these but they say 150ma on the back.. amazon.com/XCSOURCE-Converter-Bi-Directional-Module-TE291/dp/…
    – badweasel
    May 13, 2016 at 4:32
  • Those are level shifters, not voltage regulators. May 13, 2016 at 4:33

I checkmarked Ignacio's answer because it was correct. But I wanted to leave an answer also as to HOW I supplied 5v when I thought I was supplying 3.3v. Maybe it will help someone else.

FTDI backside showing 3.3 or 5v jumpers

The backside of this FTDI module has a jumper to select 3.3 or 5v and the default is set to 5v. I needed to cut the default trace line connecting to 5v and solder my own jumper to switch it to 3.3v. I should have double checked the voltage before powering it up. New ESP01's on order.

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