Waterfall Development Approach

The traditional process for developing embedded controllers is still very closely related to the "waterfall" development model which involves the following set of activities performed more-or-less sequentially:

• advanced R&D design new features
• high level requirements
• high level design
• detailed requirements
• functional tests
• detailed design documents
• coding of architecture
• coding of features
• unit testing of features
• incremental integration and regression testing
• functional, HIL testing
• system testing

Issues

• Requirements and integration errors are discovered late in the process
• Remediation of these errors requires repeating all interim steps
• Coding and debugging is time intensive, costly and difficult
• The total elapsed time for the most simple controls is many months
• No requirements changes can be made or advanced algorithms introduced without jeopardizing the entire project

The better solution is agile, model-based design...