The way we’ve always configured the ACE and Mini-ACE™ is for the 16-bit Buffered Mode. Is it correct to say that they use DMA?
A. Sort of. The memory configuration of the ACE/Mini-ACE™’s buffered mode is referred to as “shared RAM”, rather than DMA. However, in operation, the shared RAM interface uses a DMA-type mechanism in that there are data transfers between the Mini-ACE™’s protocol logic (encoder/decoder and memory management logic) and the internal shared RAM, that take placenotunder CPU control. That is, these transfers take place autonomously, independent of the host CPU. Since the host processor may also access this internal shared RAM, the Mini-ACE™ includes internal arbitration logic. This logic acts as a “traffic cop”, to enable – at any point in time, for either the host processor or the Mini-ACE™’s internal logic –but not both simultaneously– to be able access the shared RAM.
