:PROPERTIES:
:ID:       d97fde4a-0e91-40f9-ac57-d0cd67295d14
:END:
#+title: ESP8266
* Best pins to use
| Label | GPIO   | Input         | Output                | Notes                                                            |
|-------+--------+---------------+-----------------------+------------------------------------------------------------------|
| D0    | GPIO16 | no interrupt  | no PWM or I2C support | HIGH at boot used to wake up from deep sleep                     |
| D1    | GPIO5  | OK!           | OK!                   | often used as SCL (I2C)                                          |
| D2    | GPIO4  | OK!           | OK!                   | often used as SDA (I2C)                                          |
| D3    | GPIO0  | pulled up     | OK!                   | connected to FLASH button, boot fails if pulled LOW              |
| D4    | GPIO2  | pulled up     | OK!                   | HIGH at boot connected to on-board LED, boot fails if pulled LOW |
| D5    | GPIO14 | OK!           | OK!                   | SPI (SCLK)                                                       |
| D6    | GPIO12 | OK!           | OK!                   | SPI (MISO)                                                       |
| D7    | GPIO13 | OK!           | OK!                   | SPI (MOSI)                                                       |
| D8    | GPIO15 | pulled to GND | OK                    | SPI (CS) Boot fails if pulled HIGH                               |
| RX    | GPIO3  | OK            | RX pin                | HIGH at boot                                                     |
| TX    | GPIO1  | TX pin        | OK                    | HIGH at boot debug output at boot, boot fails if pulled LOW      |
| A0    | ADC0   | Analog Input  | X                     |                                                                  |