13. A generic DMA controller consists of the following components:

• Address generator

• Address bus interface

• Data bus interface

• Bus requestor

• Interrupt signal circuits

• Local peripheral controller The local peripheral controller is the circuitry that the DMA uses to select among the peripherals connected to it. This circuit is activated right after the bus is requested. What is the purpose of each of the other components listed above, and when are they active? (Use Figure 7.6 as a guide.)