Programming Embedded Systems in C and C++

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Chapter 6

In this chapter:

• Types of Memory

• Memory Testing

• Validating Memory

Contents

• Working with Flash

Memory

6

6. Memory

Tyrell: If we give them a past, we create a cushion for their

emotions and, consequently, we can control them better.

Deckard: Memories. You’re talking about memories.

— the movie Blade Runner

In this chapter, you will learn everything you need to know about memory in

embedded systems. In particular, you will learn about the types of memory you

are likely to encounter, how to test memory devices to see if they are working

properly, and how to use Flash memory.

Types of Memory

Many types of memory devices are available for use in modern computer systems.

As an embedded software engineer, you must be aware of the differences between

them and understand how to use each type effectively. In our discussion, we will

approach these devices from a software viewpoint. As you are reading, try to keep

in mind that the development of these devices took several decades and that there

are significant physical differences in the underlying hardware. The names of the

memory types frequently reflect the historical nature of the development process

and are often more confusing than insightful.

Most software developers think of memory as being either random-access (RAM)

or read-only (ROM). But, in fact, there are subtypes of each and even a third class

of hybrid memories. In a RAM device, the ...