Abstract: A method of and apparatus for communicating data using a hub. The method includes determining a first estimated unused capacity left in a first frame in which a second transaction is to be performed between a hub and an agent. The method then includes determining an amount of a first data that can fit into the estimated unused capacity and that is to be sent to the hub during a first transaction and then sent by the hub to the agent during the second transaction. The method also includes sending the first data to the hub during the first transaction.

Abstract: A method and apparatus for allowing memory, cache and/or a processor to remain powered down while repetitive transactions are carried out on an I/O bus and actions are taken in response to feedback received from I/O devices coupled to the I/O bus.

Abstract: A timing enhancement for a USB controller determines if a short data packet is present. If so, data is placed in a buffer. If the buffer is full, data is sent. If the buffer is not full, the system looks to see if more data is available, if so takes it, if not it sends whatever is available.

Abstract: A method of and apparatus for communicating data using a hub. The method includes determining a first estimated unused capacity left in a first frame in which a second transaction is to be performed between a hub and an agent. The method then includes determining an amount of a first data that can fit into the estimated unused capacity and that is to be sent to the hub during a first transaction and then sent by the hub to the agent during the second transaction. The method also includes sending the first data to the hub during the first transaction.

Abstract: A system and method for serial bus budget development and maintenance. The present invention relates to a method for budgeting transactions under a Universal Serial Bus (USB) protocol, utilizing split transactions, such as USB 2.0. The present invention provides for budgeting transactions occurring across a high-speed to full/low-speed translation, accommodating the full/low speed transactions as well as high-speed splits and data overhead in accordance with USB protocol.

Abstract: A bus controller and its associated device drivers are provided to a digital system to operate and control a peripheral bus, including the selective operation of at least a first portion of the peripheral bus in a store-and-forward manner. The device drivers include a number of programming instructions. Upon programmed with the programming instructions, a digital system is enabled to operate the bus controller to facilitate communication with a first bus agent in this first portion. The programming instructions package a number of request packets destined for the first bus agent into a multi-packet package, schedule the multi-packet package to be transmitted in bulk, at a first communication speed, to a first hub in the first portion, for the first hub to buffer the request packets, and then forward the request packets to the first bus agent, on a packet-by-packet basis and at a second communication speed. In one embodiment, the second communication speed is slower than the first communication speed.

Abstract: A host controller, such as a host controller for a Universal Serial Bus, may process isochronous and interrupt transfers on a preferential basis. If time permits, bulk and control transfers may be executed. The bulk and control transfers may be executed in queues having a queue context made up of a queue head and one or more transfer descriptors. These queues may be processed one after another in a circular linked list. By uniquely marking an element in the circular linked list and determining the status of the transfer operation, the host controller can be avoid thrashing the bus when the reclaim list is empty.

Abstract: A method and apparatus for allowing memory, cache and/or a processor to remain powered down while repetitive transactions are carried out on an I/O bus and actions are taken in response to feedback received from I/O devices coupled to the I/O bus.

Abstract: A digital system is provided with a bus controller to operate and control a peripheral bus, wherein the bus controller selectively operates at least a first portion of the peripheral bus in a store-and-forward manner. The bus controller facilitates communication with a first bus agent in this first portion by sending a number of request packets destined for the first bus agent to a first hub in the first portion, in an integrated multi-packet form, in bulk, and at a first communication speed. The first hub buffers the request packets, and then forwards the request packets to the first bus agent, on a packet-by-packet basis, and at a second communication speed. In one embodiment, the second communication speed is slower than the first communication speed.

Abstract: System and method for supporting split transactions on a bus. The method may comprise processing a periodic frame list of external bus data frame by frame, and traversing each frame node by node. When a save place node is encountered in a first frame, the traversing jumps to a destination node pointed to by the save place node in a second frame, and continues the traversing there. When a restore place node is encountered when traversing the nodes in the second frame, the traversing returns to the node after the save place node in the first frame and continues the processing in the first frame. The method may be implemented on a system that comprises a processor, a memory, an internal bus, and an external bus controller. The external bus controller and the external bus data may support one or more versions of the Universal Serial Bus standard.

Abstract: A method and apparatus for generating, initializing, and scheduling of two interrupt queue heads to represent a single endpoint are described. In an embodiment, a method includes generating primary and secondary interrupt queue heads to represent a single interrupt endpoint. The method further includes initializing the primary and secondary interrupt queue heads. The method also includes scheduling the primary and secondary queue heads in immediately subsequent frames.

Abstract: A method and apparatus for deterministic removal and reclamation of work items from an expansion bus schedule are disclosed herein. A work item is removed from an enabled expansion bus schedule data structure and a coherency signal is then generated utilizing an expansion bus host controller. The work item is then reclaimed in response to the generation of the coherency signal. In one embodiment, the enabled expansion bus schedule data structure is a Universal Serial Bus (USB) asynchronous schedule including a plurality of queue heads.

Abstract: A system and method for serial bus budget development and maintenance. The present invention relates to a method for budgeting transactions under a Universal Serial Bus (USB) protocol, utilizing split transactions, such as USB 2.0. The present invention provides for budgeting transactions occurring across a high-speed to full/low-speed translation, accommodating the full/low speed transactions as well as high-speed splits and data overhead in accordance with USB protocol.

Abstract: A method and apparatus for traversing a schedule with a bus master, the schedule having a plurality of elements, each element having information pertaining to one of a plurality of endpoints; executing transactions on a bus in accordance with the information pertaining to the plurality of endpoints; counting flow control events issued by individual endpoints; and skipping elements in the traversal of the schedule, the elements being skipped corresponding to endpoints which have issued a threshold number of flow control events.

Abstract: An I/O peripheral device is equipped with a first collection of circuitry to enable the I/O peripheral device to provide a store-and-forward manner of operation to a segment of a peripheral bus. The first collection of circuitry includes first buffering circuitry to buffer request packets destined for a first bus agent, received from a bus controller in an integrated multi-packet form, in bulk, and at a first communication speed. Furthermore, the first collection includes control circuitry to forward the request packets separately, in a packet-by-packet basis, to the first bus agent, in a second communication speed. In one embodiment, the second communication speed is slower than the first communication speed. The I/O peripheral device further includes second buffer circuitry to buffer response packets to a request from the first bus agent provided separately, and each at the slower second communication speed.

Abstract: A property maintenance scheduling system has a calendar for displaying a current month. The calendar has an area for listing property maintenance to be performed during the month. The maintenance system further has two pluralities of labels. The first labels are to be placed on the calendar to indicate the date that specific maintenance is due to be performed. The second labels are to be placed on each item to record the date on which an item will next be serviced. The calendar may also be electronic in nature. A notebook may further be provided in the property maintenance scheduling system. The notebook is used for detailing the procedure for each property maintenance task to be performed during the month. The notebook may further be used for recording details of the work performed for each property maintenance task.

Abstract: A method and apparatus for ensuring frame integrity in a bus system are disclosed. In the disclosed system, each scheduled transaction is evaluated before execution to determine whether there is enough time in the frame to complete the transaction. By separately evaluating each transaction at the time of execution, held off transactions are not aborted if the frame ends before the transaction completes. Each transaction is evaluated by determining the approximate length of the transaction and comparing the approximate length to the number of byte times remaining in the frame. A step function is used to determine the approximate length by adding one of two possible constant values which take into account transaction overhead to the number of data bytes in the transaction, the selected constant value being dependent upon the number of data bytes, a smaller constant value being added for smaller transactions and a larger transaction value being added for larger transactions.