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USB 2.0 Device Controller
The USB is a 4-wire serial bus that supports communication between a host and a number (127 max) of peripherals. The host controller allocates the USB bandwidth to attached devices through a token based protocol.
The bus supports hot plugging, unplugging, and dynamic configuration of the devices. All transactions are initiated by the host controller. The LPC2141/42/44/46/48 is equipped with a USB device controller that enables
12 Mbit/s data exchange with a USB host controller. It consists of a register interface, serial interface engine, endpoint buffer memory and DMA controller. The serial interface engine decodes the USB data stream and writes data to the appropriate end point buffer memory.
The status of a completed USB transfer or error condition is indicated via status registers. An interrupt is also generated if enabled. A DMA controller (available in LPC2146/48 only) can transfer data between an endpoint buffer and the USB RAM.
History:
The logo of the USB device also has its own history. Not so many people know that the USB logo was in development for several months. Today we can see the final design of the USB logo.
- 1994 - Seven companies united to begin the development of USB.
- 1995 - 340 companies formed the USB Implementation Forum.
- 1996 - More than five hundred USB products were already developing around the world.
- 1997 - USB Implementation Forum became richer with 60 more companies.
- 1998 - USB becomes the most popular technology on the market of electronics.
- 2000 - The introduction of USB 2.0. Today it represents the most widely used USB device.
- 2005 - USB becomes wireless.
