NXP Semiconductors freescale K51 Series Reference Manual

The host initiates transactions to specific peripherals, while the device responds to controltransactions. The device sends and receives data to and from the host using a standardUSB data format. USB 2.0 full-speed /low-speed peripherals operate at 12Mb/s or 1.5Mb/s.For additional information, refer to the USB 2.0 specification.External HubRootHubUSB CableUSB CableUSB CableExternal HubUSB PeripheralsHost PCHostSoftwareUSB CablesFigure 43-1. Example USB 2.0 System Configuration43.1.2 USB On-The-GoUSB (Universal Serial Bus) is a popular standard for connecting peripherals and portableconsumer electronic devices such as digital cameras and hand-held computers to hostPCs. The On-The-Go (OTG) Supplement to the USB Specification extends USB to peer-to-peer application. Using USB OTG technology consumer electronics, peripherals andportable devices can connect to each other (for example, a digital camera can connectdirectly to a printer, or a keyboard can connect to a Personal Digital Assistant) toexchange data.With the USB On-The-Go product, you can develop a fully USB-compliant peripheraldevice that can also assume the role of a USB host. Software determines the role of thedevice based on hardware signals, and then initializes the device in the appropriate modeof operation (host or peripheral) based on how it is connected. After connecting thedevices can negotiate using the OTG protocols to assume the role of host or peripheralbased on the task to be accomplished.For additional information, refer to the On-The-Go Supplement to the USB 2.0Specification.IntroductionK51 Sub-Family Reference Manual, Rev. 6, Nov 20111052 Freescale Semiconductor, Inc.