A microcontroller can be found at the heart of almost any automotive electronic control module or ECU in production today. Automotive systems such as antilock braking control (ABS), engine control, navigation, and vehicle dynamics all incorporate at least one microcontroller within their ECU to perform necessary control functions. Understanding the various features and offerings of microcontrollers that are available on the market today is important when making a selection for an application. This chapter is intended to provide a look at various microcontroller features and provide some insight into their characteristics from an automotive application point of view.

11.1 Microcontroller Architecture and Performance Characteristics

A microcontroller can essentially be thought of as a single-chip computer system and is often referred to as a single-chip microcomputer. It detects and processes input signals, and responds by asserting output signals to the rest of the ECU. Fabricated upon this highly integrated, single piece of silicon are all of the features necessary to perform embedded control functions. Microcontrollers are fabricated by many manufacturers and are offered in just about any imaginable mix of memory, I/O, and peripheral sets. The user customizes the operation of the microcontroller by programming it with his or her own unique program. The program configures the microcontroller to detect external events, manipulate the collected data, and respond with appropriate output. The user's program is commonly referred to as code and typically resides on-chip in either ROM or EPROM. In some cases where...