Memory map rules enable you to control how memory map blocks are displayed. Typically, map rules are required when multiple memory map blocks are defined that occupy the same area of memory, but only one of the blocks is to be active at a time. For example, when a target supports memory remapping. These memory map blocks are referred to as controlled memory map blocks.

The active memory map block is determined by examining the value of a custom register or peripheral register. There must be a map rule for each memory map block that is to be controlled by that register. Each map rule associates a unique register value with a specific memory map block.