> For the complete documentation index, see [llms.txt](https://principiot.gitbook.io/principiot-docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://principiot.gitbook.io/principiot-docs/f7-pi/uart-peripheral-mapping.md).

# UART Peripheral Mapping

| UART Assignment | Peripheral                                        |
| --------------- | ------------------------------------------------- |
| UART 1          | Available on the expansion header                 |
| UART 2          | RX (Receiver) port                                |
| UART 3          | GPS port                                          |
| UART 4          | UART port, shared with Raspberry Pi               |
| UART 5          | VTX (Video Transmitter) port                      |
| UART 6          | Shared between Raspberry Pi and ESC telemetry pin |

## Raspberry Pi UART Connection

UART 4 is connected to the UART pins on the Raspberry Pi's GPIO header and the UART JST connector. The mapping of these pins is controlled by two solder jumpers on the bottom of the board.

By default, UART 4 will be connected directly to the Raspberry Pi's UART. This enables direct communication between the Flight Controller and the Raspberry Pi, such as for telemetry streaming.

In some applications, it may be preferred to connect the UART JST connector to only one of the Flight Controller or Raspberry Pi, or devote one of the pins of the UART to an external interface. By cutting or bridging the solder jumpers, the Flight Controller or Raspberry Pi can be exclusively connected to the UART connector.