Hattix.co.uk PC Hardware Collection
     
  Other Hardware
Internal USB 2.0 Hub
These cool little things were £1.95 from China. They come with a half-populated cable to fit on an internal USB header, and give you two headers. If you buy two of them, you can rewire the plug for the motherboard header, and run both of them off one header, as each header gives two USB connections. In its most basic form, one of these takes connectivity for two USB ports and turns it into four USB ports, while leaving a row of pins on the motherboard unused (but inaccessible without modifying the cable).

In an era where USB 2.0 is used for basic connectivity, these can add in enough connectivity for smartphone cables, keyboards, mice, WiFi, BlueTooth adapters... One niggle, and this is unfair with how cheap they are, is that they're bus-powered.

The ASIC in use is the GL850G by Genesys Logic, Inc. in its SSOP-28 packaging. That link there goes to locally hosted manufacturer documentation. The ASIC can control a green and amber LED natively for port status, but none is provisioned on this board (as it's intended for internal use).

At the heart of the GL850G is the RISC microprocessor, which has 2K firmware ROM and 64 bytes RAM. It runs at 6 MIPS from the USB base 12 MHz clock, and is employed to decode the USB command from the host and prepare the response to the host. It can also do GPIO and read an external EEPROM, which can configure a custom USB ID. One pin on the package serves to switch the ASIC between self-powered hub and bus-powered hub mode. In self-powered mode, the chip is still powered itself by the host USB 5V (or can be, it doesn't actually care), but will handle power assignment itself, with the assumption that each port has 500 mA available. In bus-powered mode, it will pass power requirement through to the host.

The date code on this says it was produced in week 50, 2019 (it was ordered in week 4, 2020!) and the package code is a "Y" which is likely newer than the specification document: It should be G for green package (mandated by EU) and N for normal package.

Like almost all USB hub controllers, it does not power the output ports itself, the PCB is meant to route the 5V rail. This means the downstream ports are unsuitable for charging modern smartphones. Variants are available which will accept a 4 pin or SATA-style power connector and so be self-powered.
     
Script by dutches   © 2002-2018 Hattix.co.uk. All rocks deserved. Creative Commons LicenseHattix hardware images are licensed under a Creative Commons Attribution 2.0 UK: England & Wales License except where otherwise stated.