A processor includes a central processing unit (CPU) and a direct memory access (DMA) adapter circuit. The DMA adapter circuit includes a DMA controller circuit and is configured to interface with a legacy internal hardware peripheral and with a DMA-enabled internal hardware peripheral. The DMA-enabled internal hardware peripheral includes a first special function register (SFR). The legacy internal hardware peripheral includes no DMA features. The CPU is configured to execute a legacy application that accesses a setting in memory through the legacy internal hardware peripheral. Execution of the legacy application includes access by the CPU of the setting in memory. The DMA controller circuit is configured to access the setting in memory during execution of a DMA-enabled application through the DMA-enabled internal hardware peripheral.