There are multiple levels of memory in the AI Engine-ML architecture:
Memory Module attached to the AI Engine-ML (64kB). Access from the processor or using internal DMA with dedicated address generators (2xMM2S, 2xS2MM).
memory tile (512 kB): 1 or 2 per column. Access with internal DMAs with dedicated address generator (6xS2MM, 6xMM2S).
External memory: DDR or HBM which is also addressed by DMAs located in the PL-AIE array interface.
Data in these memories can be seen as a single dimension set of data, but depending on the memory the maximum dimensionality can be 3 (AIE Tile DMA, Interface Tile DMA) or 4 (memory tile DMA). Currently (2022.2) DMA BDs of the memory tile and the Interface Tile can be programmed from within the graph.
This programming process is done through what we call Tiling Parameters. These parameters describe how the data should be accessed in the memory on a tile basis. Dimension 0 is the dimesion where the data are contiguous in memory. The overall dimension of the buffer is specified and then the tile dimension and the number of tiles to read in each dimension.