fly316/PX4-Autopilot
7
0
Fork 0
mirror of https://gitee.com/mirrors_PX4/PX4-Autopilot.git synced 2026-11-03 03:41:35 +08:00
Code Issues Packages Projects Releases Wiki Activity

docs: auto-sync metadata [skip ci]

Browse Source 
Co-Authored-By: PX4 BuildBot <bot@px4.io>
This commit is contained in:
PX4BuildBot
2026-02-11 22:43:01 +00:00
parent 01b348c86b
commit 36b5e1e1bb
374 changed files with 12147 additions and 1765 deletions
Download Patch File Download Diff File Expand all files Collapse all files
docs/en/sensor_bus/i2c_general.md
+16 -15
View File
@@ -4,9 +4,9 @@
It is recommended for:
* Connecting offboard components that require low bandwidth and low latency communication, e.g. [rangefinders](../sensor/rangefinders.md), [magnetometers](../gps_compass/magnetometer.md), [airspeed sensors](../sensor/airspeed.md) and [tachometers](../sensor/tachometers.md).
* Compatibility with peripheral devices that only support I2C.
* Allowing multiple devices to attach to a single bus, which is useful for conserving ports.
- Connecting offboard components that require low bandwidth and low latency communication, e.g. [rangefinders](../sensor/rangefinders.md), [magnetometers](../gps_compass/magnetometer.md), [airspeed sensors](../sensor/airspeed.md) and [tachometers](../sensor/tachometers.md).
- Compatibility with peripheral devices that only support I2C.
- Allowing multiple devices to attach to a single bus, which is useful for conserving ports.
I2C allows multiple master devices to connect to multiple slave devices using only 2 wires per connection (SDA, SCL).
in theory, a bus can support 128 devices, each accessed via its unique address.
@@ -15,7 +15,6 @@ in theory, a bus can support 128 devices, each accessed via its unique address.
UAVCAN would normally be preferred where higher data rates are required, and on larger vehicles where sensors are mounted further from the flight controller.
:::
## Wiring
I2C uses a pair of wires: SDA (serial data) and SCL (serial clock).
@@ -29,7 +28,6 @@ To ensure reliable communication and to reduce crosstalk it is advised to apply
![Cable twisting](../../assets/hardware/cables/i2c_jst-gh_cable.jpg)
## Checking the Bus and Device Status
A useful tool for bus analysis is [i2cdetect](../modules/modules_command.md#i2cdetect).
@@ -41,8 +39,8 @@ The tool can be run in the PX4 terminal with the following command:
```
i2cdetect -b 1
```
where the bus number is specified after `-b` parameter
where the bus number is specified after `-b` parameter
## Common problems
@@ -62,8 +60,9 @@ The bandwidth available for each device generally decreases as more devices are
If too many devices are added, it can cause transmission errors and network unreliability.
There are several ways to reduce the problem:
* Dividing the devices into groups, each with approximately the same number of devices, and connecting each group to one autopilot port
* Increase bus speed limit (usually set to 100kHz for external I2C bus)
- Dividing the devices into groups, each with approximately the same number of devices, and connecting each group to one autopilot port
- Increase bus speed limit (usually set to 100kHz for external I2C bus)
### Excessive Wiring Capacitance
@@ -71,9 +70,10 @@ The electrical capacity of bus wiring increases as more devices/wires are added.
The problem can be analyzed using an oscilloscope, where we see that the edges of SDA/SCL signals are no longer sharp.
There are several ways to reduce the problem:
* Dividing the devices into groups, each with approximately the same number of devices, and connecting each group to one autopilot port
* Using the shorter and higher quality I2C cables, see the [cable wiring page](../assembly/cable_wiring.md#i2c-cables) for details
* Separating the devices with a weak open-drain driver to smaller buses with lower capacitance by using [I2C Bus Accelerators](#i2c-bus-accelerators)
- Dividing the devices into groups, each with approximately the same number of devices, and connecting each group to one autopilot port
- Using the shorter and higher quality I2C cables, see the [cable wiring page](../assembly/cable_wiring.md#i2c-cables) for details
- Separating the devices with a weak open-drain driver to smaller buses with lower capacitance by using [I2C Bus Accelerators](#i2c-bus-accelerators)
## I2C Bus Accelerators
@@ -81,6 +81,7 @@ I2C bus accelerators are separate circuits that can be used to support longer wi
They work by physically dividing an I2C network into 2 parts and using their own transistors to amplify I2C signals.
Available accelerators include:
- [Thunderfly TFI2CEXT01](https://docs.thunderfly.cz/avionics/TFI2CEXT01/):
![I2C bus extender](../../assets/peripherals/i2c_tfi2cext/tfi2cext01a_bottom.jpg)
- This has Dronecode connectors and is hence very easy to add to a Pixhawk I2C setup.
@@ -89,7 +90,7 @@ Available accelerators include:
### I2C Level Converter function
Some I2C devices have 5V on the data lines, while the Pixhawk connector standard port expects these lines to be 3.3 V.
You can use the TFI2CEXT01 as a level converter to connect 5V devices to a Pixhawk I2C port. This feature is possible because the SCL and SDA lines of TFI2CEXT01 are 5V tolerant.
You can use the TFI2CEXT01 as a level converter to connect 5V devices to a Pixhawk I2C port. This feature is possible because the SCL and SDA lines of TFI2CEXT01 are 5V tolerant.
## I2C Address Translators
@@ -112,6 +113,6 @@ Software development for I2C devices is described in [I2C Bus (Development Overv
## Further Information
* [I2C](https://en.wikipedia.org/wiki/I%C2%B2C) (Wikipedia)
* [I2C Comparative Overview](https://learn.sparkfun.com/tutorials/i2c) (learn.sparkfun.com)
* [Driver Framework](../middleware/drivers.md)
- [I2C](https://en.wikipedia.org/wiki/I%C2%B2C) (Wikipedia)
- [I2C Comparative Overview](https://learn.sparkfun.com/tutorials/i2c) (learn.sparkfun.com)
- [Driver Framework](../middleware/drivers.md)