Question

Which of the following is used to request the bus from the main CPU?

(a) data bus

(b) address bus

(c) bus requester

(d) interrupt signal

The question was asked in an interview.

Question is from DMA topic in section Basic Peripherals of Embedded Systems

Answer 1

Right answer is (c) bus requester

The explanation is: The bus requester requests the bus from the main CPU. In earlier design, the processor bus does not support the multi master system and there were no bus request signals. In such cases, the processor clock was extended.