Design

• Start general
• Add more detail as you understand the problem
• Let it unfold

Design Objectives

• Small clearly focused components
• Think of it as a bucket brigade
• Synchronize action with semphores
• Protect changes to data with semphores, mailboxes, queues
• Watch out for priority inversion. Use Mutexes where necessary.

Design Patterns

• Worker tasks for interrupt handling
  • Do the interrupt handling work in a task not in the interrupt routine
  • Have a task waiting on a semphore
  • Have the interrupt routine signal the semphore

Top Down Diagram

Possible Design