Summary

This post drills into the low-level startup code for an ARM-based embedded system, expanding on the earlier high-level sequence overview. The reader will learn concrete details like the vector table layout, reset handler responsibilities, .data/.bss initialization, and how the C runtime is invoked from assembly startup.

Key Takeaways

• Understand the purpose and layout of the vector table and how the reset vector transfers control
• Implement a reset handler that sets up the stack pointer, initializes .data and clears .bss, and jumps to main
• Write and verify linker scripts and memory maps to place vectors, code, and RAM data correctly
• Use startup assembly and minimal C runtime (crt0) patterns compatible with GCC/ARM toolchains
• Validate startup behavior with low-level debugging and simple sanity checks before enabling higher-level subsystems

Who Should Read This

Embedded firmware engineers and MCU developers with some ARM experience who need to implement, audit, or debug startup/boot code and linker scripts to ensure correct system bring-up.

Still RelevantIntermediate

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