ARM Assembly Language, 2nd Edition

Chapter 14

Exception Handling

ARM7TDMI

14.1 Introduction

Large applications, including operating systems, often have to deal with inputs from various sources, such as keyboards, mice, USB ports, and even power management blocks telling the processor its battery is about to run dry. Sometimes an embedded microcontroller has only one or two external input sources (e.g., from sensors in an engine), but it may still have peripheral devices that may need attention from time to time, such as a watchdog timer. Universal asynchronous receiver/transmitters (UARTs), wake-up alerts, analog-to-digital converters (ADCs), and I2C devices can all demand the processor’s time. In the next two chapters, we’re going to examine the different types of exceptions ...