USB Learning 1: What are the differences between uhci OHCI and EHCI?

1. uhci ohci ehci they are all host controller specifications
OHCI is mainly for USB chips on non-PC systems and PC boards with sishe Ali chipset
uhci is mostly I USB controller chips on ntel and via boards . the hardware circuit of uhci is simpler than that of OHCI. The cost is the highest, but the drive is complex . However, they are all from USB1.1 specifications .
EHCI is developed by several vendors such as Intel and is compatible with OHCI uhci complies with the USB2.0 specification .
USB specifications are defined at the register level, but each vendor may have its own dedicated registers.

2.
Uhci (Universal Host Controller Interface): Intel uses a hardware instance of the USB 1.1 master controller (host controller) on its chipset.
EHCI (enhanced Host Controller Interface): The standard interface of the USB 2.0 master controller.
OHCI (Open host controller inferface): a standard not only for the master controller interface for USB, but also for USB, 1394, or more ). It mainly follows the CSR (configuration space register) Standard (another standard, haha ). Is the standard that other vendors follow when designing USB host controller, such as via, NEC, Ali, including NVIDIA.
Uhci and OHCI have different hardware implementation and access to the underlying software, but both of them are completely (in fact they are somewhat insufficient) support the USB Host Controller requirements in USB 1.1 specification.
Similarly, EHCI is a hardware design that meets the requirements of USB Host Controller (high speed) in USB 2.0 specification.

USB is widely supported since Win98, whether it is uhci or OHCI. However, Ms supports (or EHCI) from Win2k SP4 and WINXP SP1. The true support here refers to the EHCI driver provided by the system without the need for a third-party driver.Program.

Apple's arm is too high, and the USB 2.0 and interfaces have been supported on Mac machines. The above host controller must be the OHCI standard.