gokul/usb3-sd-hub

Engineering draft: four-layer, computer-powered USB 3 hub with one USB-C host socket, two USB-C and two USB-A accessory sockets, and a full-size SD slot. Board and three schematic previews are available. Routing and production checks are incomplete; not fabrication ready.

Version
0.1.5
License
MIT
Stars
0

verification/POWER-DECISION.md

PCBPCB preview for verification/POWER-DECISION.md
SchematicSchematic preview for verification/POWER-DECISION.md
# Power arrangement

The user selected computer power only on 2026-10-11. Do not add an extra charger input. Keep one upstream USB-C receptacle, two downstream USB-C ports, two downstream USB-A ports and the full-size SD socket. The upstream port is a power sink; no host charging or USB Power Delivery source function is intended.

The hub, internal SD reader and peripherals share the computer's available current. Some combinations may not work, which the user accepted. Do not advertise compatibility with every host or simultaneous full-power use of every port.

This decision does not by itself validate USB power compliance. Before release, verify current before enumeration, USB 2 versus USB 3 operation, the host's Type-C current advertisement, suspend current, inrush, voltage drop and overload recovery. The hub and reader must be configured consistently for bus-powered operation. The current-limit resistors and the populated memory components are not a substitute for this validation.

Source reference: [Microchip USB2642 datasheet DS00001578F](https://www.microchip.com/en-us/product/usb2642), section 7.4.2.7. The reader's default memory configuration also needs review before programming. No validated programming image is supplied.