Date

25 Jan 2023

Attendees

Goals

Review power, backplane, sensor schematics

General Notes

Updates/changes to requirements for each module:

Now responsible for ESD/overcurrent/reverse-polarity protection on the module.
- Overcurrent protection is to be accomplished by a polyfuse (aka PTC or self-healing fuse) in series with a standard fast-blow fuse on each power rail, appropriately sized to the expected load of the module. Polyfuse should be rated to trip before the other fuse.
- Reverse polarity protection is to be accomplished with a low-resistance FET. See Texas Instruments SLVA139 Figure 3 (Link) for more details.
- ESD protection at a minimum on all out-of-board connectors, preferably also including internal-to-board protections.
  - Mentioned multi-channel WSON EMI filter with ESD protection: TPD8F003DQDR (Datasheet)
  - To further mitigate short/shock risk, where possible replace male headers with shrouded female headers
  - For further information on protecting data/signal lines from ESD, see Texas Instrument's 2022 System-Level ESD Protection Guide (Link)
All modules using Vbat must design to withstand battery voltages up to 12v
LEDs on the backplane (interfaced through 30-pin connector) are to be operated at 3.3v, although they are 5v tolerant.
Any LEDs on the module (including those for ethernet) must be toggleable by the module's MCU. Recommend using Vishay SI2301CDS-T1-GE3 (Link)
- Modules are advised to take any other ground-exclusive, high-load components and place them on switching as well, to be deactivated when the umbilical is removed.
Modules must be designed so that they can be assembled using JLCPCB's single-sided, "Economic" assembly option
- In addition to one-sided assembly, places some restrictions on minimum pin spacing, package type, etc.
  - Minimum Package: 0402
  - Minimum IC Pin Spacing: 0.5mm
  - Minimum BGA Spacing: 0.4mm
- Any parts not available for economic PCB will be marked as such on JLC's part library.
- No through-hole components should be assembled by JLCPCB
- https://jlcpcb.com/capabilities/pcb-assembly-capabilities
Any programming resistors (such as those used on Ethernet) need to be assembled in a way that the module ships in a determinate, ready-to-use configuration
- In other words, do not have both a pull-up and a pull-down resistor on the same pin

All modules will have an STM32 GPIO check in the near future, to ensure the proper pins are being used for certain signals

The software team requests, if possible, putting the Wiznet and the memory IC on 2 different SPI busses
Multiple i2C busses can be used for ease of routing if desired

Battery protection circuitry, as well as the power changeover circuitry, is now moved to the backplane.

This potentially includes a battery protection IC. See XB8089D as a 1S reference (Datasheet)

All modules must update the ethernet layout to include the 33R EMI-reducing resistors called out in the W5500 reference design.

May be removed/replaced with 0R in the future.

Discussion items

Item	Who	Notes

Autopilot Module	Ben Hyman (RIT Student)	Updates: Confirmed Vocore pin state is input Schematic 99% done Came up with a few more changes today. Have LED1 connect to Vocore power out to confirm power on 220u brownout capacitors Ready to be reviewed Layout ~80% done All components are placed and most routed. Mainly just need to route backplane connector TODOs: Schematic: Add brownout capacitors Connect vocore 3v3 out to backplane LED1 instead of its own LED as it is currently Layout: Finish routing Run DRC and deal with errors
Sensor Module Updates	Mary Dertinger (RIT Student) lewiz	Updates: All sensor schematics done. STM32 and Backplane interface almost done. TODOS: Review schematics with team Start layout!

Item

Who

Notes

Autopilot Module

Ben Hyman (RIT Student)

Updates:

Confirmed Vocore pin state is input
Schematic 99% done
- Came up with a few more changes today.
  - Have LED1 connect to Vocore power out to confirm power on
  - 220u brownout capacitors
- Ready to be reviewed
Layout ~80% done
- All components are placed and most routed. Mainly just need to route backplane connector

TODOs:

Schematic:
- Add brownout capacitors
- Connect vocore 3v3 out to backplane LED1 instead of its own LED as it is currently
Layout:
- Finish routing
- Run DRC and deal with errors

Sensor Module Updates

Mary Dertinger (RIT Student) lewiz

Updates:

All sensor schematics done.
STM32 and Backplane interface almost done.

TODOS:

Review schematics with team
Start layout!

Attendees

Goals

General Notes

Discussion items

Action items

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