68 lines
2.0 KiB
ReStructuredText
68 lines
2.0 KiB
ReStructuredText
.. _i2c_api:
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Inter-Integrated Circuit (I2C) Bus
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##################################
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Overview
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********
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.. note::
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The terminology used in Zephyr I2C APIs follows that of the
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`NXP I2C Bus Specification Rev 7.0 <i2c-specification_>`_. These changed
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from previous revisions as of its release October 1, 2021.
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`I2C`_ (Inter-Integrated Circuit, pronounced "eye
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squared see") is a commonly-used two-signal shared peripheral interface
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bus. Many system-on-chip solutions provide controllers that communicate
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on an I2C bus. Devices on the bus can operate in two roles: as a
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"controller" that initiates transactions and controls the clock, or as a
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"target" that responds to transaction commands. A I2C controller on a
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given SoC will generally support the controller role, and some will also
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support the target mode. Zephyr has API for both roles.
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.. _i2c-controller-api:
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I2C Controller API
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==================
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Zephyr's I2C controller API is used when an I2C peripheral controls the bus,
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in particularly the start and stop conditions and the clock. This is
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the most common mode, used to interact with I2C devices like sensors and
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serial memory.
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This API is supported in all in-tree I2C peripheral drivers and is
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considered stable.
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.. _i2c-target-api:
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I2C Target API
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==============
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Zephyr's I2C target API is used when an I2C peripheral responds to
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transactions initiated by a different controller on the bus. It might
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be used for a Zephyr application with transducer roles that are
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controlled by another device such as a host processor.
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This API is supported in very few in-tree I2C peripheral drivers. The
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API is considered experimental, as it is not compatible with the
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capabilities of all I2C peripherals supported in controller mode.
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Configuration Options
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*********************
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Related configuration options:
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* :kconfig:option:`CONFIG_I2C`
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API Reference
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*************
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.. doxygengroup:: i2c_interface
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.. _i2c-specification:
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https://www.nxp.com/docs/en/user-guide/UM10204.pdf
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.. _I2C: i2c-specification_
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