Universal USB buses are a popular personal computer interface. They allow serial connection of various devices up to 127 units. Universal USB buses support the function of connecting / disconnecting devices without turning off the power of the personal computer. In this case, the connected devices can be powered directly via the USB interface, which eliminates the need to use additional power supplies. This article will discuss a device such as a USB controller. We will consider its purpose, technical characteristics and types.
What is a USB controller for?
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For the USB1.1 specification, two types of such devices are developed. So for Intel USB1.0, USB-controllers such as UHCI and OHCI were developed. The difference between these devices is only in the method of access to the registers. In the first case, the registers are structurally located in the space of system ports responsible for input-output of information, and in the second, they are located in the memory section of a personal computer. The OHCI type USB controller is considered more intelligent than the UHCI type. This advantage lies in its ability to free the main processor from the need to perform routine operations associated with transferring data via USB buses. Both controllers use 32-bit addressing.USB2.0 USB EHCI. (480 /). USB1.1 .
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