Texas Instruments TMS320C6747 DSP Benutzerhandbuch
2.2
USB1 Module Open Host Controller Interface Functionality
2.2.1
OHCI Controller Overview
2.3
USB1 Module Differences From OHCI Specification for USB
2.3.1
Power Switching Output Pins Not Supported
2.3.2
Overcurrent Protection Input Pins Not Supported
2.3.3
No Ownership Change Interrupt
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Architecture
The Open HCI—Open Host Controller Interface Specification for USB, Release 1.0a defines a set of
registers and data structures stored in system memory that control how a USB host controller interfaces to
system software. This specification, in conjunction with the Universal Serial Bus Specification Version 2.0,
defines most of the USB functionality that the USB host controller provides.
registers and data structures stored in system memory that control how a USB host controller interfaces to
system software. This specification, in conjunction with the Universal Serial Bus Specification Version 2.0,
defines most of the USB functionality that the USB host controller provides.
The OHCI Specification for USB focuses on two main aspects of the USB host controller hardware
implementation: its register set and the memory data structures that define the appearance of USB bus
activity. Other topics include interrupt generation, USB host controller state, USB frame management, and
the hardware methods used to process the lists of data structures in system memory.
implementation: its register set and the memory data structures that define the appearance of USB bus
activity. Other topics include interrupt generation, USB host controller state, USB frame management, and
the hardware methods used to process the lists of data structures in system memory.
This document does not duplicate the information presented in the OHCI Specification for USB or the USB
Specification. USB host controller users can refer to the USB Specification and the OHCI Specification for
USB for detailed discussions of USB requirements and OHCI controller operation.
Specification. USB host controller users can refer to the USB Specification and the OHCI Specification for
USB for detailed discussions of USB requirements and OHCI controller operation.
The USB1 Module OHCI compatible host controller implementation does not implement every aspect of
the functionality defined in the OHCI Specification for USB. The differences focus on power switching,
overcurrent reporting, and the OHCI ownership change interrupt. Other restrictions are imposed by the
effects of the pin multiplexing options.
the functionality defined in the OHCI Specification for USB. The differences focus on power switching,
overcurrent reporting, and the OHCI ownership change interrupt. Other restrictions are imposed by the
effects of the pin multiplexing options.
The device does not provide pins that can be controlled directly by the USB host controller OHCI port
power control features. The OHCI RHPORTSTATUS register port power control bits can be programmed
by the USB host controller driver software, but this does not have any direct effect on any VBUS switching
implemented on the board.
power control features. The OHCI RHPORTSTATUS register port power control bits can be programmed
by the USB host controller driver software, but this does not have any direct effect on any VBUS switching
implemented on the board.
You can use software control of GPIO pins or other implementation-specific control mechanisms to control
VBUS switching.
VBUS switching.
The device does not provide any pins that allow the USB host controller OHCI RHPORTSTATUS
overcurrent protection status bits to be directly controlled by external hardware.
overcurrent protection status bits to be directly controlled by external hardware.
You can use software monitoring of GPIO pins or other implementation-specific control mechanisms to
report port overcurrent information to the USB host controller driver.
report port overcurrent information to the USB host controller driver.
The USB host controller does not implement the OHCI ownership change interrupt.
SPRUFM8 – September 2008
Universal Serial Bus OHCI Host Controller
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