Introduction to Embedded Systems

Transcription

1 Introduction to Embedded Systems UsingANSICand the Arduino Development Environment David J. Russell University of NebraskaLincoln SYNTHESIS LECTURES ONDIGITAL CIRCUITSAND SYSTEMS #30

2 xi Preface Introduction xix Background Digital Representation of Information Digital Logic Fundamentals Digital Vectors Information Representation in a Digital Processor Numbers Text 9 17 ANSIC Introduction Background Essential Elements of the Language Formatted Output Variables and Arithmetic Expressions Variable Names Type Conversions Constants Arithmetic Operators Relational and Logical Operators Increment and Decrement Operators Bitwise Operators Assignment Operators Conditional Expression Control Flow IfElse ElseIf Switch Loops 46

3 2.5.5 Infinite Loops Miscellaneous (Please Don't Use) Functions and Program Structures Scope Rules Pointers and Arrays Passing by Reference Dynamic Memory Allocation Multidimensional Arrays Function Pointers Structures Typedef Unions Bitfields Variablelength Argument Lists 76 3 Introduction to Arduino Background Experiments Using the Arduino Duemilanove Development Board Arduino Tools Tutorial 81 4 Embedded Debugging Introduction Debugging the Arduino Tutorial 89 5 ATmega328P Architecture Overview AVR CPU Core 96 6 GeneralPurpose Input/Output Output Introduction Basic Operation muxing Input Introduction Internal Pullup Resistor 104

4 The The Output Timer/CounterO Timer/Counter Input Output Output 6.3 Accessing GPIO lines in C Managing Outputs Managing Inputs 6.4 Pertinent Register Descriptions PORTB DDRB PINB 106 Port B Data Register 108 The Port B Data Direction Register 108 Port B Input s Address PORTCThe Port C Data Register DDRC PINC The Port C Data Direction Register 108 The Port C Input s Address PORTDThe Port D Data Register DDRD PIND The Port D Data Direction Register 109 The Port D Input s Address 109 xiii 7 Timer Ports Pulse Width Modulation Introduction Demodulation Modulation Input Capture 7.3 Pertinent Register Descriptions TCCR0A TCCR0B 119 Timer/CounterO Control Register A 120 Control Register B TCNT0Timer/CounterO Register OCR0A CompareO Register A OCR0B Output CompareO Register B TCCR1A TCCR1B TCCR1C 1 Control Register A 123 Timer/Counterl Control Register B 125 Timer/Counterl Control Register C TCNT1H andtcnt1ltimer/counterl Register OCR1AH and OCR1AL OCR1BH and OCR1BL ICR1H and ICR1L Comparel Register A 127 Comparel Register B 128 Capturel Register TCCR2ATimer/Counter2 Control Register A TCCR2B Timer/Counter2 Control Register B TCNT2Timer/Counter2 Register OCR2A Output Compare2 Register A 132

5 External Asynchronous Timer/CounterO Digital External External General Timer/CounterO ADC ADC ADC ADC xiv CR2B Output Compare2 Register B ASSR Status Register GTCCR Timer/Counter Control Register Analog Input Ports AnalogtoDigital Converters ADC Peripheral Analog Comparator Pertinent Register Descriptions ADMUX ADCSRA ADCH and ADCL ADCSRB DIDRO Multiplexer Selection Register 140 Control and Status Register A 142 Data Register 143 Control and Status Register B 143 Digital Input Disable Register ACSR Analog Comparator Control and Status Register DIDR1 Input Disable Register Interrupt Processing Introduction Context ISR and Main Task Communication ATmega328P Interrupts in C Pertinent Register Descriptions EICRA EIMSK EIFR PCICR PCIFR PCMSK PCMSK PCMSKO TIMSKO TIFR TIMSK TIFR TIMSK TIFR2 Timer/Counter2 Interrupt Control Register A 154 Interrupt Mask Register 154 Interrupt Flag Register 155 Change Interrupt Control Register 155 Change Interrupt Flag Register 155 Change Mask Register Change Mask Register Change Mask Register Interrupt Mask Register 157 Interrupt Flag Register 157 Timer/Counterl Interrupt Mask Register 158 Timer/Counterl Interrupt Flag Register 159 Timer/Counter2 Interrupt Mask Register 159 Interrupt Flag Register 160

6 SPI SPI SPI Analog SPI XV SPCR SPSR UCSROA Control Register 160 Status Register 161 Control and Status Register A UCSROB Control and Status Register B TWCRTWI Control Register ADCSRA ADC Control and Status Register A 163 Comparator Control and Status Register ACSR EECR EEPROM Control Register 164 X0 Serial Communications Introduction InterIntegrated Circuit Serial Peripheral Interface Universal Asynchronous Receiver/Transmitter USART on ATmega328P Interruptbased Serial Port Management in C Pertinent Register Descriptions TWBR TWI Bit Rate Register TWCRTWI Control Register TWSRTWI Status Register TWDRTWI Data Register TWAR TWAMR TWI Slave Address Register 181 TWI Slave Address Mask Register SPCR SPI Control Register SPSR SPDR UDR UCSROA UCSROB UCSR0C UBRR0H and UBRR0L Status Register 183 Data Register 183 I/O Data Register 184 Control and Status Register A 184 Control and Status Register B 185 Control and Status Register C 186 Baud Rate Registers Assembly Language Introduction Arduino ToolChain Arduino Assembly Arduino Inline Assembly CInstruction Efficiency 205

7 EEPROM AVR EEPROM EEPROM 12 Nonvolatile Memory Introduction EEPROM via C on ATtnega328P Pertinent Register Descriptions EEARH High Address Register EEARL Low Address Register EEDR EEPROM EECR Data Register 214 Control Register 215 A Arduino 2009 Schematic 217 B ATmega328P Registers 221 B. l Register Summary 221 C ATmega328P Assembly Instructions 225 C. l Instruction Set Summary 225 C.2 Instruction Set Notation 232 C.2.1 SREG C.2.2 General Purpose Register Status Register 232 File 233 C.2.3 Miscellaneous 233 C. 2.4 Stack Pointer 234 D Example C/C++ Software Coding Guidelines 235 D. l Introduction 235 D. l.l Purpose 235 D.1.2 Philosophy 236 D.1.3 Format 236 D.2 General Recommendations 237 D.3 Naming Conventions 237 D.4 Layout 238 D.5 Statements 242 D.5.1 Types 242 D.5.2 Variables 242 D.5.3 Loops 243 D.5.4 Conditionals 244 D.5.5 Functions 244

8 CONTENTS xvii D.5.6 Miscellaneous 245 D.6 Comments 246 D.7 Files 247 Bibliography Author's Biography