Book Image

ARM® Cortex® M4 Cookbook

By : Mark Fisher, Dr. Mark Fisher
Book Image

ARM® Cortex® M4 Cookbook

By: Mark Fisher, Dr. Mark Fisher

Overview of this book

Embedded microcontrollers are at the core of many everyday electronic devices. Electronic automotive systems rely on these devices for engine management, anti-lock brakes, in car entertainment, automatic transmission, active suspension, satellite navigation, etc. The so-called internet of things drives the market for such technology, so much so that embedded cores now represent 90% of all processor’s sold. The ARM Cortex-M4 is one of the most powerful microcontrollers on the market and includes a floating point unit (FPU) which enables it to address applications. The ARM Cortex-M4 Microcontroller Cookbook provides a practical introduction to programming an embedded microcontroller architecture. This book attempts to address this through a series of recipes that develop embedded applications targeting the ARM-Cortex M4 device family. The recipes in this book have all been tested using the Keil MCBSTM32F400 board. This board includes a small graphic LCD touchscreen (320x240 pixels) that can be used to create a variety of 2D gaming applications. These motivate a younger audience and are used throughout the book to illustrate particular hardware peripherals and software concepts. C language is used predominantly throughout but one chapter is devoted to recipes involving assembly language. Programs are mostly written using ARM’s free microcontroller development kit (MDK) but for those looking for open source development environments the book also shows how to configure the ARM-GNU toolchain. Some of the recipes described in the book are the basis for laboratories and assignments undertaken by undergraduates.
Table of Contents (16 chapters)
ARM Cortex M4 Cookbook
Credits
About the Author
About the Reviewer
www.PacktPub.com
Preface
Index

Debugging assembly language


We can gain a useful insight into how assembly language instructions execute, and also why the compiler is rather poor at translating C using the debugger.

First, we'll compare a fragment of assembly language code produced by the compiler with our translation.

How to do it…

  1. Open the helloISR_c3v0 recipe that we introduced in the Handling interrupts recipe Chapter 3, C Language Programming.

  2. Insert a breakpoint adjacent to the first statement of the UART4_IRQHandler (that is, IIR = UART4->SR;).

  3. Select DebugStart/Stop Debug Session from the uVision5 pull-down menu.

  4. Run (F5) to the breakpoint (you will need to select the console window (PuTTY) and enter a character).

  5. uVision5 will now open a Disassembly window (illustrated in the following screenshot), which shows the assembly and machine code generated by the compiler for each C language statement.

How it works…

Some interesting observations from the disassembly are evident. First, by default, the compiler stores its...