GPIO2 Anomaly

Schematics, Example Code and Q&A
Airhead
Posts: 5
Joined: Sun Feb 24, 2019 4:43 pm

GPIO2 Anomaly

Unread post by Airhead »

I have found that a sketch (Arduino IDE) will not Upload with an LED between +3V and GPIO2.
It's OK with an LED between +3 and GPIO4 though.

"A fatal error occurred: Failed to connect to ESP32: Timed out waiting for packet header

If it's a red LED then it bombs; if it's a yellow LED then it's OK.

(Red has a 240Ω resistor, Yellow has 270Ω resistor).
Airhead
Posts: 5
Joined: Sun Feb 24, 2019 4:43 pm

Re: GPIO2 Anomaly

Unread post by Airhead »

OK, I found the answer - in the Espressif datasheet.
GPIO2 is a "strapping pin" and its condition determines the boot state.
(GPIO5 is a "strapping pin", too.)

It's all there in 2.4
https://www.espressif.com/sites/default ... eet_en.pdf
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