ESP8266 Platform¶
This component contains platform-specific options for the ESP8266 platform.
# Example configuration entry
esp8266:
board: nodemcuv2
framework:
version: recommended
Configuration variables:¶
board (Required, string): The PlatformIO board ID that should be used. Choose the appropriate board from this list (the icon next to the name can be used to copy the board ID). This only affects pin aliases, flash size and some internal settings, if unsure choose a generic board from Espressif such as
esp01_1m
.framework (Optional): Options for the underlying framework used by ESPHome.
version (Optional, string): The base framework version number to use, from esp8266 arduino releases. Defaults to
recommended
. Additional valuesdev
: Use the latest commit from https://github.com/esp8266/Arduino, note this may break at any timelatest
: Use the latest release from https://github.com/esp8266/Arduino/releases, even if it hasn’t been recommended yet.recommended
: Use the recommended framework version.
source (Optional, string): The PlatformIO package or repository to use for the framework. This can be used to use a custom or patched version of the framework.
platform_version (Optional, string): The version of the platformio/espressif8266 package to use.
restore_from_flash (Optional, boolean): Whether to store some persistent preferences in flash memory. Defaults to
false
.board_flash_mode (Optional, string): The SPI mode of the flash chip. One of
qio
,qout
,dio
anddout
. Defaults todout
for compatibility with all chips. Note: on the next OTA update the actual flash mode is automatically detected and changed to the appropriate one.early_pin_init (Optional, boolean): Specifies whether pins should be initialised as early as possible to known values. Recommended value is
false
where switches are involved, as these will toggle when updating the firmware or when restarting the device. Defaults totrue
.
GPIO Pin Numbering¶
Many boards have a pin numbering for the exposed pins that is different from the internally used
ones. ESPHome tries to map the silk-screen pin numbers into the internal pin numbers with a few
boards, but for generic ESP8266 boards it is often required to just use the internal pin numbers.
To do this, just prefix all pins with GPIO
, for example GPIO0
for the pin with the internal pin
number 0.
Some notes on the pins:
GPIO6
-GPIO11
,GPIO0
,GPIO2
andGPIO15
are often already used by the internal flash interface and boot mode detection. So it’s best to avoid using these pins.GPIO17
additionally has an ADC connected to it. See the Analog To Digital Sensor to read voltages (in the range from 0 to 1.0V) on this pin.
# Example configuration entry
esphome:
name: livingroom
esp8266:
board: nodemcuv2
binary_sensor:
- platform: gpio
name: "Pin GPIO17"
pin: GPIO17
Special Pins¶
|
Controls Boot Mode |
|
UART TX pin |
|
Controls Boot Mode |
|
UART RX pin |
|
SDIO/Flash CLK pin |
|
SDIO/Flash Data 0 pin |
|
SDIO/Flash Data 1 pin |
|
SDIO/Flash Data 2 pin (qio/qout only) |
|
SDIO/Flash Data 3 pin (qio/qout only) |
|
SDIO/Flash CMD pin |
|
Attached to Hardware SPI controller MISO |
|
Attached to Hardware SPI controller MOSI |
|
Attached to Hardware SPI controller CLK |
|
Controls Boot Mode; Attached to Hardware SPI controller CS |
|
Special pin that can be accessed from RTC, and is Deep-Sleep wakeup pin |
TOUT aka |
ADC pin for measuring voltages, can only be used as analog input pin |
This means effectively only the following pins can be used as general purpose GPIO:
Pin |
Restrictions |
State after Reset |
|
If HIGH on boot |
Weak Pull Up |
|
If HIGH on boot |
Weak Pull Up |
|
High Impedance |
|
|
High Impedance |
|
|
Weak Pull Up |
|
|
Weak Pull Up |
|
|
Weak Pull Up |
|
|
Weak Pull Up |
|
|
If LOW on boot |
Weak Pull Up |
|
Has pull-down (but no pull-up) resistor |
Weak Pull Down |
Boot Modes¶
On each boot, the ESP8266 will check three pins to determine in which boot mode to enter. There are three boot modes:
Mode |
|
|
|
|
Boot from Flash (normal) |
HIGH |
HIGH |
LOW |
3 |
Download Code from UART |
LOW |
HIGH |
LOW |
1 |
Boot from SD-Card |
ANY |
ANY |
HIGH |
4-7 |
You can identify these on boot-up by looking at the UART output, the first number
in the boot mode:
line tells you what mode was selected
ets Jan 8 2013,rst cause:4, boot mode:(3,6)
The first lines when viewing the UART logs might have unrecognized characters. This is because the effective baudrate of the ESP8266 bootloader is 74800, whereas the program uses 115200.
Reset Causes¶
Additionally, the first line also contains the reset cause. These reset causes are documented:
0 |
Undefined |
1 |
Power On Reboot |
2 |
External reset or deep-sleep wakeup |
4 |
Hardware WDT reset |
After a software reset, the reset cause will not change.
Electrical Characteristics¶
Parameter |
Min. |
Typical |
Max. |
Unit |
Operating Temperature |
-40 |
125 |
°C |
|
Working Voltage |
2.5 |
3.3 |
3.6 |
V |
|
-0.3 |
0.25*V_IO |
V |
|
|
0.75*V_IO |
3.6 |
V |
|
|
0.1*V_IO |
V |
||
|
0.8*V_IO |
V |
||
|
12 |
mA |
||
Power Consumption in Deep Sleep |
20 |
µA |
||
Power Consumption in Active Mode |
120 |
mA |
Source: ESP8266EX datasheet
The internal pull up/down resistors have values of 30kΩ to 100kΩ (source).