PIC32 Microcontrollers and the Digilent Chipkit

Introductory to Advanced Projects

Dogan Ibrahim

• Éditeur: Newnes
• Année: 2015
• ISBN:
  9780080999357
• Sujet: Conception
• Sous-sujet: Conception industrielle

PIC32 Microcontrollers and the Digilent chipKIT: Introductory to Advanced Projects will teach you about the architecture of 32-bit processors and the hardware details of the chipKIT development boards, with a focus on the chipKIT MX3 microcontroller development board. Once the basics are covered, the book then moves on to describe the MPLAB and MPIDE packages using the C language for program development. The final part of the book is based on project development, with techniques learned in earlier chapters, using projects as examples.

Each projectwill have a practical approach, with in-depth descriptions and program flow-charts with block diagrams, circuit diagrams, a full program listing and a follow up on testing and further development.

With this book you will learn:

• State-of-the-art PIC32 32-bit microcontroller architecture
• How to program 32-bit PIC microcontrollers using MPIDE, MPLAB, and C language
• Core features of the chipKIT series development boards
• How to develop simple projects using the chipKIT MX3 development board and Pmod interface cards
• how to develop advanced projects using the chipKIT MX3 development boards

• Demonstrates how to use the PIC32 series of microcontrollers in real, practical applications, and make the connection between hardware and software programming
• Usage of the PIC32MX320F128H microcontroller, which has many features of the PIC32 device and is included on the chipKIT MX3 development board
• Uses the highly popular chipKIT development boards, and the PIC32 for real world applications, making this book one of a kind

Chapter 1

Microcomputer Systems

Abstract

This chapter is an introduction to microcontrollers. The basic features of microcontrollers are described briefly with some typical application areas of microcontrollers.

Keywords

Microcontrollers

Microprocessors

Microcontroller features

Microcontroller applications

Chapter Outline

1.1 Introduction 2

1.2 Microcontroller Systems 2

1.2.1 RAM 5

1.2.2 ROM 6

1.2.3 PROM 6

1.2.4 EPROM 6

1.2.5 EEPROM 6

1.2.6 Flash EEPROM 7

1.3 Microcontroller Features 7

1.3.1 Supply Voltage 7

1.3.2 The Clock 7

1.3.3 Timers 8

1.3.4 Watchdog 8

1.3.5 Reset Input 8

1.3.6 Interrupts 8

1.3.7 Brown-Out Detector 9

1.3.8 Analogue-to-Digital Converter 9

1.3.9 Serial Input–Output 9

1.3.10 EEPROM Data Memory 10

1.3.11 LCD Drivers 10

1.3.12 Analogue Comparator 10

1.3.13 Real-Time Clock 10

1.3.14 Sleep Mode 10

1.3.15 Power-On Reset 11

1.3.16 Low-Power Operation 11

1.3.17 Current Sink/Source Capability 11

1.3.18 USB Interface 11

1.3.19 Motor Control Interface 11

1.3.20 CAN Interface 11

1.3.21 Ethernet Interface 11

1.3.22 ZigBee Interface 12

1.3.23 Multiply and Divide Hardware 12

1.3.24 Operating Temperature 12

1.3.25 Pulse Width Modulated (PWM) Outputs 12

1.3.26 JTAG Interface 12

1.3.27 Package Size 12

1.3.28 DMA 12

1.4 Microcontroller Architectures 12

1.4.1 RISC and CISC 13

1.5 8, 16, or 32 Bits? 13

1.6 Summary 14

1.7 Exercises 14

1.1. Introduction

The term microcomputer is used to describe a system that includes a minimum of a microprocessor, program memory, data memory, and input–output (I/O). Some microcomputer systems include additional components such as timers, counters, analogue-to-digital converters (ADCs), and so on. Thus, a microcomputer system can be anything from a large computer having hard disks, floppy disks, and printers to a single-chip embedded controller.

In this book, we are going to consider only the type of microcomputers that consists of a single silicon chip. Such microcomputer systems are also called microcontrollers, and they are used in many household goods such as microwave ovens, TV remote control units, cookers, hi-fi equipment, CD players, personal computers, fridges, etc. There are a large number of microcontrollers available in the market. In this book, we shall be looking at the programming and system design using the 32-bit programmable interface controller (PIC) series of microcontrollers manufactured by Microchip Technology Inc.

1.2. Microcontroller Systems

A microcontroller is a single-chip computer. Micro suggests that the device is small, and controller suggests that the device can be used in control applications. Another term used for microcontrollers is embedded controller, since most of the microcontrollers are built into (or embedded in) the devices they control.

A microprocessor differs from a microcontroller in many ways. The main difference is that a microprocessor requires several other components for its operation, such as program memory and data memory, I/O devices, and external clock circuit. A microcontroller, on the other hand, has all the support chips incorporated inside the same chip. All microcontrollers operate on a set of instructions (or the user program) stored in their memory. A microcontroller fetches the instructions from its program memory one by one, decodes these instructions, and then carries out the required operations.

Microcontrollers have traditionally been programmed using the assembly language of the target device. Although the assembly language is fast, it has several disadvantages. An assembly program consists of mnemonics, and it is difficult to learn and maintain a program written using the assembly language. Also, microcontrollers manufactured by different firms have different assembly languages and the user is required to learn a new language every time a new microcontroller is to be used. Microcontrollers can also be programmed using a high-level language, such as BASIC, PASCAL, and C. High-level languages have the advantage that it is much easier to learn a high-level language than an assembler. Also, very large and complex programs can easily be developed using a high-level language.

In general, a single chip is all that is required to have a running microcontroller system. In practical applications, additional components may be required to allow a microcomputer to interface to its environment. With the advent of the PIC family of microcontrollers, the development time of an electronic project has reduced to several hours.

Basically, a microcomputer (or microcontroller) executes a user program that is loaded in its program memory. Under the control of this program, data is received from external devices (inputs), manipulated, and then sent to external devices (outputs). For example, in a microcontroller-based fluid level control system, the fluid level is read by the microcomputer via a level sensor device and the microcontroller attempts to control the fluid level at the required value. If the fluid level is low, the microcomputer operates a pump to draw more fluid from the reservoir in order to keep the fluid at the required level. Figure 1.1 shows the block diagram of our simple fluid level control system.

Figure 1.1 Microcontroller-Based Fluid Level Control System

The system shown in Figure 1.1 is a very simplified fluid level control system. In a more sophisticated system, we may have a keypad to set the required fluid level and an LCD to display the current level in the tank. Figure 1.2 shows the block diagram of this more sophisticated fluid level control system.

Figure 1.2 Fluid Level Control System With a Keypad and LCD

We can make our design even more sophisticated (see Figure 1.3) by adding an audible alarm to inform us if the fluid level is outside the required value. Also, the actual level at any time can be sent to a PC every second for archiving and further processing. For example, a graph of the daily fluid level changes can be plotted on the PC. As you can see, because the microcontrollers are programmable, it is very easy to make the final system as simple or as complicated as we like.

Figure 1.3 More Sophisticated Fluid Level Controller

A microcontroller is a very powerful tool that allows a designer to create sophisticated I/O data manipulation under program control. Microcontrollers are classified by the number of bits they process. 8-bit devices are the most popular ones and are used in most low-cost, low-speed microcontroller-based applications. 16- and 32-bit microcontrollers are much more powerful, but usually more expensive, and their use may not be justified in many small- to medium-sized general-purpose applications.

The simplest microcontroller architecture consists of a microprocessor, memory, and I/O. The microprocessor consists of a central processing unit (CPU) and the control unit (CU). The CPU is the brain of the microcontroller, and this is where all of the arithmetic and logic operations are performed. The CU controls the internal operations of the microprocessor and sends out control signals to other parts of the microcontroller to carry out the required instructions.

Memory is an important part of a microcontroller system. Depending on the type used, we can classify memories into two groups: program memory and data memory. Program memory stores the programs written by the programmer, and this memory is usually nonvo...