Your board is silent. Stop guessing why.

This field guide teaches a repeatable, evidence-first workflow for taking a Cortex-M system from reset to observable, working firmware. It examines each layer directly—from the reset vector and linker script to memory initialization, clocks, faults, GPIO, and the first UART output.

What you will learn

  • Trace execution from the vector table through Reset_Handler to main().
  • Understand how Flash, SRAM, startup code, and the linker script work together.
  • Verify that .data is copied and .bss is cleared correctly.
  • Configure clocks safely using status checks and timeouts.
  • Use GPIO and MCO as physical proof signals.
  • Capture and decode fault evidence.
  • Bring up UART from raw registers and verify baud timing.
  • Retarget printf and build dependable diagnostic logging.

What you receive

  • A visual, beginner-friendly firmware bring-up field guide.
  • A printable workbook with proof-driven exercises.
  • Complete reference source code.
  • GDB and Renode debugging scripts.
  • Practical bring-up and troubleshooting checklists.
  • An editable copy of the lab workbook.

Platform and prerequisites

The examples use an STM32F4-style Cortex-M4 environment, but the workflow applies broadly to ARM Cortex-M microcontrollers. Basic familiarity with C is helpful; prior experience writing startup code, linker scripts, or assembly is not required.