Designing Embedded Hardware, 2nd Edition

Chapter 12. Networks

Never let the future disturb you. You will meet it, if you have to, with the same weapons of reason that today arm you against the present.

—Marcus Aurelius Antoninus, Meditations

No town or freeman shall be compelled to build bridges ... except those with an ancient obligation to do so.

— —The Magna Carta

In this chapter, we'll look at connecting your embedded computer to the real world by adding a Local Area Network (LAN) interface. There is a wide variety of networks employed—some very common, some not so common. We'll take a look at CAN and Ethernet, the two most common networks. CAN is a network for industrial applications, where a conventional network just won't do. CAN is suited to electrically noisy and harsh conditions and is the network of choice in electrically severe environments. Ethernet is the intranet network that connects the world's desktop computers, as well as a host of other devices such as routers, gateways, printers, and other peripherals.

Controller Area Network (CAN)

Through the late 70s and 80s, the complexity of automotive electronics grew considerably, with engine-management systems, ABS braking, active suspension, electronic transmissions, automated lighting, air-conditioning, security, and central locking. Each of these systems does not exist in isolation but is part of an integrated whole. A considerable amount of information exchange is required, and, therefore, some means of system interconnection must be provided. ...