ESP8266 Community Forum

Looking on the Internet, I see many people use a level shifter from 5V to 3.3V on the Rx port. Usually people use the simple voltage divider, 1kOhm+2.2kOhm.
But I also see other reports of it working perfectly with 5V on the Rx port, i.e. connecting the Rx directly to an Arduino Tx.

So is there any definitive answer here ? Will it run with 5V TTL signals or not ? What is it that kills the ESP8266 ?
I do have a LM3117 3.3V regulator to power it.

I have some 1N4002, forward voltage 1.1V. I guess 2 of these in series would work just as well as the resistor divider, and would be simpler since they are in line, where the voltage divider would need an extra wire to GND.

I also found this interesting:
viewtopic.php?f=13&t=8693&hilit=5v&start=4
But he is doing output only I think. I need to connect the module to an APM Flight controller (Atmel 328P), 2-way. 99% of the data will come from the APM to the ESP-01. Want to keep it light and simple.

Just a comment on myself.

I see in the datasheet, page 17-18:

All digital IO pins are protected from over-voltage with a snap-back circuit connected between the
pad and ground. The snap back voltage is typically about 6V, and the holding voltage is 5.8V. This provides protection from over-voltages and ESD. The output devices are also protected from reversed voltages with diodes.

Some people read this as the esp8266 IS 5V tolerant on i/o.

i power all my esp modules with 5v. and 5v level on its input pins.

villTech wrote:i power all my esp modules with 5v. and 5v level on its input pins.

Have a good luck with ESP longevity ...