I was studying about the memory of the dpsic30f family microchip. In general also i am finding that there is lot of reserved memory why is it so? Is it a kind of wastage or they are not able to use it? I don't understand this.
I bet it is used for something if it is reserved. Where is this memory area that is reserved? Is it sram or flash? Usually part of the sram is reserved for peripheral registers etc. Then the freely usable memory space comes after that. Do you have a datasheet page where you found this information you are referring to? Is there some sort of memory that is not accessible?
Modern microcontroller memories are designed for C programming language. You can easily map C-structures directly to peripheral registers etc. Even the instruction sets are designed for C compilers.
Ok. I get it. When they design a peripheral, they need to assign registers to control the peripheral. It is smart to leave some gaps between different peripheral register for future use. If they need to add some functionality, they can use the unused memory near the existing registers and they do not need to move around and mess with registers assigned to other peripherals.