Mr. Integral

THE EMBEDDED NOTEBOOK

Every block of the chip, one unit at a time.

Pick a part of the microcontroller to learn how it works. All 15 units are ready to explore, from basic circuits to reliable firmware.

90 lessons available · 15 of 15 units ready · every concept independent of any chip vendor

∫ MR-INTEGRAL · 15 UNITS · 90 LESSONS016 lessonsPinssignals and circuits036 lessonsCPU coreand memory026 lessonsRegisters096 lessonsInterruptcontroller136 lessonsSchedulertasks and deadlines046 lessonsFlash imagebuilt by the toolchain156 lessonsSecure bootupdates and keys056 lessonsBoot ROMand reset066 lessonsDebug portprobe, trace146 lessonsPowersleep, brown-out126 lessonsDMA076 lessonsGPIOpins in and out086 lessonsClocksand timers106 lessonsUART · SPI · I²Cserial links116 lessonsADC · DACanalog
∫ MR-INTEGRAL · 15 UNITS01Pins · signals and circuits036 lessonsCPU coreand memory026 lessonsRegistersC close to the metal096 lessonsInterruptcontroller136 lessonsSchedulertasks and deadlines046 lessonsFlash imagebuilt by the toolchain156 lessonsSecure bootupdates and keys056 lessonsBoot ROMand reset066 lessonsDebug portprobe, trace146 lessonsPowersleep, brown-out126 lessonsDMA076 lessonsGPIOpins in and out086 lessonsClocksand timers106 lessonsUART · SPI · I²Cserial links116 lessonsADC · DACanalog

Ready now

UNIT 01 · 6 LESSONS

Signals and Circuits

Where the software meets the wire.

UNIT 02 · 6 LESSONS

Programming Close to Hardware

Where the C compiler meets the silicon.

UNIT 03 · 6 LESSONS

Processors and Memory

What the chip does with every address.

UNIT 04 · 6 LESSONS

The Build Toolchain

From text files to the bytes in flash.

UNIT 05 · 6 LESSONS

Startup and Boot

Everything that runs before main().

UNIT 06 · 6 LESSONS

Debugging and Measurement

See what the chip is really doing, without changing it.

UNIT 07 · 6 LESSONS

Digital Input and Output

Pins that read, drive and survive the real world.

UNIT 08 · 6 LESSONS

Clocks and Timers

Every microsecond, counted by hardware.

UNIT 09 · 6 LESSONS

Interrupts and Events

React to the world the moment it changes.

UNIT 10 · 6 LESSONS

Serial Communication

Move bytes between chips, one bit at a time.

UNIT 11 · 6 LESSONS

Analog Signals and Conversion

Turn voltages into numbers, and numbers back into voltages.

UNIT 12 · 6 LESSONS

Data Transfer and Buffering

Let hardware move the data while the CPU does the thinking.

UNIT 13 · 6 LESSONS

Concurrency and Real-Time Design

Do many things at once, and prove each one is on time.

UNIT 14 · 6 LESSONS

Power and Reliability

Run for years on a battery, and recover when things go wrong.

UNIT 15 · 6 LESSONS

Firmware Updates and Security

Ship new firmware without bricking the device or trusting strangers.

All 90 lessons as a list

Foundations

Signals and Circuits

  1. Voltage, Current, and Ground
  2. Digital Signals and Logic Levels
  3. Resistors, Pull-Ups, and Pull-Downs
  4. Capacitors and Decoupling
  5. Switches, LEDs, and Interface Circuits
  6. Reading Schematics and Datasheets

Programming Close to Hardware

  1. Binary, Hexadecimal, and Bit Operations
  2. Integer Types, Signedness, and Overflow
  3. Pointers, Arrays, and Addresses
  4. Structures, Alignment, and Data Layout
  5. Memory-Mapped Registers and Volatile
  6. Undefined Behavior and Safe Register Access

Processors and Memory

  1. What Is Inside a Microcontroller?
  2. Instructions, Registers, and the CPU
  3. Buses and Address Spaces
  4. Flash, RAM, and Nonvolatile Memory
  5. The Stack, the Heap, and Static Storage
  6. Clocks, Reset, and Execution

Building and Running Firmware

The Build Toolchain

  1. From Source Code to Machine Code
  2. Compiling, Assembling, and Linking
  3. Object Files, Symbols, and Libraries
  4. Linker Scripts and Memory Sections
  5. Reading a Map File and Disassembly
  6. Build Configurations and Reproducible Builds

Startup and Boot

  1. What Happens at Reset?
  2. Boot Sources and Address Mapping
  3. Entry Points and Exception Tables
  4. Initializing the Stack and Runtime Memory
  5. From Startup Code to the Application
  6. Writing a Minimal Startup Sequence

Debugging and Measurement

  1. Programming and Connecting to a Target
  2. Breakpoints, Stepping, and Watchpoints
  3. Inspecting Registers, Memory, and the Stack
  4. Finding Crashes and Faults
  5. Using a Logic Analyzer and Oscilloscope
  6. Measuring Timing Without Disturbing It

Interacting with Hardware

Digital Input and Output

  1. Pin Modes and Alternate Functions
  2. Push-Pull and Open-Drain Outputs
  3. Reading Inputs and Handling Floating Pins
  4. Debouncing Buttons and Switches
  5. Driving Loads and Protecting Pins
  6. Designing a Nonblocking Input-Output Loop

Clocks and Timers

  1. Clock Sources, Dividers, and Clock Trees
  2. Counters, Prescalers, and Timer Periods
  3. Measuring Elapsed Time and Handling Wraparound
  4. Periodic Events and Output Compare
  5. Measuring Pulses with Input Capture
  6. Pulse-Width Modulation and Duty Cycle

Interrupts and Events

  1. Polling, Interrupts, and Events
  2. Interrupt Requests and Handler Execution
  3. Latency, Priorities, and Nesting
  4. Acknowledging and Clearing Interrupt Flags
  5. Sharing Data with Interrupt Handlers
  6. Deferring Work and Keeping Handlers Short

Moving and Processing Data

Serial Communication

  1. Serial Data, Framing, and Synchronization
  2. UART and Asynchronous Serial Communication
  3. SPI and Synchronous Serial Communication
  4. I²C and Two-Wire Addressed Communication
  5. Differential and Multinode Networks
  6. Packet Design, Checksums, and Timeouts

Analog Signals and Conversion

  1. Sampling, Aliasing, and Bandwidth
  2. Resolution, Quantization, and Accuracy
  3. References, Input Impedance, and Acquisition Time
  4. Triggered Sampling and Conversion Sequences
  5. Digital Filtering and Sensor Calibration
  6. Analog Outputs and PWM Filtering

Data Transfer and Buffering

  1. Moving Data Without the CPU
  2. Transfer Sources, Destinations, and Requests
  3. Transfer Widths, Alignment, and Address Increment
  4. Circular Buffers and Producer-Consumer Flow
  5. Double Buffering and Continuous Streams
  6. Buffer Ownership, Overruns, and Cache Coherency

Building Reliable Systems

Concurrency and Real-Time Design

  1. State Machines and Event-Driven Design
  2. Cooperative Scheduling and Superloops
  3. Tasks, Context Switching, and Scheduling
  4. Queues, Semaphores, and Mutexes
  5. Race Conditions, Deadlocks, and Priority Inversion
  6. Deadlines, Execution Budgets, and Timing Analysis

Power and Reliability

  1. Sleep States and Wake-Up Sources
  2. Measuring Power and Energy
  3. Watchdogs and Recovery Strategies
  4. Brownouts, Reset Causes, and Safe States
  5. Persistent Settings and Power-Loss Safety
  6. Testing Firmware and Handling Failures

Firmware Updates and Security

  1. Application Images and Bootloaders
  2. Image Integrity and Authenticity
  3. Safe Updates, Rollback, and Recovery
  4. Secure Boot and the Root of Trust
  5. Protecting Keys, Debug Ports, and Device Identity
  6. Versioning, Diagnostics, and Field Maintenance