Design Status and Open Review Items
Current status — 2026-06-25
Goal: Xiaomi 8 Type-C OTG Hub with HUB/FLASH mode switch, USB2517 hub, RTL8153B Ethernet, external 5V input, downstream VBUS switching, and board files suitable for manufacturing.
Completed so far
- Schematic connectivity was reduced to a clean ERC state in prior review passes.
- J1 phone Type-C CC switching was implemented with a manual toggle switch and 5.1kΩ Rd resistors.
- PCB outline remains 100 mm × 100 mm.
- Stackup was changed from 4 layers to Standard 6 Layer to improve escape routing.
- Default fine routing was reduced to 0.08 mm trace width / 0.075 mm minimum trace width.
- Old partial routing around U13/U1 and +3V3 was removed to avoid stale broken traces.
- U1/Y1/D1/U10/U13 region was reworked multiple times while preserving board-edge connectors and switches.
- Y1 was moved close to U1 CLKIN and D1/U10/U13 were repositioned to improve USB escape paths.
Current manufacturing blocker
The PCB is not ready for manufacturing export.
Latest route pre-check still reports blocking items:
- R21 P1 / PHONE_VBUS_SENSE blocked
- U1 USBDN2_DM/DP differential pair blocked
- U1 USBDN3_DM/DP differential pair blocked
- U1 XTAL1/CLKIN blocked
A direct U1 rotation attempt timed out and did not clear the warnings. The persistent issue indicates the USB2517 pin escape geometry around U1 is still not compatible with the current local placement/routing constraints.
Platform blocker
Flux still reports an active working thread / auto-layout job:
- Thread:
e5492cf2-8c49-44af-9743-515eb85dd031
- Status:
working
Because this job remains active, a new auto-route job cannot be started from the agent.
Required next action before production export
- In the Flux UI, stop/cancel the stale working auto-layout/route task.
- Manually inspect the U1 USB2517 footprint orientation and pin escape direction.
- If U1 cannot escape cleanly, rotate U1 deliberately and re-place all USB2517 local parts around that orientation rather than only moving neighbors.
- Re-run route pre-check until it reports no blocking anomalies.
- Run auto-route only after pre-check is clean.
- Export Gerber/BOM/Pick-and-Place/STEP only after DRC confirms zero airwires and no blocking manufacturing errors.
Do not export yet
Gerber, BOM, and pick-and-place files should not be treated as production-ready until routing DRC is clean. Exporting now would create a manufacturing package for an electrically incomplete PCB.