Ven...R shared a link.
29 July 2016
Ask Hackaday: Is The ESP8266 5V Tolerant? | Hackaday
Ask Hackaday: Is The ESP8266 5V Tolerant?
The ESP8266 is the reigning WiFi wonderchip, quickly securing its reputation as the go-to platform for an entire ecosystem of wireless devices. There's nothing that beats the ESP8266 on a capabilit...
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Roy St...: I don't know if the official specs are, but I've run dozens of ESP's with 5v in on the serial port for months on end with no ill effects.
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Gop...Ma...: Me too.... Have always directly connected ESP's serial port to Arduino directly.... And all the seven or eight projects have been running fine for more than a year, year and a half.... Recently have verifies that even the input supply voltage for ESP can go up to 4.2v
Eva...L...: Me too
Venk...R...: Stevens Which serial device have you used ? because the one's which I have are all 3.3v logic and a 5v and 3.3v option board
Roy St...: Straight from a Atmega328.
Bao...Z...: you can use 5v, as long as you don't dump 5v rail onto the IOs. The ESD protection diodes will clamp the input.
But seriously what is so hard to do a proper level conversion?
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Venk...R...: Yeah level conversion is a safe practice. There is always a chance that we can push for extra but it might not be good in long run.
Teo...S...A...: i can reply officially here: it is 5V tolerant at the IO. while the supply voltage is at 3.3V.
94 Likes
Ba...Z...: How about ESP32?
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Ven...R...: and ESP8285 ??
Teo...S...A: ESP32 and ESP8285 are both 5V tolerant as well.
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Teo...S...A...: but for ESP32, it is a very complicated matter. it supports 1.8V operations too... i don't know where to start...
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Urm...P...: Omg
Urm...P...: Is that for battery operated case?
Teo...S...A...: actually not. but many memory devices are moving towards 1.8V operations, and we would be compatible with them as well.
Urm...P...: Wow! So does it have multiple voltage domains? I hope not...
Ch...G...: Thank you for your very welcome official confirmation. This question crops up almost every day and there are a large number of uses who refuse to accept it because it is not in your latest spec sheets although it was in an earlier one. I…See more
Teo...S...A...: the reason is too many users took it to mean that the chip is 5 V tolerant. When we say 5 V tolerant, we are only referring to the IOs. So some users mistook this to make that they can power the chip entirely off the 5 V supply. The correct usage is to use 5 V open for these 5 V tolerant pins, and only via only drain configuration.
Ch...G...: I am surprised by their "confusion" as I understood it perfectly :). By omitting it you have boosted sales of logic level converters and have given us admins a lot of "boring" questions to handle 
Nevertheless you have given us a fantastic device - well done ??
Teo...S...A...: I understand, but the time needed to do the iterations when mistakes were made, was too long. when the product was launched 5 V WiFi modules (with DCDC) were the norm. Many users saw "5 V" written in the specs and thought it could be a 1-1 replacement for such modules.
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Ur...P...: We have all seen ESP01 working with Arduino boards. Why so much confusion?
Ba...Z...: I did some more investigation. Is ESP8266 I/O really 5V tolerant? - Digital Me
Ma...E...: Nice investigation!
? ? ... ? ? ...: Original link no longer works... so what's the test result?
Ba...Z...: Is ESP8266 I/O really 5V tolerant? - Digital Me
2 Like
JW...S...: You know, that investigation, and the info on the link, is quoting a comment two above yours. It would have been easier to just say "scroll up to Teo...S...A's comment."
Edit: noch einen zuvor übersehenen Namen entfernt.
