51 lines
2.1 KiB
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51 lines
2.1 KiB
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.. _spi:
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SPI Bus
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=======
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.. seo::
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:description: Instructions for setting up an SPI bus in ESPHome
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:image: spi.png
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:keywords: SPI
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SPI is a very common high-speed protocol for a lot of devices. The SPI bus usually consists of 4 wires:
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- **CLK**: Is used to tell the receiving device when to read data. All devices on the bus can
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share this line. Sometimes also called ``SCK``.
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- **CS** (chip select): Is used to tell the receiving device when it should listen for data. Each device has
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an individual CS line. Sometimes also called ``SS``. If the SPI bus has a single device, it's CS pin
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can usually be connected to ground to tell it that it is allways selected.
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- **MOSI** (also DIN): Is used to send data from the master (the ESP) to the receiving device. All devices on the bus can
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share this line.
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- **MISO** (also DOUT): Is used to receive data. All devices on the bus can
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share this line.
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In some cases one of **MOSI** or **MISO** do not exist as the receiving device only accepts data or sends data.
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To set up SPI devices in ESPHome, you first need to place a top-level SPI hub like below which defines what pins to
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use for the functions described above. The **CS** pins are then individually managed by the components. The ``spi:``
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component also accepts a list of buses if you want to have multiple SPI buses with your ESP (though this should
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rarely be necessary, as the SPI bus can be shared by the devices).
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.. code-block:: yaml
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# Example configuration entry
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spi:
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clk_pin: GPIO21
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mosi_pin: GPIO22
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miso_pin: GPIO23
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Configuration variables:
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------------------------
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- **clk_pin** (**Required**, :ref:`Pin Schema <config-pin_schema>`): The pin used for the clock line of the SPI bus.
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- **mosi_pin** (*Optional*, :ref:`Pin Schema <config-pin_schema>`): The pin used for the MOSI line of the SPI bus.
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- **miso_pin** (*Optional*, :ref:`Pin Schema <config-pin_schema>`): The pin used for the MISO line of the SPI bus.
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- **id** (*Optional*, :ref:`config-id`): Manually specify the ID for this SPI hub if you need multiple SPI hubs.
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See Also
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--------
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- :apiref:`spi/spi.h`
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- :ghedit:`Edit`
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