Zephyr Course 2026 by iomico

Add a configurable heartbeat LED to the blinky app from the demo.

• Create `app.overlay` — add alias `app-led` pointing to your board's `led0`

• Add `Kconfig` file with;

• `int APP_HEARTBEAT_PERIOD_MS` (default `500`, range `100`–`2000`)

• In C: use `DT_ALIAS(app_led)` for the GPIO and `CONFIG_APP_HEARTBEAT_PERIOD_MS` for the sleep duration

• Verify: open `menuconfig`, change the period, rebuild — LED blink speed must change

• Push tag: `l4-task1`