Hardware/Pixhawk Dev Call: July 30, 2019

Agenda:

  • Pixhawk Autopilot Bus (PAB)
    • Number of connectors
    • Interfaces and pinout
  • Choice of connectors
    • Hobby
    • Consumer
    • Industrial
  • Pixhawk Payload Bus (PPB)
    • Community feedback
    • Specification

Dial-in:

Join Zoom Meeting

One tap mobile
+14086380968,567710856# US (San Jose)
+16468769923,567710856# US (New York)

Dial by your location
+1 408 638 0968 US (San Jose)
+1 646 876 9923 US (New York)
+1 669 900 6833 US (San Jose)
Meeting ID: 567 710 856

Find your local number: https://zoom.us/u/aetSYKbiMF

Meeting Notes

Introduction

  • ModalAI gave introduction to their flight controller based on FMUv5X
  • FMUv5X testing is in progress (ModalAI, PX4 and Auterion)
    • Hardware validation
    • Drivers for new sensors

PAB

  • Q: Several DF40 connectors on SOM? Are there concerns with this configuration?
    • ST, NXP and others have several DF40 connectors on the boards and have reliable hardware
  • Proposal: Define signals for second connector which might be introduced later in conjunction with a larger board.
    • (Ray Stits) Better mechanical stability with two connectors
    • Continue with one connector since it is not clear what signals would go onto the second connector

Signals and pinout

  • Q: How many ground pins?
    • (Lorenz) Current connector pinout has 8 free pins that could be used for ground. Would that be enough?
    • (Ray Stits) Ground pins should be colocated with power supplies and close to high speed interfaces
    • AI Ray: Follow up with recommendation for number of ground pins and pin assignment for PAB.
  • Q: Continue design with a single connector with all important interfaces and lock down the pinout on the next call?
    • SOM: If you don’t bring out every interface, someone will come out short in a later stage and have not the feature he wants/needs. This is problematic for a standardization since people miss their essential features.
    • New modules should be compatible with old base boards. Adjusted base board designs could then follow in a later stage and reduce development costs.
    • AI for community: List high-level functionality (e.g. UART with flow control, number of CAN interfaces) in discuss, if possible with pin assignment.
  • Adding new features (e.g. for H7) is easier with larger SOM footprint. This is more relevant for more capable MCUs with higher pin count (e.g higher-end NXP chips)
    • AI for community: Add use-case for this hardware (bus speeds and application) in discuss.
  • Create revision with two connectors for next week and leave 20 reserved pins in groups.

Connectors for peripherals

  • We address different market sectors with this standard.
  • Q: Do we need categorizations for different market sectors? Specify several connector types in the standard?
    • Already recognized in the document with connector options
    • Feedback on JST GH: even with proper source and tooling there have been issues, pins coming out of the housing and pins removed when pulled in certain directions.
    • In the standard, JST GH connectors are not recommended for larger drones and industrial use-cases
    • Agreement to specify alternative.
  • What connector could we standardize?
    • Molex Automotive Mini50 (cheap, easy to crimp and robust)
    • AI for community: Add connector options to the document.
    • So far there have been various proposals, but real qualification is missing.
    • Focus first on SOM and enable community to select their peripherals connector themselves. Key advantage of SOM based Pixhawk design, doing it together is difficult and dilute efforts.
      • First: Nail standardization on SOM and PAB including manufacturing and temperature calibration.
      • Second: Discuss standardization of peripheral connectors after the designs have evolved.
  • Interoperability between FC and peripherals is not to much of an issue for industrial drones since the manufacturer can design accordingly.
    • Using COTS is important for the industry, also for industrial applications
  • Steps to move forward on this topic:
    • Discuss requirements and status quo for QA process and temperature calibration
    • Discuss how to take a product to market
  • AI Michael: Take a pass and regroup the Pixhawk standardization document.

PPB

  • Define connector that goes from the base board to the payload port.
  • Focus on requirements for this connector.
  • Do we need a flexible solution to allow different mounting designs?

Action Items

  • Ray: Follow up with recommendation for number of ground pins and pin assignment for PAB.
  • Community: List high-level functionality (e.g. UART with flow control, number of CAN interfaces) in discuss, if possible with pin assignment.
  • Community: Add use-case for Pixhawk hardware (including interfaces and bus speeds) in discuss.
  • Community: Add connector options for peripheral interfaces to the document.
  • Michael: Take a pass and regroup the Pixhawk standardization document.