DMA TRANSFER DEVICE, DATA TRANSFER CONTROL METHOD, AND DATA TRANSFER CONTROL PROGRAM

摘要

PROBLEM TO BE SOLVED: To efficiently control data transfer using a DMA controller and to simply describe a control program of CPU which controls the entire data transfer. SOLUTION: The DMA controller (DMAC) 200 sequentially reads transfer set values (descriptors) of data transfer into a register (REG) 201 and performs a DMA transfer process based on the read transfer set values. The DMAC 200 is constituted so as to accept NOP specification which specifies non-execution of DMA transfer as the transfer set values. When the NOP specification is set with the transfer set values read into the REG 201, the controller generates an NOP interrupt signal and ends the transfer process without performing the DMA transfer. The CPU side can set in advance the transfer set values including the NOP specification when too short transfer length is determined and can perform the transfer process on the CPU side according to the NOP interrupt signal. COPYRIGHT: (C)2008,JPO&INPIT