esp-idf/docs/en/api-reference/peripherals/gpio/esp32h2.inc

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.. gpio-summary

The {IDF_TARGET_NAME} chip features 28 physical GPIO pins (GPIO0 ~ GPIO27). Each pin can be used as a general-purpose I/O, or to be connected to an internal peripheral signal. Through GPIO matrix and IO MUX, peripheral input signals can be from any IO pins, and peripheral output signals can be routed to any IO pins. Together these modules provide highly configurable I/O. For more details, see *{IDF_TARGET_NAME} Technical Reference Manual* > *IO MUX and GPIO Matrix (GPIO, IO_MUX)* [`PDF <{IDF_TARGET_TRM_EN_URL}#iomuxgpio>`__].

The table below provides more information on pin usage, and please note the comments in the table for GPIOs with restrictions.

.. list-table::
    :header-rows: 1
    :widths: 8 12 20

    * - GPIO
      - Analog Function
      - Comments

    * - GPIO0
      -
      -

    * - GPIO1
      - ADC1_CH0
      -

    * - GPIO2
      - ADC1_CH1
      - Strapping pin

    * - GPIO3
      - ADC1_CH2
      - Strapping pin

    * - GPIO4
      - ADC1_CH3
      -

    * - GPIO5
      - ADC1_CH4
      -

    * - GPIO6
      -
      -

    * - GPIO7
      -
      -

    * - GPIO8
      -
      - Strapping pin

    * - GPIO9
      -
      - Strapping pin

    * - GPIO10
      - Analog comparator reference voltage
      -

    * - GPIO11
      - Analog comparator input (non-inverting)
      -

    * - GPIO12
      -
      -

    * - GPIO13
      -
      -

    * - GPIO14
      -
      -

    * - GPIO15
      -
      - SPI0/1

    * - GPIO16
      -
      - SPI0/1

    * - GPIO17
      -
      - SPI0/1

    * - GPIO18
      -
      - SPI0/1

    * - GPIO19
      -
      - SPI0/1

    * - GPIO20
      -
      - SPI0/1

    * - GPIO21
      -
      - SPI0/1

    * - GPIO22
      -
      -

    * - GPIO23
      -
      -

    * - GPIO24
      -
      -

    * - GPIO25
      -
      - Strapping pin

    * - GPIO26
      -
      - USB-JTAG

    * - GPIO27
      -
      - USB-JTAG

.. note::

    - Strapping pin: GPIO2, GPIO3, GPIO8, GPIO9, and GPIO25 are strapping pins. For more infomation, please refer to `ESP32H2 datasheet <https://www.espressif.com/sites/default/files/documentation/esp32h2_datasheet_en.pdf>`_.
	  - SPI0/1: GPIO15-21 are usually used for SPI flash and not recommended for other uses.
	  - USB-Serial-JTAG: GPIO 26 and 27 are used by USB-Serial-JTAG by default. In order to use them as GPIOs, USB-Serial-JTAG will be disabled by the drivers.
    - For chip variants with an SiP flash built in, GPIO15 ~ GPIO21 are dedicated to connecting the SiP flash and are not fan-out to the external pins. In addition, GPIO6 ~ GPIO7 are also not fan-out to the external pins. In conclusion, only GPIO0~ GPIO5, GPIO8~ GPIO14, GPIO22~ GPIO27 are available to users.
    - For chip variant without SiP flash, apart from the flash IOs mentioned above, GPIO22 is not fan-out to the external pin, thus they're not available to users.

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