USB 1.x has two defined specifications for the host controller.
One was formulated by Intel, and is referred to as UHCI (Universal Host Controller Interface). Computers with an Intel chipset are equipped with UHCI hosts.
The other was formulated by Microsoft, Compaq, and National Semiconductor, and is referred to as OHCI (Open Host Controller Interface). OHCI chips are available from various vendors including NEC, and products implemented with custom NEC chips are widely available from a number of manufacturers.
USB 2.0 has one defined specification for the host controller. The specification was formulated by Intel, and is referred to as EHCI (Enhanced Host Controller Interface). USB 2.0 host controllers are implemented by integrating an EHCI chip and a USB 1.x host controller chip into a single controller chip. NEC offers host controllers that combine EHCI and OHCI in a single package.
USB 2.0 Host Controller Specifications
- USB Host controller : 2 OHCI Controller + 1 EHCI Controller
- USB Interface : 2 to 5 downstream ports
- PCI Interface : 32 bit 33 MHz
- PCI Interface : CLKRUN#Support
- PCI ACPI : Support
- Legacy function : Support
- Package : 160 L-QFP, 176 FPBGA
The chip is used in peripheral device development kits available from the USB-IF.