Digital Interface Design and Application

1 Review of Digital Electronics and Computer Architecture

This chapter will focus on the operation of basic logic elements, which should be familiar to most readers, such as flip/flops and registers that form the basic building blocks for interface elements. It will also cover the issue of address decoding to enable these elements through a programme statement and provide an introduction to the ARM architecture and its built-in peripherals. Finally the linkage between C and low-level assembler code will be shown through a simple example.

1.1 Embedded Systems

Embedded systems take many different forms but all rely on some computing processor whether it has a physical interface with the outside world like the keyboard and screen of a typical PC, the physical connections forming a communication network or specialised sensor and actuator hardware to control an automated machine. The other essential element of any system making use of a computer is its controlling program and in fact most embedded system component vendors provide integrated development systems or environments (IDE) that run on a PC to facilitate the software development. Interface design requires careful assessment of both the hardware and software requirements so that when the objectives are considered the most effective solution can be achieved. In summary, we can say that an embedded system is computerised and tailor-made for a particular application.

1.1.1 Processor Architecture (Revision)

It is important ...