Renesas Electronics Corporation

Nec Electronics Corporation

Toru Ikeuchi

Yukihiko Akaike

A data processing apparatus includes a memory which receives and outputs data with a predetermined data width, an operation circuit which outputs a read command or a write command to access the memory, and an access control circuit which replaces a part of first read data read from the memory with a partial data, and outputs partially replaced data as write data to the memory when receiving the write command and the partial data with a data width smaller than the predetermined data width associated with the write command, from the operation circuit. The access control circuit replaces a part of second read data which has been acquired in response to the read command outputted before, instead of the first read data, with the partial data, and outputs replaced partially data as the write data if the write command has been outputted in connection with a read command outputted before the write command.

Data processing apparatus, memory controller, and access control method of memory controller

DMAC includes current transfer setting registers and next transfer setting registers. Each of the current transfer setting registers stores transfer source address, transfer destination address and transfer count. The next transfer setting registers stores a transfer setting of a DMA transfer carried out after completing a DMA transfer according to a current transfer setting stored in the current transfer setting registers as a next transfer setting. Further, flags are provided for controlling to write to each of the next transfer setting registers.

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Kanagawa, Japan

Toru Ikeuchi