First page Back Continue Last page Overview Graphics

Step 1. The Memory Map


To design a memory module, we need to specify first which addressable memory space is occupied by what types of memory chips. A mechanism used for this purpose is called a memory map. A memory map is usually a one-dimensional table. The size of the table does not exceed the microprocessor's addressable memory space. Each entry of the table corresponds to one memory location.

It is the duty of the computer system designer to specify what memory chip is allocated to what memory address. The rule for specifying the memory map is that different memory chips never occupy the same memory address. It is highly advisable that the starting address of each memory chip be an integer multiple of the addressable space of the chip. Following this advice can make the address decoding circuit simpler. This will be discussed in more detail later.