Beginning STM32: Developing with FreeRTOS, libopencm3, and GCC

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