摘要:
An apparatus for an method of sending and receiving data on a Universal Serial Bus using a memory shared among a number of endpoints are disclosed. The memory is a double buffer which allows the next packet to be prepared while the current packet is being transmitted. The invention also supports transmission retry.
摘要:
An apparatus for an method of sending and receiving data on a Universal Serial Bus using a memory shared among a number of end points are disclosed. The memory is a double buffer which allows the next packet to be prepared while the current packet is being transmitted. The invention also supports transmission retry.
摘要:
A method and apparatus for performing a control transfer on a Universal Serial Bus (USB) device. A USB device includes a memory space for reading and writing data transmitted over a USB network. The memory space is shared between a plurality of endpoints. A host initiates a control transfer by transmitting a SETUP token to a first endpoint. The endpoint must accept the SETUP token. If the first endpoint does not expect the SETUP token, or if another endpoint is active, the device stores the token until a buffer is allocated and the first endpoint is made active.
摘要:
An apparatus for and method of controlling a versatile USB endpoint pipe are disclosed. The USB endpoint pipe can be in various states which are determined by control commands. The control commands also determine the endpoint pipe type.
摘要:
An interprocess memory controller is described that may be used to provide multiple processes within a multi-process device with access to a shared physical memory. The described interprocess memory controller may enforce access rights to shared memory that has been allocated to the respective processes, thereby guarding the multi-process device from instability due to the unauthorized overwriting and/or unauthorized freeing of allocated memory. The described interprocess memory controller approach may streamline interprocess communication by allowing data associated with an interprocess communication to be passed from a first process to a second process by passing a pointer as well as access rights to a buffer in shared memory that contains the message data. In this manner, the described interprocess memory controller approach may avoid the inefficiency of interprocess communication approaches that copy message data from a shared memory controlled by a first process to a shared memory controlled by a second process.
摘要:
A system and method for reconstructing a service clock between two, first and second subsystems communicating therebetween, comprising a first subsystem operative to generate first subsystem timestamps, a second subsystem operative to generate second subsystem timestamps at a second frequency different from the first timestamps, wherein the generations of both first and second timestamps are based on sampling of the service clock by a common clock available at both subsystems, and an aligner for arithmetically aligning the different first and second subsystem timestamps to reconstruct the service clock.
摘要:
A Universal Serial Bus hub circuit includes an upstream port and a plurality of downstream ports. The hub circuit further includes input circuitry via which data received on one of the downstream ports is to be repeated to the upstream port. Asynchronous event detection circuitry is to detect an asynchronous event in the received data for the one downstream port. Port selection circuitry to select the one downstream port. Timer circuitry is to measure a time period from a time that the asynchronous event detection circuitry detects an asynchronous event. Synchronous event detection circuitry is to detect a synchronous event in the received data for the one port. End-of-event generation circuitry generates a simulated end-of-event signal if the detected synchronous event is not before the end of the measured time period, and provides the simulated end-of-event signal to the upstream port.
摘要:
An apparatus for and method of transmitting and synchronizing isochronous data on a USB endpoint pipe are disclosed. Also disclosed are a double buffering capability, a transmission delay capability, a synchronization capability, and a clock adjustment capability.
摘要:
A method and apparatus for providing a programming interface to a Universal Serial Bus Device. The programming interface is partitioned so that an external controller does not handle intermediate transfers such as packet retry, handshake packets or intermediate response to error conditions. The programming model consists of a number of endpoint pipes, each of which can be configured to provide one of several functions.
摘要:
A method and apparatus for dynamically configuring a USB device. The USB device includes a plurality of mappings for relating a received token to an endpoint pipe. The mappings are configured at initialization, and are dynamically selected during operation of a USB network.