> For the complete documentation index, see [llms.txt](https://wiki.cbunmanned.com/wiki/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://wiki.cbunmanned.com/wiki/products-eol/cbu-cm405-fc-eol/female-header-f405/i2c.md).

# I2C

**I2C**

A single I2C port (Red/Yellow) is available for use with an external Compass. Internally this I2C is shared with the BMP280 Barometer.

<figure><img src="https://1886089318-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FolH18CdGEWKpuo9G8NHx%2Fuploads%2FPVetfyVU3gHCMlobnkA2%2Fimage.png?alt=media&amp;token=2bcc01f7-e909-48a3-85e7-78bc22989e4d" alt=""><figcaption></figcaption></figure>