Telemetry / Serial Port Setup¶
This article shows how to configure the telemetry ports (aka serial ports) on the autopilot. The instructions use the Pixhawk but they apply for most autopilots.
On a Pixhawk there are a total of 5 serial ports. The default use of each port is:
- The micro USB port (aka Serial0) is used to connect to the ground station using a USB cable. This should not be connected in flight because the flight code assumes that if it is receiving power through this port that it is on the bench and some failsafes (i.e. battery failsafe) are disabled.
- Telem1 (aka Serial1) is for MAVLink communication and supports flow control. This should be used especially for high power devices (up to 1 amp) But NOT the RFD900 telemetry radio
Many non-Pixhawk style autopilots CANNOT supply even 1 amp on their port supply lines. Be sure to verify with autopilots specifications. If not specified, limit current to < 200 ma.
- Telem2 (aka Serial2) is for MAVLink communication and supports flow control.
- GPS (aka Serial3) is for connecting a GPS
- Serial 4/5 contains two serial connections on a single port. Serial4 is normally used for a second GPS. Serial5 is a debug connection.
More details of the exact pins on each port can be found here.
Set-up through the Ground Station¶
The telemetry ports can be configured through the ground station by setting the parameters listed below. If you are using the Mission Planner open the Config/Tuning | Full Parameter List page.
SERIALx_PROTOCOLparameters (where “x” is a number from 0 to 4, i.e. SERIAL1_PROTOCOL) control the protocol or purpose of the serial port. You will see on wiki pages including the Lightware Lidar page instructions for choosing the appropriate protocol.
SERIALx_BAUD(i.e. SERIAL1_BAUD) sets the baud rate or speed of the serial port.
- BRD_SER1_RTSCTS and BRD_SER2_RTSCTS parameters allow enabling or disabling flow control on Telem1 and Telem2.