computer-architecture-dma.html


* created: 2025-06-23T23:17
* modified: 2025-07-08T12:52

title

Direct Memory Access Controller

description

The DMA-Controller handles the transmission of data from one devices to another. The CPU is not involved during that process and can handle other tasks during that time. When the transfer finishes the CPU gets an interrupt.

Transferring Data

TODO!

Data transfer without a DMA

  1. The CPU sends the address of the desired data word to the hard drive controller.
  2. The hard drive controller retrieves the data word from the hard drive and makes it available in its data register.
  3. The hard drive controller sends an interrupt to the interrupt controller.
  4. The interrupt controller receives the interrupt and manages it.
  5. The interrupt controller informs the CPU about the interrupt from the hard drive controller.
  6. The CPU starts the corresponding interrupt service routine.
  7. The service routine copies the data word into a register on the CPU.
  8. The service routine sends the data word from the CPU to the main memory.
  9. The main memory stores the data word in the desired memory cell.
  10. The interrupt service routine informs the interrupt controller that the interrupt has now been fully handled.