摘要:
An apparatus and method for controlling data read access to memory, in response to an access request sent through a system bus. The apparatus includes an data storage device for preserving data corresponding to a predetermined address; a judging device for judging whether an access address indicated by the access request matches the predetermined address; and a control device for making the data storage device output data preserved therein to the system bus when the access address has been judged to match the predetermined address, and for making the data storage device hold data corresponding to a next address subsequent to the access address when the access address has been judged not to match the predetermined address.
摘要:
A transfer-target unit outputs commands for data reading and data writing. An address generator generates control signals in accordance with the commands, and outputs the number of bytes of data first transferred by read access. A command generator generates control commands in accordance with the control signals to control an SDRAM. At this time the command generator judges the number of transferred bytes to control so that the SDRAM executes instructions in order from an instruction which is the most efficient in data transfer. That is, in the case where data is read across a bank boundary, the command generator judges which is to be executed first between read processing in a bank 0 and active processing in a bank1, to control the SDRAM. A data processor mediates data transfer between the transfer-target unit and the SDRAM in accordance with the control commands. In this way, it is possible to issue commands so as to terminate data transfer in the minimum number of cycles in the case where data read processing is continuously performed to different banks. The number of cycles required for two continuous access (access to the bank 0 and the bank 1) can be thus reduced, thereby increasing effective transfer rates of the SDRAM.
摘要:
A data transfer system comprises a plurality of terminals; a plurality of high-speed data transfer units connected to the terminals through a network, each data transfer unit comprising a plurality of storage devices and a storage device group control device or unit for controlling readout of data from the storage devices, and dividing and storing data requested by the terminals; a virtual storage device group controlling device or unit for controlling readout of data from virtual storage device groups, each virtual storage device group being constructed by selecting a storage device from each high-speed data transfer unit; and an instruction conversion unit or device for receiving a data readout instruction on the basis of data requests output from the terminals, which instruction is given to the virtual storage device groups, from the virtual storage device group control unit or device, and converting the instruction into a data readout instruction to the storage devices from the storage device group control unit or device. In this data transfer system, the load for the data transfer processing is equally distributed among the high-speed data transfer units even when data transfer requests are output from plural terminals.
摘要:
A field effect transistor of the present invention has in a base layer (33) a difference in levels constituted by an upper main surface (35a) a wall surface (35b) and a lower main surface (35c), the wall surface (35b) having a gate insulating film (39) and a gate electrode (41) in a sequential order at least in a direction extending from the upper main surface (35a) to the lower main surface (35c), the wall surface (35b) being provided, on both sides of the portions thereof corresponding to the gate insulating film (39) and gate electrode (41), with inpurity diffusion regions for forming of source and drain, respectively.Accordingly, the gate electrode (41) is provided in a manner that the gate width which needs to have a relatively large size is set in a direction vertical to the upper main surface of the base layer. This makes it possible to improve the degree of integration effectively.
摘要:
A signal receiving device and signal receiving method to pass a desired frequency component of an intermediate frequency signal by using an IF filter without increasing a chip area. The signal receiving device comprises: a mixer to mix a received frequency signal with a local oscillation frequency signal to generate an intermediate frequency signal; an IF filter to pass a predetermined frequency component of the intermediate frequency signal; a controlling part which adjusts, according to a frequency band of the intermediate frequency signal, the frequency band of the IF filter, and adjust, according to a center frequency set in the IF filter that fluctuates with the adjustment, a center frequency of the intermediate frequency signal to be inputted in the IF filter; and a demodulating part to demodulate a frequency component of the intermediate frequency signal outputted after passing through the IF filter.
摘要:
A control voltage Vin that has been input is sequentially reduced at NMOS's 111˜113 constituting means for voltage reduction. The individual voltages resulting from the voltage reduction are applied to control electrodes of MOS varactors 211˜213 constituting voltage-controlled variable-capacitance elements which are connected in parallel and, thus, the capacitance values of the individual MOS varactors 211˜213 are determined. An LC resonance circuit constituted of the MOS varactors 211˜213 and a coil 22 resonates at a specific frequency, NMOS's 23 and 24 constituting means for switching engage in on/off operation and oscillation occurs at an oscillation frequency corresponding to the voltage Vin resulting in an oscillation signal output through output terminals 3 and 4. Thus, an LC resonance circuit that allows the rate at which the capacitance values of the voltage-controlled variable-capacitance elements change to be set freely in correspondence to the particulars of design and a high-performance voltage-controlled oscillation circuit (VCO) that employs this LC resonance circuit and enables good control are provided.
摘要:
A bus bridge apparatus that connects two system buses independent of each other to which a bus arbiter operating independently and located outside of the apparatus, has a function for serving as a master and a slave of the system buses, a base address holding means, and a bus address generating means. When, to access a slave device on a first system bus, a master device on a second system bus attempts to access the apparatus, generating offset from addresses received from the master device and combining the offset with base addresses previously stored in said base address holding means, to generate an access destination address in the slave device by using said bus address generating means, this bus bridge apparatus performs functions: (i) issuing the generated access destination address by serving as a bus master on the first system bus, to access the slave device; and (ii) performing data transfer between the master device and the slave device by serving as a slave of the master device on the second system bus. It is thus possible to realize mutual access between system buses having an independent arbitration function, without changing system design.