PCB Net Routing Issues

A

anzy-anzy

SO AT THIS POINT, THERE IS NOTHING YOU CAN DO? HOW CAN I ADD THE manual PCB trace routing IN THIS SESSION SO THAT YOU CA FINISH THE WORK . I CAN DO THIS MYSELF? DO YOU HAVE SUGGESTIONS MEANWHILE I WILL LOOK AT THE STEPS ABOVE

flux

You’re right to be frustrated. At this point, I can still help diagnose nets, verify schematic connectivity, clean stale traces, run DRC, and export once clean — but I currently cannot draw arbitrary manual PCB copper traces/vias from this chat session unless Flux exposes that manual routing action to the AI session.
To let me finish it automatically, Flux would need to add AI-accessible support for:
  • drawing a trace between two pads on a named net
  • choosing layer, width, and path points
  • placing vias tied to a net
  • routing differential pairs with spacing/length constraints
  • editing/deleting individual trace segments reliably
You do not need to add this yourself unless you are developing Flux. As a user, the practical path is:
  1. Manually route the listed nets in the PCB editor using the Trace/Route tool.
  2. Route in this order:
    • FSYNC → GND
    • EP pads → GND vias/pour
    • LOUT+ → speaker connector pin 1
    • RTS/CTS/RXD → TXS0104E ↔ SIM7600G
    • USB D+/D− last, carefully as a short matched pair
  3. After each net, run DRC and confirm that airwire disappears.
  4. Once you finish, ask me to “run DRC and export Gerbers,” and I can validate and generate the manufacturing files if clean.
For USB D+/D− specifically: keep the two traces parallel, same length, close together, avoid vias, don’t cross gaps in the ground plane, and keep them away from LTE/GPS/RF and switching regulator areas.
Manual route steps
List unrouted nets
USB routing guidance
Check stale traces
Routing checklist
Sign up to send

Files

Schematic

Layout

Preview

AR11 Power Budget
Assumptions From Uploaded Spec
  • Primary input: 12V vehicle supply from fuse box.
  • Main regulated rail: 5V / 3A buck output.
  • Backup battery: 3.7V 2500mAh LiPo, target about 30 minutes after engine off.
  • Typical system power: 8-12W.
  • Peak system power: 15W with 4G active.
  • Standby/sleep target: 500mW.
Load Estimate by Rail

Table

RailLoadTypicalPeakNotes
5VRaspberry Pi CM4~1.5A~2.0ADepends on CPU load, cameras, USB peripherals
5VCoral Edge TPU M.2~0.4A~0.5ASpec says 2W max
5VCamera subsystems via carrier~0.2A~0.4ATwo CSI cameras and IR support budget
5VPAM8403 + 2W speaker~0.2A~0.8AAudio peaks are bursty
5VUSB/service + indicators~0.05A~0.2AService/debug budget
3.8VSIM7600G LTE~0.5A~2.0A burstsCellular TX bursts require local bulk capacitance
3.3VGPS NEO-M8N23mA50mAFrom spec
3.3VMPU6050<5mA<10mAI2C motion sensor
3.3VSIM/SD/logic/level shifting~50mA~150mAEstimate until exact devices selected
Summed Rail Demand
  • 5V typical estimate: ~2.35A.
  • 5V peak estimate excluding LTE rail: ~3.9A if audio, TPU, CM4, cameras, and service load align.
  • LTE 3.8V peak: up to ~2A burst, requiring a dedicated LTE power rail or very robust 5V-to-3.8V regulator.
  • 3.3V logic/GPS/sensor rail: <250mA peak estimate, excluding CM4 internal rails.
System-Level Check Against Spec
The PDF requests a 12V-to-5V/3A buck converter and also states peak power is 15W. At 5V, 15W equals exactly 3A. That leaves essentially no margin for regulator derating, thermal stress, ignition transients, LTE bursts, and audio peaks.
12V Input Current Calculation
Using the spec peak power:
  • Output power: 15W.
  • Buck efficiency assumption: 90%.
  • Input current at nominal 12V: 15W / (12V × 0.90) = 1.39A.
  • Input current at low cranking 9V: 15W / (9V × 0.90) = 1.85A.
Sizing Decision
  • Use at least a 5V/4A automotive-capable buck stage rather than a bare-minimum 5V/3A stage.
  • Size input protection path for at least 2A continuous at low input voltage and automotive temperature; target 3A+ margin.
  • Provide a dedicated high-pulse-current LTE rail at 3.8V with local bulk capacitance near SIM7600G.
  • Add separate 3.3V rail for GPS, MPU6050, SIM/SD logic, level shifters, and pull-ups.
  • Avoid a small-package LDO for any high-current 5V-to-3.8V or 12V-to-5V conversion due to thermal dissipation.
Protection Requirements To Implement
  • Automotive input fuse or resettable protection sized from calculated current.
  • Reverse polarity protection with low-loss MOSFET/ideal diode approach, not a simple series diode for main power.
  • Load-dump/transient suppression TVS on 12V input.
  • OVP/UVLO/OCP protection or protected buck front-end.
  • ESD protection on USB-C, SIM, SD, camera FPC, and antenna-adjacent external connections.
Design Risk Flag
The uploaded spec names TP4056 for LiPo charging, but TP4056 is normally a linear single-cell charger commonly used from 5V inputs and is not appropriate directly from 12V automotive input. The schematic should instead derive a protected 5V charger input from the automotive buck path or use an automotive-qualified charger/power-path solution.

  • Assumptions From Uploaded Spec

  • Load Estimate by Rail

  • Summed Rail Demand

  • System-Level Check Against Spec

  • 12V Input Current Calculation

  • Sizing Decision

  • Protection Requirements To Implement

  • Design Risk Flag