Quiz on DMA Controllers

What does DMA stand for in a DMA controller?

• Direct Memory Access

• Direct Memory Allocation

• Dynamic Memory Access

• Dynamic Memory Allocation

What is the primary purpose of a DMA controller?

• To manage input/output operations

• To perform arithmetic operations

• To control memory access without CPU intervention

• To handle interrupts

Which of the following is a key advantage of using DMA?

• Increased CPU load

• Reduced system performance

• Faster data transfer

• More complex programming

In a typical DMA controller, how many channels are available for different DMA transfers?

• One

• Two

• Four

• Eight

Which signal is used by the DMA controller to gain control of the system bus?

• Address signal

• Data signal

• DMA request signal (DREQ)

• DMA acknowledge signal (DACK)

What type of transfer mode allows the DMA controller to transfer data continuously without CPU intervention?

• Burst mode

• Cycle stealing mode

• Block mode

• Handshake mode

What happens in cycle stealing mode of DMA operation?

• The DMA controller transfers data in large blocks

• The DMA controller transfers data one byte at a time, stealing cycles from the CPU

• The CPU transfers data without DMA intervention

• The DMA controller waits for an interrupt before transferring data

Which signal does the DMA controller use to indicate that a data transfer has been completed?

• DMA request signal (DREQ)

• DMA acknowledge signal (DACK)

• Interrupt request signal (IRQ)

• Memory read signal (MRD)

What is the role of the DMA address register in a DMA controller?

• To store the address of the data to be transferred

• To store the data to be transferred

• To store the DMA channel number

• To store the status of the DMA operation

Which of the following is a common DMA controller used in microprocessors?

• 8255

• 8086

• 8257

• 80386