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

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By HermannSW
#19433 Just saw what GPIO15 is about, from:

GPIO15 being HIGH on startup selects boot from SD card, so it should be connected to GND normally (on startup):

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By GeorgeIoak
#19436 Yes, you are correct, you should use a resistor to pull GPIO15 to GND. Depending on what you are doing with the LED on GPIO2 you might want to adjust that resistor value. I don't recall the drive strength of the ESP8266 but putting 10mA through the LED is usually more than enough to make it bright. Just use Ohms law (V=IR), where V in this case is 3.3-Vf and Vf is the forward voltage of the LED you're using.