Beginning STM32: Developing with FreeRTOS, libopencm3, and GCC (Maker Innovations Series)

See how using FreeRTOS and libopencm3 instead of the Arduino software environment will help you develop multi-tasking applications that go beyond Arduino norms. This updated version includes expanded coverage of software setup for Windows 10 and 11, additional TM32 hardware capabilities, including clear explanations of "totem pole outputs" versus "open drain outputs," and a new section on project showcasing an interrupt-driven approach for processing USART data. Each chapter contains clear explanations of the STM32 hardware capabilities to help get you started with the device, including GPIO and several other ST Microelectronics peripherals like USB and CAN bus controller. You’ll learn how to download and set up the libopencm3 + FreeRTOS development environment, using GCC. With everything set up, you’ll leverage FreeRTOS to create tasks, queues, and mutexes. You’ll also learn to work with the I2C bus to add GPIO using the PCF8574 chip. And how to create PWM output for RC control using hardware timers. You'll be introduced to new concepts that are necessary to master the STM32, such as how to extend code with GCC overlays using an external Winbond ​W25Q32 flash chip. Your knowledge is tested at the end of each chapter with exercises. Upon completing this book, you’ll be ready to work with any of the devices in the STM32 family. Beginning STM32, Second Edition provides the professional, student, or hobbyist a way to learn about ARM without costing an arm!What You'll Learn * Initialize and use the libopencm3 drivers and handle interrupts * Use DMA to drive a SPI based OLED displaying an analog meter * Read PWM from an RC control using hardware timers * Understand STM32 capabilities, including USB controller, RTC, DMA, CAN bus, and more Who This Book Is ForExperienced embedded engineers, students, hobbyists and makers wishing to explore the ARM architecture, going beyond Arduino limits. Table of Contents About the Author Chapter 1: Introduction STM32F103C8T6 FreeRTOS libopencm3 No Arduino No IDE Development Framework Assumptions About You What You Need ST-Link V2 Programming Unit Breadboard DuPont (Jumper) Wires 0.1 uF Bypass Capacitors USB TTL Serial Adapter Power Supply Small Stuff Summary Chapter 2: Software Setup Directory Conventions Used Operating Software Book Software Cloning with a github Account Anonymous github Download libopencm3 FreeRTOS Kernel ARM Cross Compiler Build the Software ST-Link Tool Windows User Installs Linux Account and Password Update the WSL Starting Ubuntu Updating Ubuntu Install Dependencies Windows Install usbipd Windows Ubuntu Software for usbipd STM32 ST-LINK Utility Summary Chapter 3: Power Up and Blink Power +3.3V Regulator USB Power/+5V +3.3V Supply One Power Source Rule Ground Reset Showtime ST-Link V2 st-flash Utility Read STM32 Write Image Erase Flash Windows STM32 ST-LINK Utility Function Info Function Read Function Write Function Erase Summary Bibliography Chapter 4: GPIO Building miniblink Flashing miniblink miniblink.c Source Code GPIO API GPIO Configuration Input Ports Output Ports Push/Pull or Totem Pole Outputs Open-Drain Outputs GPIO_MODE_OUTPUT_*_MHZ Ducks in a Row GPIO Inputs Digital Output, Push/Pull Digital Output, Open Drain GPIO Characteristics Input Voltage Thresholds Output-Voltage Thresholds Programmed Delays The Problem with Programmed Delay Summary Chapter 5: FreeRTOS FreeRTOS Facilities Tasking Message Queues Semaphores and Mutexes Timers Event Groups The blinky2 Program Build and Test blinky2 Execution FreeRTOSConfig.h FreeRTOS Naming Convention FreeRTOS Macros Summary Chapter 6: USART USART/UART Peripheral Asynchronous Data USB Serial Adapters Hookup Project uart Project Project uart2 USART API Include Files Clocks Configuration DMA Interrupts Input/Output/Status Ducks in a Row FreeRTOS Tasks Queues Summary Chapter 7: USB Serial Blue Pill USB Issue Introduction to USB Pipes and Endpoints USB Serial Device Linux USB Serial Device macOS USB Serial Device Windows USB Serial Device USB GPIO Demo Source Code cdcacm_set_config() cdc_control_request() cdcacm_data_rx_cb() USB Task USB Receiving USB Sending USB Serial Demo Summary Bibliography Chapter 8: SPI Flash Introducing W25QXX Serial Peripheral Interface Bus Chip Select Wiring and Voltages SPI Circuit Hardware /NSS Control STM32 SPI Configuration SPI Clock Rate SPI Clock Modes Endianness and Word Length SPI I/O Read SR1 Waiting for Ready Read Manufacturer ID Writing Flash Flash Erase Reading Flash Demonstration Running the Demo Manufacturer ID Power Down Summary Bibliography Chapter 9: Code Overlays The Linker Challenge MEMORY Section Entry Sections PROVIDE Relocation Defining Overlays Overlay Code Overlay Stubs Overlay Manager VMA and Load Addresses Linker Symbols in Code Overlay Manager Function Overlay Stubs Demonstration Extracting Overlays Upload Overlays to W25Q32 Overlay Demo Continued Code Change Trap Summary Bibliography Chapter 10: Real-Time Clock (RTC) Demonstration Projects RTC Using One Interrupt RTC Configuration RTC Clock Source Prescaler Starting Counter Value RTC Flags Interrupt and Setup Interrupt Service Routine Servicing Interrupts Task Notification Mutexes Demonstration UART1 Connections Running the Demo rtc_alarm_isr() EXTI Controller Configuring EXT17 Summary Chapter 11: I2C The I2C Bus Master and Slave Start and Stop Data Bits I2C Address I2C Transactions PCF8574 GPIO Extender I2C Circuit The PCF8574 Line PCF8574 Configuration PCF8574 GPIO Drive Wave Shaping Demo Circuit EXTI Interrupt I2C Software Testing I2C Ready Start I2C I2C Write I2C Read I2C Restart Demo Program Demo Session Summary Chapter 12: OLED OLED Display Configuration Display Connections Display Features Demo Schematic AFIO Graphics The Pixmap Pixmap Writing The Meter Software meter_init() meter_set_value() meter_redraw() meter_update() Main Module oled_command() oled_data() oled_reset() oled_init() Demonstration Summary Chapter 13: OLED Using DMA Challenges Circuit DMA Operation DMA Execution DMA Request Signals SPI1_TX Request The Demonstration Initializing DMA Launching DMA OLED SPI/DMA Management Task DMA ISR Routine Restarting DMA Transfers Executing the Demo Further Challenges Summary Chapter 14: Analog-to-Digital Conversion STM32F103C8T6 Resources Demonstration Analog Inputs PA0 and PA1 ADC Peripheral Configuration ADC Prescaler ADC Modes Sample Time Readying the ADC Demonstration Run Reading ADC Computing Temperature Voltage Reference Analog Voltages Summary Bibliography Chapter 15: Clock Tree In the Beginning RC Oscillators Crystal Oscillators Oscillator Power Real-Time Clock Watchdog Clock System Clock (SYSCLK) SYSCLK and USB AHB Bus rcc_clock_setup_in_hse_8mhz_out_72mhz() APB1 Peripherals APB2 Peripherals Timers rcc_set_mco() HSI Demo HSE Demo PLL ÷ 2 Demo Summary Bibliography Chapter 16: PWM with Timer 2 PWM Signals Timer 2 PWM Loop Calculating Timer Prescale 30 Hz Cycle Servo Hookup Running the Demo PWM on PB3 Other Timers More PWM Channels Summary Bibliography Chapter 17: PWM Input with Timer 4 The Servo Signal Signal Voltage Demo Project GPIO Configuration Timer 4 Configuration task1 Loop ISR Routine Demonstration Run Session Output Timer Inputs Summary Chapter 18: CAN Bus The CAN Bus Differential Signals Dominant/Recessive Bus Arbitration Synchronization Message Format STM32 Limitation Demonstration Software Build UART Interface MCU Flashing Demo Bus Session Run CAN Messages Synchronicity Summary Bibliography Chapter 19: CAN Bus Software Initialization can_init() CAN Receive Filters CAN Receive Interrupts Application Receiving Processing the Message Sending CAN Messages Summary Chapter 20: UART with Interrupts Background Interrupt Service Routines (ISR) Demonstration Program Design Clock Initialization GPIO Initialization UART Initialization Interrupt Service Routine Function uart_getc() Task main_task() Function uart_putc() Task tx_task() Running the Demo Configuration Demonstration Data Loss Summary Bibliography Chapter 21: New Projects Project Creation Makefile Macro BINARY Macro SRCFILES Macro LDSCRIPT Macro DEPS Macro CLOBBER Included Makefiles Header Dependencies Compile Options Flashing 128k FreeRTOS rtos/opencm3.c rtos/heap_4.c Required Modules FreeRTOSConfig.h User Libraries Rookie Mistakes Summary Bibliography Chapter 22: Troubleshooting Gnu Debugger (GDB) GDB Server Remote GDB GDB Text User Interface Peripheral GPIO Trouble Alternate Function Fail Peripheral Fail ISR FreeRTOS Crash Stack Overflow Estimating Stack Size When a Debugger Doesn’t Help Push/Pull (Totem Pole) or Open Drain Peripheral Defects Resources libopencm3 FreeRTOS Task Priorities Scheduling Within libopencm3 Summary Appendix A: Answers to Exercises Chapter 4 Chapter 5 Chapter 6 Chapter 7 Chapter 8 Chapter 9 Chapter 10 Chapter 11 Chapter 12 Chapter 13 Chapter 14 Chapter 15 Chapter 16 Chapter 17 Chapter 19 Chapter 20 Chapter 21 Appendix B: STM32F103C8T6 GPIO Pins Index See how using FreeRTOS and libopencm3 instead of the Arduino software environment will help you develop multi-tasking applications that go beyond Arduino norms. This updated version includes expanded coverage of software setup for Windows 10 and 11, additional TM32 hardware capabilities, including clear explanations of "totem pole outputs" versus "open drain outputs," and a new section on project showcasing an interrupt-driven approach for processing USART data. Each chapter contains clear explanations of the STM32 hardware capabilities to help get you started with the device, including GPIO and several other ST Microelectronics peripherals like USB and CAN bus controller. You’ll learn how to download and set up the libopencm3 + FreeRTOS development environment, using GCC. With everything set up, you’ll leverage FreeRTOS to create tasks, queues, and mutexes. You’ll also learn to work with the I2C bus to add GPIO using the PCF8574 chip. And how to create PWM output for RC control using hardware timers. You'll be introduced to new concepts that are necessary to master the STM32, such as how to extend code with GCC overlays using an external Winbond ​W25Q32 flash chip. Your knowledge is tested at the end of each chapter with exercises. Upon completing this book, you’ll be ready to work with any of the devices in the STM32 family. Beginning STM32, Second Edition provides the professional, student, or hobbyist a way to learn about ARM without costing an arm! What You'll Learn Initialize and use the libopencm3 drivers and handle interrupts Use DMA to drive a SPI based OLED displaying an analog meter Read PWM from an RC control using hardware timers Understand STM32 capabilities, including USB controller, RTC, DMA, CAN bus, and more Who This Book Is For Experienced embedded engineers, students, hobbyists and makers wishing to explore the ARM architecture, going beyond Arduino limits.