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Roadmap says the S3 touch boards do not supply VBUS; the schematic says they do #5

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@bdbarnett

From a schematic read of the Waveshare ESP32-S3-Touch-LCD-4.3 and -7 (2026-09-04).

docs/usbif-roadmap.md (anchor repo) states in two places that these boards cannot source VBUS:

  • line 136 — "host mode on them requires a powered hub or externally powered OTG adapter, since neither switches VBUS"
  • line 155 — "The S3 boards do not switch VBUS"

Both schematics tie the Type-C VBUS pin directly to the board 5 V rail — no load switch, no current limit, no GPIO control — fed either from the UART port through an AO3401 ideal diode or from the CS8501 battery boost. So the accurate statement is that they do not switch VBUS but do source it, unconditionally, whenever the board is powered.

That is almost certainly why the unpowered hub enumerated on 2026-08-31, and it makes the difference between "needs an accessory" and "works today" for anyone reading the roadmap to plan hardware.

The unswitched, uncurrent-limited part is worth keeping as a caution: there is no over-current protection between the 5 V rail and whatever gets plugged in.

While here — a related claim of mine is stale and worth not repeating: hub support is enabled and working, per cmods/patches/usbif-04-...:33 and usbif-06-...:33 (CONFIG_USB_HOST_HUBS_SUPPORTED=y) and README:68. Any note still saying otherwise predates that fix.

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