Configuration
Revision as of 12:57, 20 June 2017 by Grovkillen (talk | contribs)
This page will tell you more about some things that you may need to know about when using the ESP8266 units (boot states of GPIOs, input voltages, etc. etc). Please beware that this is a generic list, your specific ESP unit might have other restrictions than these general ones. Refer to the ESP Hardware page if you want to be sure what GPIOs that are available and their usefulness.
GPIO on ESP8266
| GPIO Number | GPIO Name | Boot State | Precautions and information |
|---|---|---|---|
| 0 | D3 | HIGH for boot LOW for serial programming |
Pullup resistor on most boards |
| 1 | Used as serial (TX) May be used but observe that signal might flicker due to serial activity during boot. | ||
| 2 | D4 | HIGH for boot HIGH for serial programming |
Connected to onboard LED (low active) Used as serial1 (TX1) |
| 3 | Used as serial (RX) May be used but observe that signal might flicker due to serial activity during boot. | ||
| 4 | D2 | Generally used as SDA (I2C) | |
| 5 | D1 | Generally used as SCL (I2C) | |
| 6 | Do not use! Reserved for SPI + flash | ||
| 7 | Do not use! Reserved for SPI + flash | ||
| 8 | Do not use! Reserved for SPI + flash | ||
| 9 | D11 | Do not use! Reserved for SPI + flash | |
| 10 | D12 | Use with caution! Reserved for SPI + flash | |
| 11 | Do not use! Reserved for SPI + flash | ||
| 12 | D6 | ||
| 13 | D7 | ||
| 14 | D5 | ||
| 15 | D8 | LOW for boot | Pulldown resistor on most boards |
| 16 | D0 | No PWM. No internal pullup available. Used in sleep mode for wakeup |
