Designing Embedded Systems with PIC Microcontrollers (eBook)

Cover 1
Copyright page 5
Table of contents 6
Introduction 22
Acknowledgements 26
Section 1: Getting Started with Embedded Systems 28
Chapter 1. Tiny computers, hidden control 30
1.1 The main idea – embedded systems in today’s world 30
1.2 Some example embedded systems 31
1.3 Some computer essentials 35
1.4 Microprocessors and microcontrollers 38
1.5 Microchip and the PIC microcontroller 42
1.6 An introduction to PIC microcontrollers using the 12 Series 44
1.7 What others do – a Freescale microcontroller 47
Summary 49
References 49
Section 2: Minimum Systems and the PIC 16F84A 50
Chapter 2. Introducing the PIC 16 Series and the 16F84A 52
2.1 The main idea – the PIC 16 Series family 52
2.2 An architecture overview of the 16F84A 54
2.3 A review of memory technologies 56
2.4 The 16F84A memory 59
2.5 Some issues of timing 64
2.6 Power-up and Reset 65
2.7 What others do – the Atmel AT89C2051 67
2.8 Taking things further – the 16F84A on-chip reset circuit 68
Summary 71
References 71
Chapter 3. Parallel ports, power supply and the clock oscillator 72
3.1 The main idea – parallel input/output 73
3.2 The technical challenge of parallel input/output 73
3.3 Connecting to the parallel port 79
3.4 The PIC 16F84A parallel ports 82
3.5 The clock oscillator 86
3.6 Power supply 88
3.7 The hardware design of the electronic ping-pong 90
Summary 91
References 91
Chapter 4. Starting to program – an introduction to Assembler 92
4.1 The main idea – what programs do and how we develop them 93
4.2 The PIC 16 Series instruction set, with a little more on the ALU 96
4.3 Assemblers and Assembler format 98
4.4 Creating simple programs 100
4.5 Adopting a development environment 103
4.6 An introductory MPLAB tutorial 104
4.7 An introduction to simulation 108
4.8 Downloading the program to a microcontroller 110
4.9 What others do – a brief comparison of CISC and RISC instruction sets 113
4.10 Taking things further – the 16 Series instruction set format 114
Summary 115
References 115
Chapter 5. Building Assembler programs 116
5.1 The main idea – building structured programs 116
5.2 Flow control – branching and subroutines 119
5.3 Generating time delays and intervals 122
5.4 Dealing with data 124
5.5 Introducing logical instructions 128
5.6 Introducing arithmetic instructions and the Carry flag 129
5.7 Taming Assembler complexity 133
5.8 More use of the MPLAB simulator 136
5.9 The ping-pong program 139
5.10 Simulating the ping-pong program – tutorial 143
5.11 What others do – graphical simulators 145
Summary 146
References 146
Chapter 6. Working with time: interrupts, counters and timers 147
6.1 The main idea – interrupts 148
6.2 Working with interrupts 152
6.3 The main idea – counters and timers 158
6.4 Applying the 16F84A Timer 0, with examples using the electronic ping-pong 163
6.5 TheWatchdog Timer 165
6.6 Sleep mode 166
6.7 What others do 167
6.8 Taking things further – interrupt latency 168
Summary 169
Section 3: Larger Systems and the PIC 16F873A 170
Chapter 7. Larger systems and the PIC 16F873A 172
7.1 The main idea – the PIC 16F87XA 173
7.2 The 16F873A block diagram and CPU 173
7.3 16F873A memory and memory maps 177
7.4 ‘Special’ memory operations 182
7.5 The 16F873A interrupts 185
7.6 The 16F873A oscillator, reset and power supply 188
7.7 The 16F873A parallel ports 188
7.8 Test, commission and diagnostic tools 192
7.9 The Microchip in-circuit debugger (ICD 2) 198
7.10 Applying the 16F873A: the Derbot AGV 199
7.11 Downloading, testing and running a simple program with ICD 2 203
7.12 Taking things further – the 16F874A/16F877A Ports D and E 207
Summary 209
References 210
Chapter 8. The human and physical interfaces 211
8.1 The main idea – the human interface 211
8.2 From switches to keypads 214
8.3 LED displays 220
8.4 Liquid crystal displays 226
8.5 The main idea – interfacing to the physical world 230
8.6 Some simple sensors 230
8.7 More on digital input 234
8.8 Actuators: motors and servos 239
8.9 Interfacing to actuators 242
8.10 Building up the Derbot 247
8.11 Applying sensors and actuators – a ‘blind’ navigation Derbot program 249
Summary 250
References 250
Chapter 9. Taking timing further 252
9.1 The main ideas – taking counting and timing further 252
9.2 The 16F87XA Timer 0 and Timer 1 253
9.3 The 16F87XA Timer 2, comparator and PR2 register 259
9.4 The capture/compare/PWM (CCP) modules 262
9.5 Pulse width modulation 264
9.6 Generating PWM in software 271
9.7 PWM used for digital-to-analog conversion 276
9.8 Frequency measurement 279
9.9 Speed control applied to the Derbot 282
9.10 Where there is no timer 285
9.11 Sleep mode 287
9.12 Where do we go from here? 288
9.13 Building up the Derbot 289
Summary 289
Reference 289
Chapter 10. Starting with serial 290
10.1 The main idea – introducing serial 290
10.2 Simple serial links – synchronous data communication 292
10.3 The 16F87XA Master Synchronous Serial Port (MSSP) module in SPI mode 294
10.4 A simple SPI example 300
10.5 The limitations of Microwire and SPI, and of simple synchronous serial transfer 302
10.6 Enhancing synchronous serial, and the Inter-Integrated Circuit bus 302
10.7 The MSSP configured for I2C 304
10.8 I2C applied in the Derbot AGV 313
10.9 Evaluation of synchronous serial data communication and an introduction to asynchronous 320
10.10 The 16F87XA Addressable Universal Synchronous Asynchronous Receiver Transmitter ( USART) 322
10.11 Implementing serial without a serial port – ‘bit banging’ 330
10.12 Building up the Derbot 330
Summary 330
References 330
Chapter 11. Data acquisition and manipulation 331
11.1 The main idea – analog and digital quantities, their acquisition and use 331
11.2 The data acquisition system 332
11.3 The PIC 16F87XA ADC module 339
11.4 Applying the ADC in the Derbot light meter program 346
11.5 Some simple data manipulation techniques 348
11.6 The Derbot light-seeking program 353
11.7 The comparator module 354
11.8 Applying the Derbot circuit for measurement purposes 356
11.9 Configuring the Derbot AGV as a light-seeking robot 359
Summary 359
References 359
Section 4: Smarter Systems and the PIC 18FXX2 360
Chapter 12. Smarter systems and the PIC 18FXX2 362
12.1 The main idea – the PIC 18 Series and the 18FXX2 363
12.2 The 18F2X2 block diagram and Status register 364
12.3 The 18 Series instruction set 367
12.4 Data memory and Special Function Registers 372
12.5 Program memory 374
12.6 The Stacks 379
12.7 The interrupts 380
12.8 Power supply and reset 385
12.9 The oscillator sources 387
12.10 Introductory programming with the 18F242 391
Summary 394
References 394
Chapter 13. The PIC 18FXX2 peripherals 395
13.1 The main idea – the 18FXX2 peripherals 395
13.2 The parallel ports 396
13.3 The timers 398
13.4 The capture/compare/PWM (CCP) modules 403
13.5 The serial ports 405
13.6 The analog-to-digital converter (ADC) 407
13.7 Low-voltage detect 407
13.8 Applying the 18 Series in the Derbot-18 409
13.9 The 18F2420 and the extended instruction set 410
Summary 412
Reference 412
Chapter 14. Introducing C 413
14.1 The main idea – why C? 414
14.2 An introduction to C 414
14.3 Compiling the C program 421
14.4 The MPLAB C18 compiler 422
14.5 A C18 tutorial 423
14.6 Simulating a C program 427
14.7 A second C example – the Fibonacci program 428
14.8 The MPLAB C18 libraries 430
14.9 Further reading 433
Summary 434
References 434
Chapter 15. C and the embedded environment 436
15.1 The main idea – adapting C to the embedded environment 436
15.2 Controlling and branching on bit values 436
15.3 More on functions 440
15.4 More branching and looping 442
15.5 Using the timer and PWM peripherals 444
Summary 449
Chapter 16. Acquiring and using data with C 450
16.1 The main idea – using C for data manipulation 450
16.2 Using the 18FXX2 ADC 450
16.3 Pointers, arrays and strings 458
16.4 Using the I2C peripheral 464
16.5 Formatting data for display 467
Summary 470
Chapter 17. More C and the wider C environment 471
17.1 The main idea – more C and the wider C environment 471
17.2 Assembler inserts 472
17.3 Controlling memory allocation 473
17.4 Interrupts 475
17.5 Example with interrupt on overflow – flashing LEDs on the Derbot 476
17.6 Storage classes and their application 480
17.7 Start-up code: c018i.c 483
17.8 Structures, unions and bit-fields 486
17.9 Processor-specific header files 487
17.10 Taking things further – the MPLAB Linker and the . map file 489
Summary 492
References 492
Chapter 18. Multi-tasking and the Real Time Operating System 493
18.1 The main ideas – the challenge of multi-tasking and real time 493
18.2 Achieving multi-tasking with sequential programming 496
18.3 The Real Time Operating System (RTOS) 499
18.4 Scheduling and the scheduler 500
18.5 Developing tasks 504
18.6 Data and resource protection – the semaphore 505
18.7 Where do we go from here? 506
Summary 506
References 506
Chapter 19. The SalvoTM Real Time Operating System 507
19.1 The main idea – Salvo, an example RTOS 507
19.2 Configuring the Salvo application 509
19.3 Writing Salvo programs 510
19.4 A first Salvo example 512
19.5 Using interrupts, delays and semaphores with Salvo 518
19.6 Using Salvo messages and increasing RTOS complexity 526
19.7 A program example with messages 527
19.8 The RTOS overhead 536
Summary 537
References 537
Section 5: Techniques of Connectivity and Networking 538
Chapter 20. Connectivity and networks 540
20.1 The main idea – networking and connectivity 540
20.2 Infrared connectivity 542
20.3 Radio connectivity 543
20.4 Controller Area Network (CAN) and Local Interconnect Network (LIN) 545
20.5 Embedded systems and the Internet 549
20.6 Conclusion 550
Summary 551
References 551
Appendix 1. The PIC 16 Series instruction set 554
Appendix 2. The electronic ping-pong 555
Appendix 3. The Derbot AGV – hardware design details 560
Appendix 4. Some basics of Autonomous Guided Vehicles 564
Appendix 5. PIC 18 Series instruction set (non-extended) 568
Appendix 6. Essentials of C 571
Index 576