Programming the Finite State Machine with 8-Bit PICs in Assembly and C

Table of Contents

• Preface
• Chapter 1: Getting Started
  • 1.1 Introduction
  • 1.2 Practical Implementation
    • 1.2.1 Choice of Operating System
    • 1.2.2 Machine Language and Assembly Source Files
    • 1.2.3 Using the Applications on Microsoft Windows
    • 1.2.4 Installing the Applications on Linux
    • 1.2.5 The FTDI Lead and Testing the Programming Chain
  • 1.3 Some Fundamentals
    • 1.3.1 Bits and Bytes
    • 1.3.2 The Hexadecimal Numbering System
    • 1.3.3 Boolean Logic
    • 1.3.4 Bitwise logic
    • 1.3.5 PIC Architecture
    • 1.3.6 Data Memory Organization
    • 1.3.7 An Assembly Program Snippet
  • 1.4 Program Memory
  • 1.5 Hello World
    • 1.5.1 Some Key Points
    • 1.5.2 Assembling the Program
• Chapter 2: The Assembly Program as a Finite State Machine
  • 2.1 Introduction
  • 2.2 A State Machine Framework for Assembly Language
  • 2.3 Timer0
  • 2.4 Interrupts
  • 2.5 A More Complicated LED Flasher
  • 2.6 Running More Than One Machine in a Program
  • 2.7 Driving a Seven Segment LED Display
  • 2.8 The Differences Between the PIC 12F1822 and the 16F1823
  • 2.9 Interrupts and State Diagrams
• Chapter 3: Macros, Subroutines and Bank Switching
  • 3.1 Introduction
  • 3.2 Create Your Own Instruction
    • 3.2.1 Use an Include File
    • 3.2.2 More Macros
    • 3.2.3 Conditional Assembly
  • 3.3 Subroutines
    • 3.3.1 An Example of a Subroutine
    • 3.3.2 Return Address and the Stack
    • 3.3.3 Calculating the Delay
    • 3.3.4 Calling Subroutines from Subroutines
  • 3.4 Bank Switching
• Chapter 4: Inputs and Outputs
  • 4.1 Introduction
  • 4.2 Serial Output to a Computer
    • 4.2.1 TTL Level Serial Communications
    • 4.2.2 Configuring the EUSART to Transmit a Byte
    • 4.2.3 Serial Output Example
  • 4.3 Serial Input from a Computer
    • 4.3.1 Configuring the EUSART to Receive Bytes
    • 4.3.2 Interrupt Service Routine
    • 4.3.3 Serial Input Example
  • 4.4 Analog Inputs
    • 4.4.1 Setting ADCON0 and ADCON1
    • 4.4.2 Circuit and State Diagram
  • 4.5 Pulse with modulated outputs
    • 4.5.1 LED with Pulsing Brightness
  • 4.6 Digital Inputs
    • 4.6.1 Counting Input Pulses From a Switch
    • 4.6.2 First method eliminating the effect of switch bounce
    • 4.6.3 A Better Method of Eliminating the Effect of Switch Bounce
• Chapter 5: Project Hardware Construction
  • 5.1 Introduction
  • 5.2 Overview of the Suggested Method
  • 5.3 Cutting and Drilling the board
  • 5.4 Populating and Wiring the Board
  • 5.5 The Circuit Board Test Program
    • 5.5.1 Analog Configuration
• Chapter 6: Binary Arithmetic
  • 6.1 Introduction
  • 6.2 Binary Addition of Unsigned Numbers
    • 6.2.1 Adding Two Eight Bit Positive Integers
    • 6.2.2 Serial Read Program Command Line Arguments
    • 6.2.3 Adding Two Sixteen Bit Positive Numbers
  • 6.3 Binary Subtraction of unsigned integers
  • 6.4 Binary Subtraction with Negative Results
  • 6.5 Negative numbers in binary
  • 6.6 Binary Multiplication
  • 6.7 Binary Division
• Chapter 7: Digital Voltmeter Project
  • 7.1 Introduction
  • 7.2 The State Diagrams
  • 7.3 Scaling the Raw Analog Value
  • 7.4 Extracting the individual figures for the display
  • 7.5 Detecting No Input Voltage
  • 7.6 Recalibration
• Chapter 8: Troubleshooting and Planning
  • 8.1 Introduction
  • 8.2 Have an Overview of the Project
    • 8.2.1 State Diagrams and Flow Charts
  • 8.3 Break Big Problems Down Into Smaller Ones
  • 8.4 Read Through Your Code in Detail and Add Comments
  • 8.5 Debugging a Running Program
  • 8.6 Traffic Lights
    • 8.6.1 A Circuit Diagram
    • 8.6.2 Separate Different Problems
    • 8.6.3 Producing the Code
  • 8.7 Using Debug Macro on the Voltmeter Programmable
  • 8.8 A List of Things to Remember
• Chapter 9: A Comparison with C
  • 9.1 Introduction
  • 9.2 The Microchip XC8 Compiler
    • 9.2.1 XC8 for Microsoft Windows
    • 9.2.2 XC8 for 32 Bit Debian-Based Distributions
    • 9.2.3 XC8 for 64 Bit Debian-Based Distributions
    • 9.2.4 XC8 for 64-Bit Fedora
  • 9.3 Introduction to C
    • 9.3.1 Hello World in C
    • 9.3.2 Using the XC8 Compiler in Microsoft Windows
    • 9.3.3 Using the XC8 Compiler in Linux
    • 9.3.4 Emitted Code Assembly vs C
    • 9.3.5 Interrupts in C
    • 9.3.6 The _delay() functions
    • 9.3.7 Extending the If Statement
    • 9.3.8 The Switch Statement
    • 9.3.9 An Experiment to Measure Code Speed
  • 9.4 Serial Communication
    • 9.4.1 Serial Byte Transmission
    • 9.4.2 Serial Byte Reception
• Chapter 10: Further C
  • 10.1 Introduction
  • 10.2 Data Types
  • 10.3 More on Functions
  • 10.4 Integer Arithmetic
    • 10.4.1 Transmitting a Four-Byte Integer
    • 10.4.2 The "for" loop
  • 10.5 The Voltmeter in C
    • 10.5.1 Turning Bits On and Off Using Bit Type
    • 10.5.2 Turning Bits On and Off Using Bitwise Operators
    • 10.5.3 Turning Bits On and Off Using Bitfields
  • 10.6 Summary of Assembly, C, and Finite State Machines
• Index

Chapter 1: Getting Started

This chapter introduces the fundamental concepts required for programming 8-bit PIC microcontrollers, focusing on the practical aspects of setting up the development environment and understanding basic programming constructs.

1.1 Introduction

Provides an overview of the book's scope and the importance of finite state machines in embedded systems.

1.2 Practical Implementation

Details the practical steps involved in implementing finite state machines on PIC microcontrollers.

1.2.1 Choice of Operating System

Discusses the considerations for choosing an operating system for microcontroller development, including options like Microsoft Windows and Linux.

1.2.2 Machine Language and Assembly Source Files

Explains the difference between machine language and assembly language, and the structure of assembly source files.

1.2.3 Using the Applications on Microsoft Windows

Guides users on utilizing development tools and applications within the Microsoft Windows environment.

1.2.4 Installing the Applications on Linux

Provides instructions for installing and configuring development tools on Linux-based systems.

1.2.5 The FTDI Lead and Testing the Programming Chain

Covers the use of FTDI leads for programming PIC microcontrollers and testing the overall programming chain.

1.3 Some Fundamentals

Covers essential foundational knowledge for microcontroller programming.

1.3.1 Bits and Bytes

Explains the basic units of digital information: bits and bytes, and their representation.

1.3.2 The Hexadecimal Numbering System

Details the hexadecimal numbering system and its application in programming.

1.3.3 Boolean Logic

Introduces the principles of Boolean logic, including AND, OR, and NOT operations.

1.3.4 Bitwise Logic

Explains bitwise operations such as AND, OR, XOR, and bit shifting.

1.3.5 PIC Architecture

Provides an overview of the architecture of PIC microcontrollers.

1.3.6 Data Memory Organization

Describes how data is organized and stored in the memory of PIC microcontrollers.

1.3.7 An Assembly Program Snippet

Presents a small example of an assembly language program for PIC microcontrollers.

1.4 Program Memory

Discusses the structure and usage of program memory in PIC microcontrollers.

1.5 Hello World

Introduces a basic "Hello World" program as a starting point for learning.

1.5.1 Some Key Points

Highlights important considerations for the "Hello World" program.

1.5.2 Assembling the Program

Explains the process of assembling the "Hello World" program.

Chapter 2: The Assembly Program as a Finite State Machine

This chapter focuses on implementing finite state machines using assembly language programming for PIC microcontrollers.

2.1 Introduction

Introduces the concept of using assembly language to create finite state machines.

2.2 A State Machine Framework for Assembly Language

Presents a structured framework for building state machines in assembly code.

2.3 Timer0

Explains the functionality and usage of the Timer0 peripheral in PIC microcontrollers.

2.4 Interrupts

Covers the concept of interrupts and how they are handled in assembly programs.

2.5 A More Complicated LED Flasher

Details the creation of a more complex LED flasher program using state machines.

2.6 Running More Than One Machine in a Program

Discusses techniques for managing multiple state machines within a single program.

2.7 Driving a Seven Segment LED Display

Explains how to control a seven-segment LED display using assembly language.

2.8 The Differences Between the PIC 12F1822 and the 16F1823

Highlights the key differences between the PIC 12F1822 and PIC 16F1823 microcontrollers.

2.9 Interrupts and State Diagrams

Explores the relationship between interrupts and state diagrams in program design.

Chapter 3: Macros, Subroutines and Bank Switching

This chapter delves into advanced assembly programming techniques, including macros, subroutines, and bank switching.

3.1 Introduction

Introduces the topics of macros, subroutines, and bank switching in assembly programming.

3.2 Create Your Own Instruction

Explains how to create custom instructions or macros to simplify coding.

3.2.1 Use an Include File

Demonstrates the use of include files to organize and reuse code.

3.2.2 More Macros

Covers the creation and usage of more complex macros.

3.2.3 Conditional Assembly

Explains how to use conditional assembly directives to control code compilation.

3.3 Subroutines

Details the concept and implementation of subroutines (functions) in assembly language.

3.3.1 An Example of a Subroutine

Provides a practical example of creating and using a subroutine.

3.3.2 Return Address and the Stack

Explains how the stack is used to manage subroutine calls and return addresses.

3.3.3 Calculating the Delay

Shows methods for calculating and implementing delays in assembly programs.

3.3.4 Calling Subroutines from Subroutines

Demonstrates how to nest subroutine calls.

3.4 Bank Switching

Explains the concept of bank switching for accessing memory in PIC microcontrollers.

Chapter 4: Inputs and Outputs

This chapter covers how to interface PIC microcontrollers with external devices through various input and output methods.

4.1 Introduction

Introduces the chapter's focus on input and output operations.

4.2 Serial Output to a Computer

Details how to send data from a PIC microcontroller to a computer via serial communication.

4.2.1 TTL Level Serial Communications

Explains the principles of TTL level serial communication.

4.2.2 Configuring the EUSART to Transmit a Byte

Guides on configuring the EUSART (Enhanced Universal Synchronous/Asynchronous Receiver/Transmitter) module for transmitting data.

4.2.3 Serial Output Example

Provides an example of a program that outputs data serially.

4.3 Serial Input from a Computer

Covers receiving data from a computer to a PIC microcontroller via serial communication.

4.3.1 Configuring the EUSART to Receive Bytes

Details the configuration of the EUSART module for receiving data.

4.3.2 Interrupt Service Routine

Explains the use of interrupt service routines for handling serial data reception.

4.3.3 Serial Input Example

Provides an example of a program that receives data serially.

4.4 Analog Inputs

Discusses how to read analog signals using the PIC microcontroller's Analog-to-Digital Converter (ADC).

4.4.1 Setting ADCON0 and ADCON1

Explains the configuration of the ADCON0 and ADCON1 registers for ADC operation.

4.4.2 Circuit and State Diagram

Presents a circuit diagram and state diagram related to analog input processing.

4.5 Pulse with modulated outputs

Covers generating modulated pulse outputs.

4.5.1 LED with Pulsing Brightness

Details how to control an LED's brightness using pulse width modulation (PWM).

4.6 Digital Inputs

Explains how to read digital signals from external sources.

4.6.1 Counting Input Pulses From a Switch

Demonstrates how to count pulses generated by a switch.

4.6.2 First method eliminating the effect of switch bounce

Presents a method for debouncing a mechanical switch.

4.6.3 A Better Method of Eliminating the Effect of Switch Bounce

Offers an improved technique for switch debouncing.

Chapter 5: Project Hardware Construction

This chapter provides guidance on constructing the hardware for projects discussed in the book.

5.1 Introduction

Introduces the hardware construction phase of the projects.

5.2 Overview of the Suggested Method

Outlines the recommended approach for building the project hardware.

5.3 Cutting and Drilling the board

Provides instructions for preparing the printed circuit board (PCB).

5.4 Populating and Wiring the Board

Details the process of placing components and making connections on the PCB.

5.5 The Circuit Board Test Program

Describes a test program to verify the functionality of the constructed circuit board.

5.5.1 Analog Configuration

Explains the analog configuration required for the test program.

Chapter 6: Binary Arithmetic

This chapter covers various arithmetic operations performed using binary numbers, relevant to microcontroller programming.

6.1 Introduction

Introduces the topic of binary arithmetic.

6.2 Binary Addition of Unsigned Numbers

Explains how to perform addition with unsigned binary numbers.

6.2.1 Adding Two Eight Bit Positive Integers

Demonstrates the addition of two 8-bit positive integers.

6.2.2 Serial Read Program Command Line Arguments

Discusses reading program command line arguments serially.

6.2.3 Adding Two Sixteen Bit Positive Numbers

Shows how to add two 16-bit positive integers.

6.3 Binary Subtraction of unsigned integers

Explains the process of subtracting unsigned binary numbers.

6.4 Binary Subtraction with Negative Results

Covers binary subtraction that results in negative numbers.

6.5 Negative numbers in binary

Discusses different methods for representing negative numbers in binary, such as two's complement.

6.6 Binary Multiplication

Explains the algorithms for binary multiplication.

6.7 Binary Division

Covers the algorithms for binary division.

Chapter 7: Digital Voltmeter Project

This chapter details a project to build a digital voltmeter using PIC microcontrollers.

7.1 Introduction

Introduces the digital voltmeter project.

7.2 The State Diagrams

Presents the state diagrams that define the operation of the digital voltmeter.

7.3 Scaling the Raw Analog Value

Explains how to scale the raw analog readings from the ADC to represent voltage values.

7.4 Extracting the individual figures for the display

Details the process of extracting individual digits for display on an output device.

7.5 Detecting No Input Voltage

Describes methods for detecting when there is no input voltage.

7.6 Recalibration

Covers the process of recalibrating the digital voltmeter for accuracy.

Chapter 8: Troubleshooting and Planning

This chapter provides guidance on troubleshooting common issues and planning microcontroller projects.

8.1 Introduction

Introduces the topics of troubleshooting and project planning.

8.2 Have an Overview of the Project

Emphasizes the importance of having a clear understanding of the project's goals and structure.

8.2.1 State Diagrams and Flow Charts

Discusses the use of state diagrams and flow charts in project planning and debugging.

8.3 Break Big Problems Down Into Smaller Ones

Advises on a systematic approach to problem-solving by breaking down complex issues.

8.4 Read Through Your Code in Detail and Add Comments

Stresses the importance of code readability and documentation through detailed review and commenting.

8.5 Debugging a Running Program

Offers techniques for debugging programs that are currently running on the microcontroller.

8.6 Traffic Lights

Uses a traffic light simulation as a case study for troubleshooting and implementation.

8.6.1 A Circuit Diagram

Presents a circuit diagram for the traffic light project.

8.6.2 Separate Different Problems

Discusses isolating and addressing different issues within the project.

8.6.3 Producing the Code

Covers the process of generating the final code for the traffic light system.

8.7 Using Debug Macro on the Voltmeter Programmable

Explains how to use debug macros with the voltmeter project.

8.8 A List of Things to Remember

Provides a summary of key points and best practices.

Chapter 9: A Comparison with C

This chapter compares programming in Assembly language with programming in C for PIC microcontrollers.

9.1 Introduction

Introduces the comparison between Assembly and C programming.

9.2 The Microchip XC8 Compiler

Discusses the Microchip XC8 compiler, a C compiler for PIC microcontrollers.

9.2.1 XC8 for Microsoft Windows

Details the usage of XC8 on the Windows platform.

9.2.2 XC8 for 32 Bit Debian-Based Distributions

Covers XC8 installation and usage on 32-bit Debian-based Linux systems.

9.2.3 XC8 for 64 Bit Debian-Based Distributions

Covers XC8 installation and usage on 64-bit Debian-based Linux systems.

9.2.4 XC8 for 64-Bit Fedora

Details XC8 usage on 64-bit Fedora Linux systems.

9.3 Introduction to C

Provides an introduction to the C programming language for embedded systems.

9.3.1 Hello World in C

Presents a "Hello World" program written in C.

9.3.2 Using the XC8 Compiler in Microsoft Windows

Explains how to use the XC8 compiler within the Windows environment.

9.3.3 Using the XC8 Compiler in Linux

Guides on using the XC8 compiler on Linux systems.

9.3.4 Emitted Code Assembly vs C

Compares the assembly code generated by the C compiler with hand-written assembly.

9.3.5 Interrupts in C

Discusses how to handle interrupts using C programming.

9.3.6 The _delay() functions

Explains the use of delay functions in C.

9.3.7 Extending the If Statement

Covers advanced usage of the 'if' statement in C.

9.3.8 The Switch Statement

Details the 'switch' statement for multi-way branching.

9.3.9 An Experiment to Measure Code Speed

Describes an experiment to measure the execution speed of C code.

9.4 Serial Communication

Covers serial communication protocols in C.

9.4.1 Serial Byte Transmission

Explains how to transmit data byte by byte serially in C.

9.4.2 Serial Byte Reception

Details how to receive data byte by byte serially in C.

Chapter 10: Further C

This chapter explores more advanced C programming concepts relevant to PIC microcontroller development.

10.1 Introduction

Introduces additional C programming topics.

10.2 Data Types

Discusses various data types available in C and their usage.

10.3 More on Functions

Covers advanced aspects of function definition and usage in C.

10.4 Integer Arithmetic

Explains integer arithmetic operations in C.

10.4.1 Transmitting a Four-Byte Integer

Demonstrates how to transmit a 4-byte integer value.

10.4.2 The "for" loop

Explains the usage of the 'for' loop for iterative tasks.

10.5 The Voltmeter in C

Details the implementation of the digital voltmeter project using C programming.

10.5.1 Turning Bits On and Off Using Bit Type

Shows how to manipulate individual bits using bit types.

10.5.2 Turning Bits On and Off Using Bitwise Operators

Explains the use of bitwise operators for bit manipulation.

10.5.3 Turning Bits On and Off Using Bitfields

Covers the use of bitfields for efficient data packing.

10.6 Summary of Assembly, C, and Finite State Machines

Provides a summary comparing Assembly, C, and finite state machine concepts.

Index

An index of terms and topics covered in the book.