Kabushiki Kaisha Toshiba

Takeshi Takamiya

Yoshimasa Aoyama

Yasunori Maki

According to one embodiment, a memory controller comprises a counter and a setting module. The counter is configured to count the number of valid pages in a block includes a page to be invalidated, when data is written in a nonvolatile memory. The setting module is configured to set the block as an object of compaction when the number of valid pages counted by the counter is smaller than a predetermined number.

Memory controller and memory control method

An SD memory card host controller supplies a clock to an SD memory card and issues a read command. After that, the host controller stops supplying the clock to the SD memory card during latency of read data from receipt of a response to the read command from the SD memory card to readout of data. The host controller resumes supplying the clock immediately before a data cycle starts. Power savings can thus be achieved by controlling the clock to be supplied to the SD memory card.

Method and apparatus of clock control associated with read latency for a card device

In a computer system where a plurality of bus masters are connected to a bus, a bus arbiter connected to the bus, comprises an arbitration circuit that arbitrates between the bus access request signals from the plurality of bus masters and outputs a bus access grant signal to a single bus master of the plurality of bus masters, unit for holding a value indicating the duration during which the switching of the bus access grant signal is to be inhibited, counting unit capable of counting on the basis of the value held in the holding unit, unit for causing the counting unit to start counting at the time when the arbitration circuit has given a bus access grant signal to a bus master, unit for inhibiting the arbitration circuit from switching the bus access grant signal in the period until the counting has been completed, as long as the bus access request signal from the bus master to which the bus access grant signal has been given remains active, and unit for permitting the arbitration circuit to switch the access grant signal after the counting has been completed.

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Iruma, Japan

Takeshi Takamiya