Embedded Systems Design, 2nd Edition

166 Embedded systems design

• Issue the address

Assuming the controller has the bus, it will then issue the

bus to activate the target memory location. A variety of

interfaces are used — usually dependent on the number of

pins that are available and include both non-multiplexed

and multiplexed buses. In addition, the controller provides

other signals such as read/write and strobe signals that can

be used to work with the bus. DMA controllers tend to be

designed for a specific processor family bus but most recent

devices are also generic enough to be used with nearly any

bus.

• Transfer the data

The data is transferred either from a holding buffer within ...