The course of true love never did run smooth

An electronic device that includes a programmable computer, but is not itself intended to be a general-purpose computer. It is not your desktop PC or portable PC. Some examples are Fax machines, Digital cameras, Mobile phones etc.

Millions of desktop PCs are manufactured every year; however, billions of embedded computer systems are also manufactured every year. For example, top of the range BMW cars contain over 150 dedicated embedded systems.

Following are the major characteristics of embedded systems,

• Dedicated to specific tasks
• Real-time constraints
• Cost sensitive
• Power sensitive
• Short design times
• Harsh operating environments
• Fail-safe operations

Following are the major challenges faced while designing embedded system,

• What is the optimum balance between hardware and software?
  • How much “hardware” do we need?
  • How much “software” do we need?
• How do we meet operational deadlines?
• How do we minimise power consumption?
• How do we design for upgradeability?
• How do we convince people that the system works properly?

Following are the steps involved in a typical design procedure for the embedded systems

• Capture and analyze the functional and non-functional requirements
• Develop a precise specification of the system functions
• Develop the overall system architecture
• Partition into “hardware” and “software” components
• Implement the hardware and software components. Reuse existing components where appropriate
• Integrate the components into a working system. Iterate the design process until the required working system has been produced

Embedded System is often used interchangeably with Real-time System, due to the real-time constraints involved in almost all the embedded systems. Real-time Embedded Systems are typically monitoring and/or control systems. The external environment (system or machine) is often termed the Controlled System. The Real-time Embedded System (including its hardware/OS) is known as the Controlling System. The real-time embedded systems include following additional characteristics.

• Concurrency - Simultaneous Processing
• Timeliness - Respond to events in short time
• Dependability - Failure of RTES maybe expensive/dangerous
• Interface with non-standard hardware – Due to dedicated hardware devices for performance gain

Real-time Embedded Systems (RTES) typically performs three categories of activity. Data acquisition – gathers data about the controlled system. Control system – analyse the data and determine the action the system should take. Human-Computer Interaction - receives commands and provides feedback to user if there is one.