What is DMA?



DMA is a technique that allows data to be transferred between devices without the intervention of the CPU. In a typical computer system, data is transferred from one device to another via the CPU. The CPU initiates the transfer, reads data from one device, and writes it to another device. This process can be time-consuming and takes up valuable CPU time, which can slow down the system. It eliminates the need for the CPU to be involved in data transfer by allowing data to be transferred directly between devices. These controllers can be built into the devices or added as a separate component to the system.

The DMA controller operates independently of the CPU and uses its own memory address and data buses to transfer data between devices. The DMA controller is programmed by the CPU to read data from one device and write it to another. The DMA controller can transfer data in blocks, making the process faster and more efficient.

When the CPU needs to transfer data, it initiates the transfer by sending a command to the DMA controller. The DMA controller then takes over the transfer process, freeing up the CPU to perform other tasks. The DMA controller reads data from the source device, writes it to its own memory buffer, and then writes the data to the destination device.

Benefits of DMA:

  1. Reduced CPU usage: DMA reduces the CPU usage by transferring data between devices without involving the CPU.
  2. Faster data transfer: DMA allows data to be transferred in blocks, which makes the process faster and more efficient.
  3. Increased system performance: By reducing the CPU usage and speeding up the data transfer process, DMA can significantly increase the overall performance of the system.
For more details, please refer the link shared below:

https://embeddedwala.com/Blogs/embeddedsystem/what-is-dma

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