Team meeting 25/10/2020

[wassfila]

Agenda :

• Solve the confusing situation of the Fuel Gauge
• Charging Status LED
• (feature/mcu) Look closer on Add MCU and USB-UART bridge and related components #36 and seek assistance to bring it to master
• (feature/regulator_rtc) have a common review and maybe merge Rework of RTC and regulator module #41
• state the open points that prevent the original variant from starting routing
• think of a routing strategy, how to split the routing job

[wassfila]

Fuel Gauge general discussion

• generally voltage only, not very reliable as it does not map in percentage of remaining capacity
• that's why a simple compare at one level Full/Empty would be enough
• the LTC has a function to measure the internal resistance => aging of the battery details in the datasheet
• requirement # 10 rejected at a time when LTC was not planned, then LTC functionality took over.
• The advantage of a fuel gauge is to show a measure independent from the uC
• if the uC gets involved then all options become easy, not even an LED compare would be needed, but still one LED compare can be kept to make it more reliable
• two extremes simplest and best
  • simplest, it's not about simplicity, it's more about reliability
  • it's more important to have configurable options
  • most advanced fuel gauge, RGB Led (while charging only) / ePaper monitor (low power)

Andreas :
comment about information, what can you do with it ? Can you act with it ? so recommended to automate things, the system should take care and not the use, only warn me when there is a warning and not disturb if everything is working. Usually these PCBs are in a box or built into something, still one GPIO could be added if really needed. not recommended to have on board gauge, but could be added as add on for configurable project, just not on the core board

Charging Status LED

@MantaRayDeeJay express concerns about having it running parallel to the LTC chip, due to ground elevation / sense function.

=> TODO #44 simulation ongoing @2010019970909 with test of LED battery full status (local work could be put on a file on the repo)

• not recommended to add LED in parallel to the power as it does not necessarily means loading.

Andreas :
it's a detail, provided general concept about information.

feature MCU PR

• worked together during the meeting to figure out what the issue is, did not manage, got blocked
• Add MCU and USB-UART bridge and related components #36 blocked with MCU branch - ERC error #43 help wanted, error on github PR job not seen on local ERC (file missing)

feature RTC rework

• Rework of RTC and regulator module #41 main different cut off in regulators not in RTC sheet
• some review findings documented in Rework of RTC and regulator module #41 (comment)

Next steps before routing

• hierarchical labels to be added to MCU sheet
• VBUS to be added as hierarchical label
• lots of ERC errors to solve, help needed will be done once all is in master

Routing strategy

• cannot be shared as would conflict so to be done one by one
• no parallel branches
• each work merge in master
• next branch and continue
• all components to be checked again BOM definition (which MOSFET, values,..)
• improvements on using kicad global component

Announcements

Andreas:

• important to work on announcement

• if a board variant is available, would be good to challenge the work on the public channels

• low cost version ready for reviews

• TODO provide ready pdfs for reviews to provide to @Informaticore that will post the announcement