| 摘要 |
A USB (Universal Serial Bus) controller technique for implementing OTG (On-The-Go) functionality is provided. The device may have an EHCI (Enhanced Host Controller Interface) compliant host control unit, and an OTG control unit to implement an OTG state machine partly in hardware and partly in software. The OTG control unit may have an OTG control register and an OTG status register which are accessible by software. Further, the USB controller device may have a device control unit to implement device functionality and a port multiplexer to assign a physical port to either the host or the device control unit. The OTG control unit may be comprised in the port multiplexer. Further, a software driver may read the OTG status register in response to receiving an interrupt from the USB controller device, and write to the OTG control register to force the USB controller device to change its OTG state. |
