mirror of
https://github.com/letscontrolit/ESPEasy.git
synced 2026-09-12 09:36:59 +00:00
TD-er
617c4d1ac8
ESP32 can keep track of the pin state of a number of pins at boot. With this update these pin states will be send at boot as an event, so one may act on it during boot. Possible use case: Detect voltage and immediately go to sleep again. Later features may use these too to enter for example a service mode.
290 lines
7.9 KiB
ReStructuredText
290 lines
7.9 KiB
ReStructuredText
GPIO
|
|
****
|
|
|
|
|
|
|
|
Best pins to use on ESP8266
|
|
---------------------------
|
|
|
|
Most board do not have made all pins available.
|
|
The NodeMCU boards have almost all usable pins made available and some which need special attention.
|
|
|
|
.. list-table:: Best pins to use (best to worst)
|
|
:widths: 10 25 25 40
|
|
:header-rows: 1
|
|
|
|
* - GPIO
|
|
- Input
|
|
- Output
|
|
- Remarks
|
|
* - 5 (D1)
|
|
- :green:`OK`
|
|
- :green:`OK`
|
|
- Often used for I2C
|
|
* - 4 (D2)
|
|
- :green:`OK`
|
|
- :green:`OK`
|
|
- Often used for I2C
|
|
* - 14 (D5)
|
|
- :green:`OK`
|
|
- :green:`OK`
|
|
-
|
|
* - 12 (D6)
|
|
- :green:`OK`
|
|
- :green:`OK`
|
|
-
|
|
* - 13 (D7)
|
|
- :green:`OK`
|
|
- :green:`OK`
|
|
-
|
|
* - 0 (D3)
|
|
- :yellow:`pulled up`
|
|
- :yellow:`OK`
|
|
- :yellow:`Boot fail if pulled low`
|
|
* - 2 (D4)
|
|
- :yellow:`pulled up`
|
|
- :yellow:`OK`
|
|
- :yellow:`Boot fail if pulled low`
|
|
* - 15 (D8)
|
|
- :red:`pulled to GND`
|
|
- :yellow:`OK`
|
|
- :yellow:`Boot fail if pulled high`
|
|
* - 16 (D0)
|
|
- :red:`High at boot, pull down to GND`:yellow:`no interrupt`
|
|
- :yellow:`no I2C support`
|
|
- Used to wake up from deep sleep
|
|
* - 9 (SD2)
|
|
- :red:`High at boot`
|
|
-
|
|
- :yellow:`See notes`
|
|
* - 10 (SD3)
|
|
- :red:`High at boot`
|
|
-
|
|
- :yellow:`See notes`
|
|
* - 3 (RX)
|
|
- :yellow:`High at boot`
|
|
- :red:`is RX`
|
|
- RX channel of serial0
|
|
* - 1 (TX)
|
|
- :red:`is TX`
|
|
- :yellow:`debug output at boot`
|
|
- :yellow:`Boot fail if pulled low`
|
|
|
|
|
|
The labels used in the tabel above are the labels on NodeMCU boards.
|
|
|
|
Sources used:
|
|
|
|
* `The Hook Up - How To: Pick the right pins on the NodeMCU ESP8266 and ESP32 <https://www.youtube.com/watch?v=7h2bE2vNoaY>`_
|
|
* `ESP8266 GPIO pin "features" <https://docs.google.com/spreadsheets/d/1pQuBocanzCZJ3KPUpu3VvpOOBzboqXDuwQDVP5UYcXc/edit#gid=0>`_
|
|
* `Rabbithole - ESP8266 GPIO Behaviour at Boot <http://rabbithole.wwwdotorg.org/2017/03/28/esp8266-gpio.html>`_
|
|
|
|
Special notes on GPIO 6 - 11
|
|
~~~~~~~~~~~~~~~~~~~~~~~~~~~~
|
|
|
|
Almost any ESP8266 board has a flash chip connected to some or all of GPIO6-GPIO11.
|
|
|
|
GPIO 9 & 10 can be used on ESP8285, since that chip has 1 MB flash embedded and is not using those pins.
|
|
One or both of pins may sometimes also be available on ESP8266 boards, depending on the flash used and the flash operation mode.
|
|
|
|
* Quad IO (QIO) uses 4 lines for data (6 pins total)
|
|
* Dual IO (DIO) uses 2 lines for data (4 pins total)
|
|
* Standard uses a single line for data (3 pins total)
|
|
|
|
It is best not to use any of the GPIO pins 6 - 11.
|
|
|
|
|
|
Special notes on GPIO 16
|
|
~~~~~~~~~~~~~~~~~~~~~~~~
|
|
|
|
GPIO-16 is a special pin.
|
|
The RTC will send a short (low) pulse when the sleep timer does send a wake-up signal.
|
|
|
|
In order to wake from deep sleep, GPIO-16 has to be connected to the RST pin.
|
|
If connected, this pin should not be used as GPIO pin, or else the module will reboot.
|
|
|
|
Other limitations are:
|
|
|
|
* GPIO16 has a built-in pull-down resistor (all others have built-in pull-up)
|
|
* To enable the pull-down resistor for GPIO16, you have to use ``INPUT_PULLDOWN_16``
|
|
|
|
|
|
Best pins to use on ESP32
|
|
-------------------------
|
|
|
|
There is also a NodeMCU version using the ESP32.
|
|
Fortunately the designers used the GPIO numbers as labels on the board.
|
|
|
|
.. list-table:: Sorted in reverse GPIO pinnr order
|
|
:widths: 10 25 25 40
|
|
:header-rows: 1
|
|
|
|
* - GPIO
|
|
- Input
|
|
- Output
|
|
- Remarks
|
|
* - 36
|
|
- :green:`OK`
|
|
-
|
|
- :yellow:`input only`
|
|
* - 39
|
|
- :green:`OK`
|
|
-
|
|
- :yellow:`input only`
|
|
* - 35
|
|
- :green:`OK`
|
|
-
|
|
- :yellow:`input only`
|
|
* - 34
|
|
- :green:`OK`
|
|
-
|
|
- :yellow:`input only`
|
|
* - 33
|
|
- :green:`OK`
|
|
- :green:`OK`
|
|
-
|
|
* - 32
|
|
- :green:`OK`
|
|
- :green:`OK`
|
|
-
|
|
* - 27
|
|
- :green:`OK`
|
|
- :green:`OK`
|
|
-
|
|
* - 26
|
|
- :green:`OK`
|
|
- :green:`OK`
|
|
-
|
|
* - 25
|
|
- :green:`OK`
|
|
- :green:`OK`
|
|
-
|
|
* - 23
|
|
- :green:`OK`
|
|
- :green:`OK`
|
|
-
|
|
* - 22
|
|
- :green:`OK`
|
|
- :green:`OK`
|
|
-
|
|
* - 21
|
|
- :green:`OK`
|
|
- :green:`OK`
|
|
-
|
|
* - 19
|
|
- :green:`OK`
|
|
- :green:`OK`
|
|
-
|
|
* - 18
|
|
- :green:`OK`
|
|
- :green:`OK`
|
|
-
|
|
* - 17
|
|
- :green:`OK`
|
|
- :green:`OK`
|
|
-
|
|
* - 16
|
|
- :green:`OK`
|
|
- :green:`OK`
|
|
-
|
|
* - 15
|
|
- :green:`OK`
|
|
- :green:`OK`
|
|
- :yellow:`output PWM signal at boot, internal pull-up` Silences boot messages when pulled low at boot.
|
|
* - 14
|
|
- :green:`OK`
|
|
- :green:`OK`
|
|
- :yellow:`output PWM signal at boot`
|
|
* - 13
|
|
- :green:`OK`
|
|
- :green:`OK`
|
|
-
|
|
* - 12
|
|
-
|
|
- :green:`OK`
|
|
- :yellow:`Boot fail if pulled high` :red:`May damage flash if low at boot on 1.8V flash chips`
|
|
* - 9, 10, 11
|
|
- :red:`High at boot`
|
|
-
|
|
- :red:`See notes`
|
|
* - 6, 7, 8
|
|
-
|
|
-
|
|
- :red:`See notes`
|
|
* - 5
|
|
- :green:`OK`
|
|
- :green:`OK`
|
|
- :yellow:`output PWM signal at boot, internal pull-up`
|
|
* - 4
|
|
- :green:`OK`
|
|
- :green:`OK`
|
|
- :yellow:`Internal pull-down`
|
|
* - 3 (RX)
|
|
- :yellow:`High at boot`
|
|
- :red:`is RX`
|
|
- RX channel of serial0
|
|
* - 2
|
|
- :green:`OK`
|
|
- :green:`OK`
|
|
- Often connected to LED, :yellow:`Internal pull-down`
|
|
* - 1 (TX)
|
|
- :red:`is TX`
|
|
- :yellow:`debug output at boot`
|
|
- TX channel of serial0
|
|
* - 0
|
|
- :yellow:`pulled up`
|
|
- :yellow:`OK`
|
|
- :yellow:`Boot fail if pulled low & output PWM signal at boot`
|
|
|
|
Source used:
|
|
|
|
* `The Hook Up - How To: Pick the right pins on the NodeMCU ESP8266 and ESP32 <https://www.youtube.com/watch?v=7h2bE2vNoaY>`_
|
|
* `Random Nerd Tutorials - ESP32 Pinout Reference: Which GPIO pins should you use? <https://randomnerdtutorials.com/esp32-pinout-reference-gpios/>`_
|
|
|
|
Special notes on GPIO 6 - 11
|
|
~~~~~~~~~~~~~~~~~~~~~~~~~~~~
|
|
|
|
Almost any ESP32 board has a flash chip connected to some or all of GPIO6-GPIO11.
|
|
|
|
It is best not to use any of the GPIO pins 6 - 11.
|
|
|
|
GPIO 6, 7 & 8 may output some PWM signals at boot.
|
|
GPIO 9, 10 & 11 output high at boot and may fail to boot of pulled either high or low.
|
|
|
|
Boot Strapping Pins
|
|
~~~~~~~~~~~~~~~~~~~
|
|
|
|
The logic state of some pins during boot determines how the ESP32 will boot and into what mode.
|
|
|
|
* GPIO-0: Low: flash mode. High: Normal execution mode
|
|
* GPIO-2: Must also be either left unconnected/floating, or driven Low, in order to enter the serial bootloader. In normal boot mode (GPIO0 high), GPIO2 is ignored.
|
|
* GPIO-12: If driven High, flash voltage (VDD_SDIO) is 1.8V not default 3.3V. Has internal pull-down, so unconnected = Low = 3.3V. May prevent flashing and/or booting if 3.3V flash is used and this pin is pulled high, causing the flash to brownout. See the ESP32 datasheet for more details.
|
|
* GPIO-15: If driven Low, silences boot messages printed by the ROM bootloader. Has an internal pull-up, so unconnected = High = normal output.
|
|
|
|
There is a number of pins that will be read at boot and their value is displayed in the "boot" value:
|
|
|
|
.. code-block:: none
|
|
|
|
ets Jun 8 2016 00:22:57
|
|
rst:0x1 (POWERON_RESET),boot:0x3 (DOWNLOAD_BOOT(UART0/UART1/SDIO_REI_REO_V2))
|
|
|
|
``boot:0xNN (DESCRIPTION)`` is the hex value of the strapping pins, as represented in the GPIO_STRAP register. The individual bit values are as follows:
|
|
|
|
* ``0x01`` - GPIO5
|
|
* ``0x02`` - MTDO (GPIO15)
|
|
* ``0x04`` - GPIO4
|
|
* ``0x08`` - GPIO2
|
|
* ``0x10`` - GPIO0
|
|
* ``0x20`` - MTDI (GPIO12)
|
|
|
|
See `boot_mode.h <https://github.com/espressif/esp-idf/blob/1cb31e50943bb757966ca91ed7f4852692a5b0ed/components/soc/esp32/include/soc/boot_mode.h>`_ for more information.
|
|
|
|
See ``System#BootMode`` event to access the boot strap pin values.
|
|
|
|
|
|
|
|
Pins used for RMII Ethernet PHY
|
|
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
|
|
|
|
.. include:: ../Reference/Ethernet_PHY_ESP32.rst
|