This guide is intended to help beginners to start off programming ARM microcontroller based systems. The material of this book describes ARM interfacing and programming techniques using Proteus VSM – the most complete and powerful simulator on the market. Proteus VSM for ARM7 allows to develop, test and virtually prototype embedded system designs based around the popular Phillips LPC21xx microcontrollers, so the readers don’t need any hardware to start off learning ARM programming and interfacing. The most exciting and important feature of Proteus VSM is its ability to simulate the interaction between software running on a microcontroller and any analog or digital electronic circuits connected to it. Besides learning the programming techniques, this guide provides the description of complete designs of several simple measurement and control systems which include various electronic components (temperature sensors, comparators, transistors, LEDs, DC motors, digital potentiometers and digital-to-analog converters). The readers may evolve their projects extremely fast, as the microcontroller component and the additional electronic parts may be quickly dropped on the screen and a program code may be attached to a project instantly. All projects described in this guide may be easily improved or modified in minutes if necessary. Volume 1 concerns the development of applications with Timers, GPIO, Analog-To-Digital and Digital-To-Analog converters.The material of this guide is based on Proteus VSM 7.8 and Keil MDK–ARM development systems. All applications are written in C/C++ using a free Keil MDK-Lite v.4.21 development environment that allows to generate up to 32KB code – it is quite enough for the development of simple applications. All projects from this guide are built around the LPC2138 ARM microcontroller.