C251 User's Guide

Memory Areas

The MCS® 251 architecture supports several physically separate memory areas or memory spaces for program and data. Each memory area offers certain advantages and disadvantages. There are memory spaces that may be:

• read from but not written to.
• read from or written to.
• read from or written to more quickly than other memory spaces.

The wide variety of memory space available on the MCS® 251 is quite different from most mainframe, minicomputer, and microcomputer architectures where the program, data, and constants are all loaded into the same physical memory space within the computer. Refer to the Intel MCS® 251 Embedded Microcontrollers data book or other 251 data books for more information about the MCS® 251 memory architecture.