What is DMA and how does it improve system performance?

DMA (Direct Memory Access) transfers data between memory and peripherals without CPU intervention. The DMA controller handles transfers while CPU executes code. Process: CPU configures DMA (source, destination, count), DMA performs transfer using bus during CPU idle cycles or bus arbitration, DMA signals completion via interrupt. Benefits: Reduces CPU overhead, enables higher throughput, and improves power efficiency. Use cases: ADC buffer filling, UART data transfer, SPI/I2C bulk transfers, and memory-to-memory copying. Modern MCUs have multiple DMA channels with priority and chaining.