What is DMA and when should it be used?

DMA (Direct Memory Access) allows peripherals to transfer data directly to/from memory without CPU involvement. How it works: CPU configures DMA controller (source, destination, size, trigger). DMA handles the transfer while CPU does other work. Interrupt notifies CPU when transfer completes. Benefits: Reduces CPU overhead for data movement. Enables higher throughput (parallel operation). Essential for high-speed data streams. Use cases: ADC continuous sampling to buffer. SPI/I2C large data transfers. Memory-to-memory copies. Audio streaming, display refresh. Considerations: Memory alignment requirements. Cache coherency (on cached systems). Priority and arbitration with CPU. Scatter-gather for non-contiguous transfers. Circular buffer mode for streaming applications.