Abstract: A multi-host endpoint reflector enables a method of communication between multiple USB hosts through the USB devices connected to them, where data from one USB host is routed across the USB devices between endpoints of complimentary directions to one or more additional USB hosts. The multi-host endpoint reflector may be integrated with a USB hub controller to form a USB compound device to create a multi-host endpoint reflector hub. A USB multi-host endpoint reflector hub enables a USB OTG B device to become a host upon request by providing a data bridge between the OTG B device after it has transitioned to a host role while any other OTG A device that already is a host is not required to change its host role to a slave role. Therefore a plurality of OTG host devices may co-exist on the same interconnection system hub and communicate there between.

Abstract: A system may provide side channel access of a Universal Serial Bus (USB) device using USB streams. The system may include a USB interface with a USB device controller, an internal bus, a logical unit number (LUN) arbiter coupled between the USB controller and the internal bus, and a secondary interface coupled with the LUN arbiter. The system may include a plurality of storage devices coupled to the internal bus. The system may provide access to the storage devices via both the USB device controller and the secondary interface. The LUN arbiter may accept a plurality of USB streams (e.g., storage device access requests) from the USB device controller and at least one additional USB stream (e.g., storage device access request) from the secondary interface. The LUN arbiter may determine a priority of access between USB streams originating from the USB device controller and the secondary interface.

Abstract: A multi-host endpoint reflector enables a method of communication between multiple USB hosts through the USB devices connected to them, where data from one USB host is routed across the USB devices between endpoints of complimentary directions to one or more additional USB hosts. The multi-host endpoint reflector may be integrated with a USB hub controller to form a USB compound device to create a multi-host endpoint reflector hub. A USB multi-host endpoint reflector hub enables a USB OTG B device to become a host upon request by providing a data bridge between the OTG B device after it has transitioned to a host role while any other OTG A device that already is a host is not required to change its host role to a slave role. Therefore a plurality of OTG host devices may co-exist on the same interconnection system hub and communicate there between.

Abstract: A system may provide side channel access of a Universal Serial Bus (USB) device using USB streams. The system may include a USB interface with a USB device controller, an internal bus, a logical unit number (LUN) arbiter coupled between the USB controller and the internal bus, and a secondary interface coupled with the LUN arbiter. The system may include a plurality of storage devices coupled to the internal bus. The system may provide access to the storage devices via both the USB device controller and the secondary interface. The LUN arbiter may accept a plurality of USB streams (e.g., storage device access requests) from the USB device controller and at least one additional USB stream (e.g., storage device access request) from the secondary interface. The LUN arbiter may determine a priority of access between USB streams originating from the USB device controller and the secondary interface.

Abstract: A flexible input/output (I/O) interface allows a processing core to communicate high-speed data with a several different types of interfaces including a Direct Memory Access (DMA) interface and a streaming interface. The I/O interface includes a streaming interface for transferring streamed data from the streaming data bus to the core-processing engine, a DMA interface for transferring DMA data from the DMA data bus to the core-processing engine, and an arbiter for coordinating data transfer with the core-processing engine between the streaming interface and DMA interface. The arbiter may operate in a split-bus-mode wherein the arbiter performs the address phase for more than one channel prior to entering into the data phase. The flexible I/O interface may include a common address bus and data bus between the processing engine and the interfaces. Alternatively, a switching fabric may couple separate address and data buss of the interfaces with the processing engine.

Abstract: A flexible input/output (I/O) interface allows a processing core to communicate high-speed data with a several different types of interfaces including a Direct Memory Access (DMA) interface and a streaming interface. The I/O interface includes a streaming interface for transferring streamed data from the streaming data bus to the core-processing engine, a DMA interface for transferring DMA data from the DMA data bus to the core-processing engine, and an arbiter for coordinating data transfer with the core-processing engine between the streaming interface and DMA interface. The arbiter may operate in a split-bus-mode wherein the arbiter performs the address phase for more than one channel prior to entering into the data phase. The flexible I/O interface may include a common address bus and data bus between the processing engine and the interfaces. Alternatively, a switching fabric may couple separate address and data buss of the interfaces with the processing engine.

Abstract: The present invention is a system and method that facilitates flexible restriction of output transmissions from chosen scan test cells and reduces adverse impacts on functional components from coincidental test vector values during scan test operations. The system and method of the present invention provides the capability of masking test vector values that coincidentally trigger certain undesirable events in functional components. In one embodiment, a system and method of the present invention masks test vector values shifted into scan test cells that are coupled to bus driver enabling signals. The system and method of the of the present invention also facilitates flexible selection of which scan test cell outputs are masked and permits a scan test cell to provide a scan test vector value to an associated functional component and prevent coincidental transmission of inappropriate test vector values.

Abstract: The present invention is an ARM coprocessor power reduction system and method that turns off a coprocessor clock when an ARM system is performing THUMB state instructions. For example, the ARM coprocessor power reduction system and method of the present invention tracks signals from the ARM core periphery to determine if the ARM core is attempting to facilitate ARM state or THUMB state operations. The present invention compares the THUMB bit indicator in signals associated with each stage of an ARM pipeline and determines if the instructions are THUMB state instructions. If the instructions are THUMB state instructions the ARM coprocessor power reduction system and method of the present invention turns off the coprocessor clock. Turning off the coprocessor clock prevents the coprocessor registers from switching and consuming power.

Abstract: The present invention is a system and method that permits appropriate scan testing of internal components of an integrated circuit while reducing the number of external pins required to perform the scan testing. One embodiment of the present invention utilizes standard IEEE 1149.1 pins (e.g. TDO, TDI, TMS, TCK, etc.) to perform both boundary scan and full scan testing. A modified IEEE 1149.1 TAP controller generates signals to control the boundary scan and full scan operations. For example, a full scan cell facilitates full scan capture and shift operations when the TAP controller generates a full scan test mode signal and a full scan enable signal in response to inputs via the standard IEEE 1149.1 pins. In one example the scan enable signal is asserted when the TAP controller is in a shift state and the TAP controller's instruction register is loaded with a test mode instruction. A functional clock capture cycle is applied when the state machine of the TAP controller is in run/idle state.

Abstract: The present invention is a system and method that minimizes discarding of a pending read transaction in a peripheral component interconnect (PCI) bus architecture due to an arrival of a write request while maintaining appropriate transaction ordering. The read/write optimizing system and method of the present invention optimizes read performance by continuing to process a pending read transaction under appropriate conditions while partially performing the write request and inhibiting its completion. In one embodiment of the read/write optimizing system and method of the present invention, a write transaction is inhibited by tracking or storing an inhibited write transaction target address if a pending read transaction address is not within a range of an inhibited write transaction address. For example, a target address associated with an inhibited write transaction is temporarily latched in a write address register until a pending read transaction is completed or terminated.

Abstract: An arrangement controls an IC designed with multiple “core” circuits, such as multiple CPUs, with each core circuit including its own TAP controller. According to one example embodiment, multiple test-access port (TAP) controllers coupled to a common interface are controlled by adapting each TAP controller to receive input signals, determine if the TAP controller is enabled, and generate status signals and test signals. An output circuit responds to the TAP controllers by outputting one of the test signals respectively provided by the multiple TAP controllers, and a link module is used to maintain one of the TAP controllers enabled at a given time. The above-embodiment is useful, for example, in connection with IC applications that require an increasing number of core circuits without increasing the circuit area of the IC and/or the number of IC pins, and can be implemented to avoid changing existing structures of TAP controllers.

Abstract: An arrangement controls an IC designed with multiple “core” circuits, such as multiple CPUs, with each core circuit including its own TAP controller and with multiple TAP controllers enabled at a time. For applications typically requiring that control be transferred between such TAP controllers, one embodiment of the present invention configures a TLM-based design such that multiple TAP controllers can be simultaneously enabled. This alleviates the need to actually transfer the control from one TAP controller to the next. To maintain consistency with the IEEE JTAG recommendation, the TLM-based design is configured such that only one TAP is enabled upon reset. After reset, the TLM controls the multiply-enabled TAP controllers. Another specific example implementation is directed to a circuit control arrangement for such a multi-core IC having each TAP controller generate status and test signals in response to input signals directed to each of the multiple TAP controllers.

Abstract: An arrangement controls an IC designed with multiple “TLM'ed core” circuits, such as multiple CPUs, with each core circuit including its own TAP controller and with multiple TAP controllers enabled a time. For applications typically requiring that control be transferred between such TAP controllers of various core circuits, one embodiment of the present invention expands a multiple “TLM'ed core” circuit design without changing the IEEE JTAG specification and without requiring more scan chains per TAP'ed core. One particular example embodiment includes each of the design's multiple cores including multiple test-access port (TAP) controllers, and including an internal TLM having a TLM register adapted to store a decodable instruction and a supplemental storage circuit adapted to store a coded signal.

Abstract: A system and method that prevents address aliasing and eliminates the unnecessary clock cycle consumed by the use of a dual address cycle when using a single address cycle to transmit a target address in a computer system including target devices having addresses of different sizes, such as 32-bit and 64-bit target devices, with 32-bit and 64-bit addresses, respectively. In addition, a combination of single address cycles and dual address cycles may be used to prevent address aliasing while permitting access to the entire address spaces of the target devices. The computer system includes a bus, an initiator device coupled to the bus, a first target device coupled to the bus, and a second target device coupled to the bus. The first target device has a first address range containing a plurality of bits, and the second target device has a second address range containing a fewer number of bits than the first address range.

Abstract: A system and method for completing a read transaction between an initiator device and a host memory device in a computer system, in which the present invention optimizes the retry behavior of the initiator device and a target device. The system of the present invention includes a bus bridge device, wherein the bus bridge device includes a target device coupled to the initiator device via a bus; the host memory device coupled to the bus bridge device; and a timer mechanism coupled to the target device. The initiator device is adapted to initiate a present read transaction via the target device, such that an access is asserted between the initiator device and the target device. The timer mechanism is adapted to measure target latency for one or more read transactions preceding the present read transaction, and the timer mechanism is further adapted to use the target latency to calculate a dynamic target latency period.

Abstract: A system and method for using single address cycles and eliminating dual address cycles to transmit a target address in a computer system. The computer system comprises a bus, a central processing unit coupled to the bus, an initiator device coupled to the bus, and a target device coupled to the bus. The target device comprises a first configuration register which is adapted to use a configuration bit to indicate an address range of the target device. The central processing unit interrogates the first configuration register and communicates the address range indicated by the configuration bit to the initiator device. The initiator device comprises a second configuration register which is adapted to use a configuration bit to register the address range of the target device.

Abstract: A target configuration prediction system that provides an initiator coupled to a bus system with a prediction of the configuration type of a target. The present invention stores information regarding the address and configuration of targets and utilizes this information to predict the address of a target an initiator is currently attempting to access. The prediction is based upon the proximity of stored target addresses to a target address an initiator is currently trying to access and the probability that targets with addresses within certain ranges are the same target configuration type. The configuration type is determined by initiator component logic during an initial attempt at accessing a target and a status bit indicating the configuration type is stored in a status bit component.

Abstract: A system and method for preventing address aliasing when using a single address cycle to transmit a target address in a computer system that includes target devices having addresses of different ranges. The computer system comprises a bus, an initiator device coupled to the bus, a first target device coupled to the bus, and a second target device coupled to the bus. The first target device has a first address range comprising a plurality of bits, and the second target device has a second address range comprising a fewer number of bits than the first address range. The initiator device transmits a signal indicating the size of the target address and also separately transmits in a single address cycle the target address. The second target device disables its address decode logic in response to the signal from the initiator device provided that the size of the target address is greater than the second address range.

Abstract: A computer system in which a host bus is relieved from the burdens of data transfers between main memory and devices connected to an input/output (I/O) bus. Instead, the invention operates to place most of the burden of the data transfer on an internal bus within a bus arbitration unit so that the host bus is freed up much sooner than conventionally achieved. As a result, the computer system has substantially better performance because the host bus is available for other processing operations instead of being tied up with data transfers with devices (e.g., peripheral devices) connected to the I/O bus.

Abstract: A computer system in which a host bus is relieved from the burdens of data transfers between main memory and devices connected to an input/output (I/O) bus (e.g., peripheral devices). Instead, the invention operates to place most of the burden of the data transfer on an internal bus within a bus arbitration unit so that the host bus is freed up much sooner than conventionally achieved. Further, to reduce stalling of a processor seeking access to the main memory via the host bus and the internal bus, the host bus is able to gain access to the main memory using the internal bus during times in which the internal bus is temporarily not needed by the data transfer between the main memory and the peripheral devices.