Use this forum to chat about hardware specific topics for the ESP8266 (peripherals, memory, clocks, JTAG, programming)

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By Atlantis
#32193 In few places on the Web I encountered opinion, that GPIO2 pin should be pulled up to VCC, because otherwise it could mess up booting process. Most tutorials doesn't mention it at all. Can I leave this pin unconnected?
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By martinayotte
#32197 To boot properly, both GPIO2 and GPIO0 needs to be HIGH.
https://github.com/esp8266/esp8266-wiki ... ot-Process
Although some people said that ESP has internal pullups, but they are known to be too weak, so it is strongly recommended to have some external ones on all required pins : CH_PD, RES, GPIO2 and GPIO0 to HIGH and GPIO15 to LOW.