An embedded system is an applied computer system which has a specific application, as distinguished from other types of computer systems such as personal computers (PCs) or supercomputers.
But, the definition of embedded system is fluid and cannot be pinned down to one sentence. In recent years, the field has outgrown many of its traditional descriptions. Following are some of the commonly used definitions:
- Embedded systems are devices with limited hardware or software functionality but boards like the Raspberry Pi implement a functionality rich embedded system.
- It can be a device with higher quality and reliability requirements as compared to a PC, such as in healthcare, automobile. However, there are also embedded devices, such as TVs, games, and cell phones, in which a malfunction is an inconvenience but not usually a life-threatening situation.
- An embedded system can be a device performing specific tasks yet latest devices such as smartwatches perform more than one function simultaneously.
What is the difference between a microcontroller and a microprocessor in embedded systems?
A microcontroller is a compact chip with a CPU, memory, and peripherals integrated, designed to perform specific control tasks in embedded systems. A microprocessor, on the other hand, is a powerful CPU that requires external components and is used for general-purpose computing like in PCs.
High Level Model
The high level model is one of the architectural representation used to describe embedded systems at a higher level. It contains the following 3 levels, in the same order - i.e. the hardware layer at the lowest and software layer at the top.
1. Hardware
- Microcontroller/Microprocessor
- Memory (RAM, ROM, Flash)
- I/O Devices (sensors, actuators)
- Timers, ADC/DAC, Communication Interfaces
2. Firmware
- Device Drivers
- Operating System / RTOS (if used)
- Bootloader
- Handles low-level tasks like resource allocation, interrupt handling, task scheduling.
3. Software
- Your custom code that defines the application logic (e.g., turn on fan if temp > 30°C).
- Written in C/C++ or sometimes Python (e.g., MicroPython).
- Directs how the system reacts to inputs, controls outputs, manages state, etc.
Characteristics of an Embedded System
- Performs specific task: Embedded systems perform some specific function or tasks.
- Low Cost: The price of an embedded system is not so expensive.
- Time Specific: It performs the tasks within a certain time frame.
- Low Power: Embedded Systems don’t require much power to operate.
- High Efficiency: The efficiency level of embedded systems is so high.
- Less Human intervention: Embedded systems require less to no human intervention.
- Highly Stable: Embedded systems do not change frequently mostly fixed maintaining stability.
- High Reliability: Embedded systems are reliable they perform tasks consistently well.
- Use microprocessors or microcontrollers: Embedded systems use microprocessors or microcontrollers to design and use limited memory.
- Manufacturable: The majority of embedded systems are compact and affordable to manufacture. They are based on the size and low complexity of the hardware.
Applications of Embedded Systems
Embedded systems are used across various domains to perform specific, dedicated tasks efficiently.
1. Automotive
| Embedded Device | Purpose |
|---|---|
| Ignition System | Starts the engine |
| Engine Control Unit (ECU) | Manages fuel injection, timing, etc. |
| Antilock Braking System (ABS) | Prevents wheel lock during braking |
2. Consumer Electronics
| Embedded Device | Example Use |
|---|---|
| Digital/Analog Televisions | Display and signal processing |
| Set-Top Boxes (DVDs, VCRs, Cable Boxes) | Media decoding and user interface |
| Personal Data Assistants (PDAs) | Handheld computing |
| Kitchen Appliances | Smart fridges, toasters, microwave ovens |
| Toys/Games | Interactive toys, gaming consoles |
| Phones, Pagers | Communication and signal control |
| Digital Cameras | Image capture, processing, storage |
| GPS Devices | Location tracking and navigation |
3. Industrial Control
| Embedded Device | Application |
|---|---|
| Robotics | Assembly lines, automation |
| Control Systems | Temperature, motion, pressure regulation |
4. Medical
| Embedded Device | Function |
|---|---|
| Infusion Pumps | Precise medication delivery |
| Dialysis Machines | Blood purification |
| Prosthetic Devices | Motor-controlled limb movement |
| Cardiac Monitors | Heart rate monitoring |
5. Networking
| Embedded Device | Function |
|---|---|
| Routers | Internet traffic management |
| Hubs | Network signal distribution |
| Gateways | Protocol translation, security |
6. Office Automation
| Embedded Device | Example Use |
|---|---|
| Fax Machines | Sending/receiving documents via telephone |
| Photocopiers | Document scanning and printing |
| Printers | Image/text printing |
| Monitors | Visual display interface |
| Scanners | Digitizing paper documents |