In this chapter, we see that schedulers can play a similar role in embedded systems to that played by ‘Windows’ (or other operating systems) in many modern desktop applications.
Introduction
Having laid the foundations in Parts A and B, we are now in a position to look in detail at the ways in which time-triggered applications may be created with the 8051 family of microcontrollers.
To produce such applications, we will use a scheduler: this is a very simple operating environment for embedded applications. In this introductory chapter, we explain what a scheduler is and the differences between co-operative and pre-emptive scheduling. We will also explain why the use of a co-operative scheduler can help to make even the smallest of embedded applications easier to develop and more reliable in operation.
To place the discussions in the rest of the chapter in context, we begin by briefly reviewing the reasons why desktop systems employ an operating system and explain- ing why such an OS is not appropriate for use with the type of embedded systems considered in this book.