1. THE PROCESS OF EMBEDDED SYSTEM DEVELOPMENT
UNIT-II
THE PROCESS OF EMBEDDED SYSTEM DEVELOPMENT

2. OUTLINE The Development Process The Waterfall Model
Requirement Engineering
Design
Implementation
Integration and Testing
Packaging
Configuration Management
Managing Embedded System Development
Embedded System Fiascos

3. The Development Process
Raw Material
Finished Product
H/W Development
Problem Definition
Finished Product
S/W Development

4. The Waterfall Model

5. Requirement Engineering
ES development projects is divided into two categories:
Product development
Based on Marketing department’s inputs
Turnkey project execution
Based on requirement given by client
Problem definition will be very vague such as – develop a handheld data terminal for used by field personnel or develop a process control system for use in pharmaceutical company.
To convert problem definition into a detailed requirement document.

6. Requirement Engineering
Requirement Analysis Phase:
The inputs to the system
The outputs of the system
The processing to be done by the system along with timing restrictions, if any
Input supply voltage
The communication interfaces to be provided
The size of the embedded system
Operating environment
Standards to be followed,. Every industry segment specific standards. These statutory standards need to be obtains from client.

7. Requirement Engineering
Once these requirements are obtained, they need to be documented and a document called requirements specifications has to be prepared.
It can be divided into two parts-
Functional requirements
Non-functional requirements
Reliability- Mean Time Between Failures (MTBF)
Delivery time
Implementation requirements
Standards
Safety requirements
Security
Requirement validation phase is to ensure that the requirement specifications document captures all the requirements of the user and also to ensure that the required embedded system can be designed and developed

8. Design The design goals are- Design tradeoffs
To meet all the functional and performance requirement.
To reduce the size and cost of the system to the extent possible.
To reduce the power consumption of the system.
To reduce the development time and effort.
To reduce the maintenance effort and time.
To increase the reliability.
Design tradeoffs
Which processor to use?
Is an FPGA required?
Is it necessary to embedded/real time OS on the target system?
The design process can be divide into-
Hardware-software partitioning or co-design.
Hardware design
Software design

9. Co-design Example – CRC algorithm
Decision on implementation in software or hardware needs to be taken keeping in view the following issues-
Speed of execution
Flexibility for making changes
Size
Power consumption
Memory
Cost
Intel’s is an integer-only processor – Intel’s is an floating point processor.
Graphics accelerator
PLDs, FPGAs and SoC- reconfigurable hardware.

10. Hardware Design The hardware design involves-
Selection of the processor
Calculation of memory requirements and types of memory.
Identification of input devices.
Identification of output devices.
Identification of test points - JTAG debugging - design board keeping in view of debug pins.
Identification of supply voltages and current requirements for designing the power supply unit.
Start with block diagram and then convert into circuit with necessary interconnections.
Hardware design not done in isolation interaction with software engineers is required.

11. Hardware Design Selection of the processor
Micro-controller
Microprocessor
Digital Signal Processor
If a micro-controller is not sufficient for the application, the selection of the processor is based on following criteria-
Performance requirements – MIPS and EEMBC
Cost of the processor
Development tools – cross compiler & debugger
Special requirements
Support for RTOS
Technical support from the vendor
Availability of people with the expertise on specific processor.

12. Software Design Software design involves –
Working out the details of processing to be done in ES.
Decomposition of the processing into different tasks.
Calculation of the processing time and resources required for each task.
Deciding on the use of embedded operating system.
Studying the need for support for communication protocols stack.
Study the need for embedding the HTTP server software.
Study the need for field Upgradation of the software.
Selection of an Operating System-
Optimized kernel for the chosen processor.
Support for languages.
Support for POSIX function calls.
Footprint
Software components
Source code/object code
Licensing fee

13. Implementation Hardware implementation involves –
Developing the circuit schematics.
Obtaining the PCBs.
Procuring the components.
Assembling the components and testing the individual modules on the populated PCB.
Testing the complete hardware.
Software implementation involves converting the design into code.
Implementation of the software is generally done on a host system and then executable code is transferred to the target hardware.

14. Integration and Testing
What is testing?
Testing is the process to prove that the system works correctly.
Testing is the process to prove that the software does not work correctly.
Testing is the process to reduce the risk associated with the residual defects.
Types of Testing
Black-box testing
White-box testing
Performance testing
Gorilla testing
Field trial
Acceptance testing
Regression testing

15. Integration and Testing
Testing the embedded system involves two steps-
Testing on the Host System
Testing on the Target System
To validate the software
Tools such as ROM emulator, code simulator, IN-circuit emulator, etc
Testing the hardware functionality partially
Performance characteristics cannot be tested on the host system
Functional requirements
Performance requirements
Environmental requirements
Simulation Engineering
Environmental Testing

16. Configuration Management
System requirements specifications
Project plan
H/W design document
S/W design document
Circuit diagrams
Source code
Acceptance test procedure
Test plans
User manual
Change Request
Impact on Budget & Time
Impact on Functional & Performance Requirements
Change Request Analysis (Impact Analysis)
Changed Work Products
Release of Engineering Change Note
Changed Implementation
Change Release
System Testing

17. Managing Embedded System Development Projects
Project Proposal Preparation
Project Planning
Providing the Development Infrastructure
Co-Design and Co-Verification
Risk Management
Quality Management