Fujitsu Corporation

Masato Maebayashi

Makoto Kimura

Masahiro Tamagawa

A data processing apparatus includes a first circuit unit operating with first clocks of a predetermined cycle, a second circuit unit operating with second clocks of a predetermined cycle different from the first clock cycle, and a first circuit block which generates and outputs a train of pulses in accordance with the first clock cycle. The second circuit unit includes a second circuit block which receives the train of pulses output from the first circuit block, and samples the train of pulses using the second clock as a sampling signal, to thereby output the sampled train of pulses; a third circuit block which receives the train of pulses output from the second circuit block, and delays the train of pulses by a predetermined number of clocks in response to the second clock, to thereby output the delayed train of pulses; and a fourth circuit block which receives the train of pulses output from the second circuit block and the train of pulses output from the third circuit block, and effects a predetermined processing with respect to both trains of pulses, to thereby generate and output a train of pulses with a cycle approximately equal to the first clock cycle. efficiently realizes data transfer processings between circuit units operating with different clock cycles.

Data processing apparatus adapted for data transfer between circuit units operating with different clock cycles

A method of controlling data transfer through a system bus between units in a computer system employs a split transfer technique that transfers data transfer requests separately from responses to the requests. The method provides one of the units with a bus grant signal to allow the unit to transfer a plurality of transferrable statuses to another unit that has requested them.

Method of an apparatus for controlling data transfer

A firmware modification system in a data processing apparatus, containing a processor for executing a program and a working program holding unit for holding therein data of the program executed by the processor. The system also includes fixed program data storing unit for storing a fixed program data and a modification data storing unit for storing modification data with which the fixed program data is to be modified, where the modification data storing unit is accessible from outside of the data processing apparatus for writing the modification data therein. A fixed program data loading unit is used for reading from the fixed program data storing unit, and loading the fixed program data in the working program holding unit to hold the fixed program data therein, and a working program modifying unit is used for modifying data of the program which is held in the working program holding unit, with the modification data stored in the modification data storing unit.

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Kawasaki, Japan

Masato Maebayashi