Patent ID: 7174395

Claim:
A method comprising: storing a packet of unit data, obtained from an external bus by asynchronous communication, into a first memory; transferring the packet stored in said first memory to a second memory via an internal bus by a Direct Memory Access (DMA) transfer; setting top infonnation indicating that a first unit data which is DMA-transferred from said first memory to said second memory is a top of the packet, and end information indicating that a last unit data which is DMA-transferred from said first memory to said second memory is an end of the packet into a control register; transferring data obtained by decomposing the packet stored in said second memory to an internal sianal processing system; packetizing the data from said internal signal processing system; storing the packetized data into said second memory; transferring the packetized data stored in said second memory to a third memory via said internal bus by the DMA transfer; and sending asynchronously the data from said third memory to said external bus, wherein said DMA transfer is executed in accordance with the settings in said control register, and a setting, in which the top information indicates the top of the packet and the end information indicates the end of the packet, is reflected to a transfer destination of the DMA transfer.