Types of Embedded Systems: Characteristics & Classifications

A system is an arrangement in which all of its units assemble and work together according to a set of rules. The word “embedded” refers to combination or synchronization. Thus, an embedded system refers to a system that performs a particular task in a given time by synchronizing software (microcontroller) and hardware (PCB) together.

Some popular embedded systems applications are mobile phones, micro ovens, dishwashers, washing machines, pacemakers, printers, etc. All these applications combine the action of both hardware and software to perform a particular task. The time constraint is optional, however. Before we dive deeper into the types of embedded systems, let’s look at their unique characteristics and understand how they differ from general computing systems.

Characteristics of Embedded Systems

Unlike general computer systems, embedded systems work only for a particular function in a time-bound manner. For instance, a washing machine can not multitask like a laptop. In this regard, here are some unique characteristics of an embedded system.

Sophisticated Functionality

The functionality of no two embedded system applications is bound to be the same. The functionality of a washing machine is different from that of a microwave. However, the functionality of a laptop and a desktop are almost the same.

Real-Time Operation

It doesn’t mean live operation. It means the software programs hardware to operate in a time-bound fashion. It could also have two modes: Hard and Soft. The former mode indicates the task has to be completed within the allotted time (ex: clock), but in the soft mode, the system could use additional time over the allotted time (ex: microwave).

Low Manufacturing Costs

As an embedded system design aims for any particular application, it involves less manufacturing cost as compared to a versatile general computing system. As a result, embedded systems also require less power to perform operations.

Processor and Memory

Depending on the type, processor and memory requirements may vary. For instance, small embedded systems would require less memory, but sophisticated systems demand more memory and run on multi-core processors.

Tight Design Constraints

There are many design constraints to consider around the cost, performance, size, and power of an embedded system to realize its absolute performance. These design factors are kept to a minimum to justify their simple function.

General Purpose Systems vs. Embedded Systems

In order to better realize the characteristics of an embedded system, let’s compare it with a general computing system.

	General Purpose Computer	Embedded System
Purpose	Multipurpose	Single function
Constraint	Low or no resource constraint	Size, power, cost, memory, realtime
Performance	Faster and better	Fixed runtime requirement
User Interface	Can have keyboard, display, mouse, touch screen	Integrated into the real world with buttons, sensors, Leads, LCDs, Bluetooth system

Types of Embedded Systems

All types of embedded systems can be classified into two basic categories and their following subcategories as follows.

Based on Performance and Functional Requirements

Real-Time Systems

Perform a task in real-time
Offer quick responses under critical situations.
Further divided into two types of embedded systems:

Soft real-time embedded system: no time-bound operation is required. For instance, in a microwave oven, there is no strict cooking time instruction. You can customize time delays as per your requirement.
Hard real-time embedded system: strictly time-bound operation is necessary for a successful output, ex: traffic light control.

Stand-Alone Systems

Process digital/analog input signals into digital output
Less complex
Independent of any system
Ex: doorbell, calculator, MP3 player

Network Systems

Operate through a network interface
Communication to network happens through LAN, WAN, or other protocols
May be wired or wireless
Ex: ATM machines, weather monitoring systems

Mobile Systems

Small, portable and easy-to-carry
Work on restricted memory space
Constantly evolving to get into a miniature model
Ex: mobile phones, digital camera

Based on the Performance of the Microcontroller

Small Scale Systems

Entry-level embedded system with no design complexity involves
Work with 8-bit (8051) or 16-bit (80196) microcontrollers
Most of these systems are battery operated
Hardware and software complexity is very low due to the small size of microcontrollers
Easy to program using assembly language or C-programing language
Requires small memory as it deals with a small amount of data
Ex: robotic arm controller, electronic toys, automatic coffee vending machines, thermometer.

Medium Scale Systems

System is designed using 16-bit or 32-bit microcontrollers
Offers better speed than small scale Embedded system
Hardware and software complexity is present
Run through Microcontrollers and digital signal processors
Requires comparatively more memory power than small scale ones
Along with microcontrollers, you need application-specific operating systems
Ex: Routers, ATMs, music systems, pagers

Sophisticated Systems

Make use of 32-bit or 64-bit microcontroller and multi-core processors
Requires very high memory power
Power consumption is the highest among rest types of embedded systems
Hardware and software complexities are enormous
Speed is a major concern
Some applications, like satellite systems, also involve real-time operating system (RTOS)
Ex: mobile systems, washing machines, digital watches, LAN cards, multimedia systems

To ensure efficient board development with embedded systems, you need accurate component footprint data, CAD models, and information about microcontrollers to be used in the application.

Working with Ultra Librarian sets up your team for success to ensure streamlined and error-free design, production, and sourcing. Register today for free.