The AMBA APB interface generates read and write decodes for accesses to data, and control and status registers.

The AMBA APB is a local secondary bus which provides a low-power extension to the higher bandwidth Advanced High-performance Bus (AHB) or Advanced System Bus (ASB), within the AMBA system hierarchy. The AMBA APB groups narrow-bus peripherals to avoid loading the system bus and provides an interface using memory-mapped registers that are accessed under programmed control.