Elliot Williams - Make: AVR Programming: Learning to Write Software for Hardware

And so we come to my sincerest goal in writing this book instead of simplyanother blinky-LEDs-on-an-Arduino manualto turn you into a truemicrocontroller type. Although the Arduino environment is good for getting peoplehooked on microcontrollers, its a cheap high. Arduino/Wiring goes to greatlengths to abstract away from the microcontrollers hardware. Here, I want toteach you about the hardware because its usefulso getting further awayfrom it wont help. (My friend Ash once described working with the Arduinoenvironment as being like knitting in boxing gloves.)

I dont think that the built-in hardware timer modules are something to beabstracted away from. I believe the timers should be understood thoroughlyenough to be abused to create a small AM radio transmitter that can play theMario theme song within a room using nothing more than a wire or your finger asan antenna (in

More seriously, many of the hardware peripherals inside the AVR arecommon to most microcontrollers, from the prehistoric 8051 or the tiniest PICor ATtiny chips, through the MSP430s and the ATmegas, to the mighty XMega andARM chips. These hardware peripherals have been developed and honed over 40years of microcontroller design development, and theyre not going away any timesoon because they have been designed to be helpful to getting your projectrealized. The microcontroller hardware has been designed by very cleverengineers to solve your problems. My goal in writing this book is to show youhow common problems are solved. You need to learn thehardware, and apply the hardware, to love the hardware.

Although every microcontroller design implements things a littlebit differently, once youve seen it here, it will make sense there. Everymicrocontroller that Ive ever come across is programmable in C. Almost all of what you learn workingthrough this book is transferrable to other chips and other architectures,because what youre learning here is the way things work rather than anabstraction wrapped around the way things work, designed to protect you from theway things work. Some of what you learn (for instance bitwise binary manipulations in )might seem boring, but in the end it will give you simple and direct access tothe common hardware bits that are put there to help you, and the techniques willwork with any brand of microcontroller that you choose to use.

In short, almost none of the time you spend learning about how to createprojects on the AVR in C will be wasted. Yeah, its a bit harder than justreusing someones shields and code. Yeah, you might need to stop sometimes andleaf through a C programming book or an electronics text (or just look it up onthe Net). But when you find out that you need more processing power, or adifferent set of peripherals, you can just buy yourself a $8 chipin place of the $4 one you were using and bring most of your code, and moreimportantly your knowledge, along with you.

This book is meant to be the red pill, and I sincerely hope that you find itworth your time once youve seen how deep the rabbit hole goes.

Before we get too much into detail about the AVR chips and what they can do foryou, let me provide you with a shopping list. Order this stuff now so that youcan be ready to start programming chips in a few days when the delivery truckshows up.