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I2C Bus (Development Overview)

I2C 是一种分组交换串行通信协议,允许多个主设备连接到多个从属设备,每个连接只需使用2根电线。 它用于在短距离、板内通信中将低速外设 IC 连接到处理器和微控制器。

Pixhawk/PX4 支持:

  • Connecting off board components that require higher data rates than provided by a strict serial UART, such as rangefinders.
  • 与仅支持 I2C 的外围设备兼容。
  • 允许多个设备连接到单个总线(有效保护端口)。 例如,LED、指南针、测距仪等。

The page Hardware > I2C Peripherals contains information about how to use (rather than integrate) I2C peripherals and solve common setup problems.

IMUs (accelerometers/gyroscopes) should not be attached via I2C (typically the SPI bus is used). The bus is not fast enough even with a single device attached to allow vibration filtering (for instance), and the performance degrades further with every additional device on the bus.

集成 I2C 设备

Drivers should #include <drivers/device/i2c.h> and then provide an implementation of the abstract base class I2C defined in I2C.hpp for the target hardware (i.e. for NuttX here).

A small number of drivers will also need to include headers for their type of device (drv_*.h) in /src/drivers/ - e.g. drv_led.h.

To include a driver in firmware you must add the driver to the board-specific cmake file that corresponds to the target you want to build for. You can do this for a single driver:


You can also include all drivers of a particular type.



For example, you can see/search for CONFIG_DRIVERS_DISTANCE_SENSOR_LIGHTWARE_LASER_I2C in the px4_fmu-v4_default configuration.

I2C 驱动程序示例

To find I2C driver examples, search for i2c.h in /src/drivers/.

Just a few examples are: