5.1软硬件通信的基本方式 直接存储器存取(DMA)方式 A typical DMA operation S6:Once the DMA operations have been completed, the device releases the bus by asserting the bus release signal. S7:Processor acknowledges the bus release and resumes its bus cycles from the point it left off.A typical DMA operation S6: Once the DMA operations have been completed, the device releases the bus by asserting the bus release signal. S7: Processor acknowledges the bus release and resumes its bus cycles from the point it left off. 直接存储器存取（DMA）方式 5.1 软硬件通信的基本方式