Pipeline structure is considered to be the best solution to overcome LSI design limitation constraints by allowing divide and conquer design principle. In addition, it also helps us diminish wiring lengths across and thus minimizing extrinsic degradations. However, with increase in clocking rate, the structure also suffers from excessive power consumption and skew problems associated with synchronous clock distribution. A self-timed pipeline structure is proposed to solve these problems simultaneously [1]. A folded pipeline scheme employed in a folded queue (FQ) demonstrates another functional advantage of the selftimed pipeline (STP) scheme. An FQ capable of differentiating 100M packets/s streams on Diffserv basis [2] is successfully fabricated in 0.18µm CMOS process. Figure 8.1.1 shows the basic structure of an STP scheme where data transfer between the stages of a pipeline is controlled by a chain of self-timing transfer control units. Every control unit generates a clock signal to the data latches when send and ack signals are both active. That is, the send signal indicates that the processed data in the preceding stage is ready to be fed to the inputs of the latches and the ack signal shows that the succeeding stage is empty. A piece of input data traverses pipeline stages until the data arrives at an occupied stage, i.e., one in which active data are present. If a piece of data at the end of a pipeline is removed, the remaining data in each of the pipeline stages step successively to succeeding stages in a bucket relay fashion. Therefore, the asynchronous FIFO exhibits an elastic nature by adjusting the effective length of the pipeline to the amount of data stream residing in the pipeline. The STP scheme provides good design and signal integrity by virtue of localized control and wiring, even in deep submicron chips. These features are utilized in the development of self-timed super-pipelined data-driven chip-multiprocessors (DDMPs) [1].The mutual interactions among two or more STPs potentially provide various functionalities for developing SoCs. The FQ module shown in Fig. 8.1.2 is proposed as one of these extensions of STP to achieve the queueing and scheduling speed required for network processors working at over 10Gb/s. This figure shows a folded pipelined queue FQ constructed by folding a linear STP in half and attaching a shortcut path at each stage of the pipeline. The bypass stage allows a piece of data flowing at the up-stream pipeline to bypass the pipeline when a corresponding stage of the opposite down-stream pipeline is not occupied, thanks to the elastic mode of operation. In other word, the data are automatically queued in the FQ if its egress is congested under certain external conditions. Therefore, the FQ behaves flexibly along with the egress traffic condition as if it were a variable length FIFO queue.Data branching and merging transfer in each stage of the FQ are locally controlled by the TC circuits, as shown in Fig. 8.1.3. The data branching off to the shortcut pass is controlled by a...
The design and implementation of home appliance control based on information from sensors is presented. In a ubiquitous networking society, there are a lot of devices connected to a network. However, many kinds of networks coexist, and they use different communication protocols. Therefore, a technology to integrate different networks is necessary to provide flexible services, which can control various devices connected to different networks where different protocols are used. At the same time, the technology of sensor networks is important in such a society. Sensors also use different protocols. Therefore, using sensing data from different kinds of sensor networks is difficult. To collect and process information from various kinds of sensors, we designed and implemented a Sensor Gateway. To control home appliances, protocols defined by the Peer-to-Peer Universal Computing Consortium are used in our system.
This demonstration presents the system shown in the paper accepted at CCNC 2009 [1]. By using this system, control of a network camera programmed to be activated by a sensor is possible. With mobile devices, a user can set or delete the service, which would be executed when a predefined event occurred. When a situation satisfies the predefined criteria of the program utilizing the sensor, this architecture detects it, and executes the service which is determined in advance. Precise definition of the event, which is composed of several types of sensors, is also possible. This architecture is not limited by vendor but can be adapted to many kinds of hardware. Therefore, a user can use sensors without being conscious of the difference of vendors. We demonstrate how to define an event and set the service for the defined event.
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