The compiler transforms code while preserving meaning — but forget volatile and it changes the meaning too. See how assembly changes between -O0 and -O2 with objdump, and close out 12 episodes with the ‘conditions for embedded mastery.’
“RAM is full!” “A variable is changing on its own…” The answer is in the map file. This episode covers what .text/.data/.bss really are, how to read a linker script, how to stop stack overflows — and what the 512,000-line Claude Code leak teaches us about map file hygiene.
Stop having the CPU send bytes one at a time — let DMA handle everything. By DMA-ifying UART transmission, the CPU is freed to do real work. Episode 10 builds intuition for throughput, latency, and bus contention.
printf in ISR, missing volatile, heavy processing, forgotten flag clear — we deliberately trigger every classic embedded landmine and watch them fail. Applies to Arduino, ESP32, Renesas, PIC — every MCU with interrupts.
Why does polling fail when you need to ‘do something every 1ms’? Understand the vector table, NVIC, and context saving — then implement a 1ms periodic event with TIM2 interrupts.
How many CPU cycles does ‘wait 1 second’ actually consume? Learn to measure execution time in µs using DWT CYCCNT, and internalize the embedded engineer’s iron rule: ‘you can’t discuss it without measuring it.’