| 摘要 |
A DMA controller achieving real-time control of a DMA transfer relating to periodically operated peripheral devices at a low cost and with low power consumption. A typical embodiment of the invention is a DMA controller having: a counter for counting time; a counter comparator comparing a value of the counter and a counter value indicating an expected time of a DMA transfer; a peripheral device read unit reading a register of the peripheral device to acquire a state of a peripheral device by; and a state comparator comparing a value of the register read by the peripheral device read unit and a start condition of the DMA transfer, in which, with being triggered by establishment of a comparison result by the counter comparator, in accordance with a specified order, a processing of updating the counter value indicating the expected time of a DMA transfer to a value indicating a next expected time, a read of the register of the peripheral device by the peripheral device read unit, a comparison by the state comparator, and a DMA transfer on the condition that the comparison result by the state comparator is established are executed. |
