@startuml
scale max 900*520
skinparam backgroundColor transparent
skinparam shadowing false
skinparam defaultFontName "DejaVu Sans Mono"
skinparam defaultFontSize 13
skinparam rectangleBorderColor #2b6f8e
skinparam rectangleBackgroundColor #edf6fa
skinparam ArrowColor #8295a0
top to bottom direction
title A1 CONTEXT — command producer, timer daemon and callbacks
rectangle "01 Application task\ncontroller · priority 2" as App
rectangle "02 Timer command queue\nlength 8 · copy command" as Queue
rectangle "03 Timer daemon task\npriority 3 · own stack" as Daemon
rectangle "04 Active timer lists\none-shot + auto-reload" as Lists
rectangle "05 Callback application code\nshort · non-blocking" as Callback
App --> Queue : start / reset / change / stop
Queue --> Daemon : receive command
Daemon --> Lists : update expiry
Lists --> Daemon : expiry at tick
Daemon --> Callback : direct call
@enduml