Memory blocks are allocated for a microcontroller having one memory subsystem storing instruction information, and a separate memory subsystem storing data information. At design time, an address map is created implementing configurations of different ways of allocating instruction information and data information between memory blocks. At runtime, a configuration signal is received, and a particular memory block configuration for storing instruction information and data information is determined. An incoming instruction signal received from a dedicated microcontroller port, is communicated according to the configuration signal and the address map to a connection point (e.g., pin, fuse, register). Via that connection point, the instruction signal is routed to a memory block designated exclusively for instructions. Similarly, based upon the configuration signal and the address map, an incoming data signal (received from another dedicated microcontroller port), is routed via a connection point to a different memory block designated to store exclusively data information.