Why is there no Serial 2?

Blue Robotics Products Flight Controllers
1

Greetings,

Quick question…I see the Navigator has 4 UART ports, Serial 1,3,4,5….why is there no serial 2? It is visible in the parameters, but no port on the Navigator. Just curious why 2 was skipped…

2

Hi @FairweatherIT -

@williangalvani can confirm, but I think Serial2 was decided to be a virtual port on the autopilot only, which allows a user to therefore configure network UDP streams to reach the autopilot as if they were a traditional serial connection?

3

The Navigator’s physical serial port numbering is based off the Raspberry Pi pins it’s connected to, and the Raspberry Pi’s TX2 and RX2 pins are used by the SDA0 and SCL0 connections to the Navigator’s EEPROM chip to make it more compliant with the Raspberry Pi HAT specification.[1]

The autopilot is “connected” to software-assigned ports, which BlueOS allows configuring to any of the valid serial connections. They default to the corresponding hardware ports where relevant, but can also be a virtual connection (e.g. to a UDP-serial link, as @tony-white suggested), or to another hardware connection like a serial device connected to one of the USB ports.

  1. I believe originally there were plans for the EEPROM to hold some useful configuration or calibration data, but I don’t think it’s currently being actively used. ↩︎