Renesas Electronics Corporation

Renesas Technology Corp.

Murata Manufacturing Co., Ltd.

Chiaki Fujii

Takanobu Naruse

Fumie Katsuki

Takashi Ichimura

In a wiring substrate, a double data rate (DDR) memory and a memory controller controlling the DDR memory are mounted. Further, in the wiring substrate, plural equal-length wires connecting the DDR memory and the memory controller are formed. The plural equal-length wires include a differential transmission line, such as a clock wire transmitting a clock signal, which is connected via a common mode choke coil. The differential transmission line may have a wire length shorter than a wire length of another equal-length wire, by a wire length corresponding to delay time of a transmission signal due to the common mode choke coil.

Wiring substrate in which equal-length wires are formed

The data processor enhances the bus throughput or data throughput of an external memory, when there are frequent continuous reads with a smaller data size than the data bus width of the external memory. The data processor includes a memory control unit being capable of controlling in response to a clock an external memory having plural banks that are individually independently controllable, plural buses connected to the memory control unit, and circuit modules capable of commanding memory accesses, which are provided in correspondence with each of the buses. The memory control unit contains bank caches each corresponding to the banks of the external memory. Thereby, the data processor enhances the bus throughput or data throughput of the external memory, since the data processor stores the data read out from the external memory temporarily in the bank caches and to use the stored data without invalidating them, when performing a continuous data read with a smaller data size than the data bus width of the external memory.

Data processor

Data processor having a memory controller with cache memory

Data processor having a memory control unit with cache memory

Growing community of inventors

Yokkaichi, Japan

Chiaki Fujii