Direct memory access controller

A method of operating system-on-chip (SoC), the system-on-chip comprising:

• a processor;
• a peripheral comprising a data interface and a data-attribute interface;
• a direct memory access (DMA) controller for the peripheral;
• a memory;
• a bus system connecting the processor, the DMA controller, and the memory;
• a data link between the DMA controller and the peripheral, for transferring data between the DMA controller and the peripheral, wherein the data can be any of a plurality of different types of data;
• and
• a data-attribute link between the DMA controller and the peripheral, separate from the data link, for transferring data-attribute information between the DMA controller and the peripheral wherein the data-attribute information is associated with data transferred over the data link and represents a type, from the plurality of different types, of the data transferred over the data link,
• wherein the processor, the peripheral, the DMA controller, the memory, the bus system, the data link and the data-attribute link are provided on the system-on-chip,
• wherein the peripheral is separate from the processor,
• wherein the DMA controller is separate from the processor, and
• wherein the method comprises:
• transferring data of a first type, from the plurality of different types, between the memory and the data interface of the peripheral over the data link;
• and
• transferring data-attribute information, associated with the data and representative of the first type, between the memory and the data-attribute interface of the peripheral over the data-attribute link.