DMA CONTROLLER, IMAGE FORMING DEVICE, DMA TRANSFER CONTROL METHOD, COMPUTER PROGRAM, AND RECORDING MEDIUM

摘要

PROBLEM TO BE SOLVED: To know the number of blocks for which parameters are held in a DMA parameter-setting FIFO, at any time.;SOLUTION: After setting parameters to the FIFO (S101), a DMA transfer start instruction is sent to a DMA controller from a CPU (S102). When the DMA controller receives the DMA transfer start instruction, the DMA controller starts DMA transfer of data to an I/O device (S103), and confirms the number of the parameters remaining in the FIFO by register read (S104). When the data to be DMA-transferred are present (S105), the DMA controller newly sets parameters to the FIFO such that capacity of the parameters does not exceed total capacity of the FIFO (S106), and DMA-transfers a plurality of blocks. When the data to be DMA-transferred are absent (S105), the DMA controller DMA-transfers the data of the residual blocks (S107), generates a completion interrupt (S108), and completes a DMA transfer process.;COPYRIGHT: (C)2005,JPO&NCIPI