Intro

• Who

  • EngineerComponent Library, Layout: Meghan Dang

  • ManagerArchitect, Component Selection, Schematic, Reviewer, Schematic: Daniel Puratich

  • Firmware: Derek Tang Nathan Green

  • Advisors: Aidan Bowers, Kevin Li

• Why

  • we want to space ESCs out, have a higher datarate, and less harness complexiycomplexity

  • CAN supported ESCs exist but more expensive and not what we have alr, we like what we have right now

  • DSHOT is already a digital protcol that’s busable

    • single ended

    • prone to ground loops and common mode SI

    • 100mil hdrs into pixhawk and from ESC

• What

  • board solders onto the ESCs both DSHOT data pins that has a JST CAN connector to pixhawk

  • the firmware and hardware will not implement an ESC, we will continue to rely on COTS for this assuming the COTS solution features a standard DSHOT 100mil pitch connection (as the APD ESCs we have right now do)

  • firmware wise this is a CAN to bidirectional DSHOT adapter.

• How:

  • small STM and a CAN transcievertransceiver, may require a little LDO for power, see below for design procedure

• When

  • Starting Early June 2024

• Where

  • https://warg.365.altium.com/designs/9504A71D-9B2B-4328-B339-C3EBBC2F7DF1#design

Table of Contents

...

System Background/Research

most information pulled from 2024 System Architecture

Pixhawk

link to pixhawk docu for CAN transcievr

https://holybro.com/collections/autopilot-flight-controllers/products/pixhawk-6x

https://docs.holybro.com/autopilot/pixhawk-6x/technical-specification

https://ardupilot.org/plane/docs/common-holybro-pixhawk6X.html

APD ESC

note that other DSHOT supporting ESCs are similar pinout wise.

dshot has a sig in, a sig out, and a GND pin here

https://powerdrives.net/120f3 sales page

https://docs.powerdrives.net/products/f_series/quick-start-guide manual page

excerpt from their documentation:

...

Other Devices

• ark CAN node

  • https://github.com/ARK-Electronics/ARK_CANNODE/blob/main/Hardware/Rev%201/ARK%20CANNODE%20Rev%201%20Schematic.PDF

  • https://arkelectron.com/product/ark-cannode/

  • switched CAN termination is actually an insanely good idea for hobbiest CAN networks

Design

System Wiring Diagram

how Diagram explains this board connects to ESC and rest of the system. Other CAN nodes should be implemented similarly. Daniel Puratich is handling this diagram to help set the stage and improve on diagrams from Custom CAN Hub and concepts discussed widely.

Schematic Wise

Most detail is on this board, but kind of describes the system.

Layout Sample

This is a starting place for a simple plane example, but shows how a layout could look with a full CAN architecture. Eventually battery bay could support more CAN and reduce harnessing there, but the battery bay and avionics will be very close to eachother so they’re lower priority than the farther away stuff.

CAN Header Selection

Will follow Pixhawk Electrical Connector Standards .

copy pixhawk for MPN

input and output CAN hdr

...

100mil hdr mount onto it

Micro Selection

some STM

https://discord.com/channels/776618956638388305/1241377889035882646/1242282003018154025

LFSPXO072801 ← possible 8mhz HSE, used on the ark one, seems fine to me

CAN Transceiver Selection

• https://discord.com/channels/776618956638388305/1241377889035882646/1242282003018154025

  • copy pixhawk? kinda yea but chosen in discord and no real contest

  • no need for CANFD imo

• common mode choke

  • need to select

  • https://www.ti.com/lit/an/slla271/slla271.pdf?ts=1716408899789&ref_url=https%253A%252F%252Fwww.google.com%252F

  • SRF2012A-121YA

  • https://www.digikey.ca/en/products/detail/bourns-inc/SRF2012A-121YA/5429616

  • ACM2012-201-2P-T002

  • https://e2e.ti.com/support/isolation-group/isolation/f/isolation-forum/1166945/iso1042-q1-common-mode

...

Power Decision

• • -choke-selection-for-can-bus#:~:text=The%20inductance%20of%20the%20common,inductance%20of%20around%20100%20%C2%B5H.

  • ACT45B-101-2P-TL003

  • ACM2012-361-2P-T002

  • B82786L0104N002

  • https://product.tdk.com/en/products/selectionguide/cmf.html

    • doesnt even include CAN lmao

  • https://product.tdk.com/en/techlibrary/productoverview/automotive-cmf_can-fd.html

  • ACT1210D

  • ACT1210D-510-2P-TL00

• switched termination

  • done on ARK board with a low side FET

    • seems like a bad idea if it gets GND offset, other designs online dont show this, see below

  • https://www.analog.com/en/resources/reference-designs/circuits-from-the-lab/cn0401.html

    • https://www.analog.com/media/en/technical-documentation/data-sheets/ADM3055E-3057E.pdf

    • AQY221RV

      • https://www.digikey.ca/en/products/detail/panasonic-electric-works/AQY221R2VY/646325

  • https://www.ti.com/lit/ug/tiducf3/tiducf3.pdf

  • https://toshiba.semicon-storage.com/info/TLP175A_datasheet_en_20230525.pdf

    • https://www.digikey.ca/en/products/detail/toshiba-semiconductor-and-storage/TLP175A-TPL-E/4562829

    • commit to this one, cheaper

• high speed TVS

  • https://assets.nexperia.com/documents/data-sheet/PESD2CANFD24U-QC.pdf

    • exmpla pre nice

  • PESD2CANFD24U-QCZ

  • NUP2105LT1G

Power Decision

LM66100 for RPP

LDO to power the transciever?

how much capacitance, decent amount, same damping would be nice too lol

https://www.digikey.ca/en/products/detail/texas-instruments/TLV75533PDBVR/9356541 for LDO

Schematic High Level

Board Outline Sketch

Roughly how will system look? nah no point, see the schematic!!