Frequently Asked Questions
What should I watch out for on the NodeMCU ESP8266?
D3 (GPIO0), D4 (GPIO2) must be HIGH at boot; D8 (GPIO15) must be LOW. Only one analog pin (A0), 0-1 V on the chip, 0-3.3 V on NodeMCU boards thanks to a divider. D0 (GPIO16) has no PWM/interrupt; wire it to RST for deep-sleep wake.
Is the NodeMCU ESP8266 5 V tolerant?
3.3 V logic. Many modern sensors are 3.3 V, so check before connecting them.
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