0001 .. include:: <isonum.txt>
0002
0003 ============
0004 Introduction
0005 ============
0006
0007 The main purpose of the Industrial I/O subsystem (IIO) is to provide support
0008 for devices that in some sense perform either
0009 analog-to-digital conversion (ADC) or digital-to-analog conversion (DAC)
0010 or both. The aim is to fill the gap between the somewhat similar hwmon and
0011 :doc:`input <../input>` subsystems. Hwmon is directed at low sample rate
0012 sensors used to monitor and control the system itself, like fan speed control
0013 or temperature measurement. :doc:`Input <../input>` is, as its name suggests,
0014 focused on human interaction input devices (keyboard, mouse, touchscreen).
0015 In some cases there is considerable overlap between these and IIO.
0016
0017 Devices that fall into this category include:
0018
0019 * analog to digital converters (ADCs)
0020 * accelerometers
0021 * capacitance to digital converters (CDCs)
0022 * digital to analog converters (DACs)
0023 * gyroscopes
0024 * inertial measurement units (IMUs)
0025 * color and light sensors
0026 * magnetometers
0027 * pressure sensors
0028 * proximity sensors
0029 * temperature sensors
0030
0031 Usually these sensors are connected via :doc:`SPI <../spi>` or
0032 :doc:`I2C <../i2c>`. A common use case of the sensors devices is to have
0033 combined functionality (e.g. light plus proximity sensor).
