qfsae / pcb Goto Github PK

We need a centralized area for tutorials, template usage, and general information related to our workflow. I propose instead of using a team-wide wiki we use the Github wiki feature.

External Altium documentation is useful at times but can also be very obscure and explained poorly. We may want to consider adding some direct documentation for common scenarios or tools within altium.

Some examples of pages that might be good to have:

• installing altium
• parts libraries (including celestial)
• using the project template
• project flow from start to finish (contributing new designs?)
• using git for hardware
• how to use DRC checking
• how to route differential pairs
• multi-page schematics, ports, etc.

• Add 100 nF decoupling capacitor to power input of reference design.

Re-import 2-layer 1-oz JLCSMT design rules to Arduino Uno shield template.

The submodule locks the library version but the celestial library is always being updated and thus it is sensible to have team members clone it from the main celestial repo directly.

Some onboarding projects ended up merged into the root folder of the repo instead of onboarding/Q21 for convenience.

Just move them into the proper folder to keep everything nice and clean.

DOD:

• Has QFSAE logo in addition to the existing information

Below is a list of errors I made on the steering design that we should fix in a future iteration.

• CAN bus switchable termination. Both throws of the switch are connected to CAN_P meaning it effectively does nothing. This was a net naming error and one of the labels should be changed to CAN_N.
• Power sequencing.
  • The regulators currently feed directly into one another without any kind of protection. We should add some kind of PMIC so that we don't have backpowering. Ie. when I plug in 3.3 V only, the 5V and 12 V LEDs should not turn on. This is confusing behaviour and makes you think it's working when it is not.
  • Also, both the CAN transceivers and Neopixels depend on a 5V power supply. I think it would make sense to send a PGOOD signal to the MCU so we know that are actually properly powered. This has caused a lot of grief in the past since you can run the MCU with just 3.3 V but the CAN ends up being broken. Alternatively, we could have some kind of power AND gate that only feeds power to the MCU if the 5V is also available.
• The button silkscreen is mislabeled, the text shown on the physical pcb does not match the schematic net names.
• New feature to consider: Directly integrating the debugger schematic into the steering wheel so we can do everything on one PCB.
• Break out extra IO on the MCU to a pin header so we have it for general use. Sometimes it is handy for debugging purposes. Also can save our bacon if we end up assigning the wrong pinout somewhere in our primary connectors.
• Toss the Queen's racing logo on the board!
• Make the 12 -> 5V voltage regulator a switching buck converter. We used linear in the first iteration due to lack of time / fears of it not working. It works as is but it is very wasteful on the power front and produces unneeded heat. Considering we are going through a current limited quick release connector in the steering assembly, I think it is worth doing this. Also what you are going to see far more often in industry. (Tip: many switching regulators have a PGOOD signal we could use for detecting the presence of 5V as well)

New Version of the Transceiver Reference Design

• SW controlled bus termination option

Things that should be ignored now:

• Gerber Files
• *.htm files and other Altium junk output
• History Folder
• Project outputs
• Project logs

Note that some of these items are already being ignored in our current file but it seems that they are still showing up in some projects.

Create C header file for V0 Pinmap of VCU