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

Setting up the DAC


The aim of this recipe is to echo the analog voltage input to the ADC to the DAC. The DAC operation is relatively simple as compared to the ADC. The MCBSTM400 evaluation board doesn't provide any means of directly monitoring either of the DAC channels. As DAC channel 2 (output to PA5) drives the clock for the USB 2.0 transceiver (IC6), the only option that we have is to use DAC channel 1 (output PA4). To see an output, we'll need to probe the output PA4 with a test meter. This recipe is called echo_adc_dac_c5v0.

How to do it…

To set up the DAC follow the steps outlined:

  1. Clone adcTimerISR_c5v0 from the Using timers to trigger conversions recipe and extend it by adding the dac.c and dac.h files. These will be used to define a function called DAC_Initialize() (shown next) that will be used to set up the DAC; the DAC registers and mask definitions are defined as a data structure in the stm32f4xx_hal.h file:

    #include ""stm32f4xx_hal.h""        /* STM32F4xx Defs */
    #include ""DAC...