A method of configuring a System on Chip to execute a CNN process comprising CNN layers, the method comprising, for each schedule: determining memory access amount information describing how many memory accesses are required; expressing the memory access amount information as relationships describing reusability of data; combining the relationships with a cost of writing and reading from external memory, to form memory access information; determining a memory allocation for on-chip memory of the SoC for the input FMs and the output FMs; and determining, dependent upon the memory access information and the memory allocation for each schedule; a schedule which minimises the memory access information of external memory access for the CNN layer of the CNN process; and a memory allocation associated with the determined schedule.