Embedded Systems Flashcards
Define Embedded Systems
Embedded system can be defined as the combination of hardware, and software, as well as additional mechanical or other components designed to carry out a dedicated function. It usually in several cases a part of a larger system such as antilock braking system in a car.
These systems are purpose-built for specific tasks and are often dedicated to performing a single function or a set of closely related functions.
5 Examples of Embedded systems
- Office Automation which includes fax machines, photocopiers, printers, monitors as well as scanners.
- Medical Devices such as infusion pumps, dialysis machine, cardiac monitor and a prosthetic devices.
- Automotive such as ignition system, engine control as well as brake systems.
- Consumer electronics such as cell phones, global positioning systems, cameras, toy games, automobiles, refrigerators, set top boxes, ebooks and MP3.
- Industrial control system such as robotics, control system for manufacturing sensors, missiles, space stations as well as shuttles
- Networking which includes router, Hubs, gateways and electronic instruments
10 Characteristics of Embedded Systems
- A simple embedded system with simple functionality may be controlled by special purpose program or set of programs with no other software. Notwithstanding complex embedded systems do require operating systems.
- Realtime operation: In many embedded systems, the correctness of a computation depends on the time at which it is delivered. Often real time constraints are dictated, by external I/O and control stability required.
- All embedded systems are task-specific.
- They require no or little user interface.
- Embedded systems usually require connected devices to attach input /output devices.
- Embedded systems are designed by microcontrollers or microprocessors.
- Embedded system hardware is used for security and performance while the software for features and flexibility.
- Embedded systems are small in size, consume less power, and are not too costly.
- They cannot be modified or upgraded by the users.
- Several embedded systems are designed to react to outside stimuli and react as a result.
- Embedded systems are constrained in terms of CPU, speed, memory, and connectivity.
CATEGORIES OF EMBEDDED SYSTEM
(a) Small scale Embedded System
(b) Medium Scale Embedded System.
(c) Sophisticated Embedded system.
Explain Small Scale Embedded System
They refer to the categories of embedded systems designed with a single 8 or 16 bits microcontroller. They can be activated with battery. They require the programming tools such as editor, cross assemble and assembler (IDE) for development.
Medium Scale Embedded System
These categories of embedded system are designed using 16 or 32 bits of microcontroller. Medium scale embedded systems gives both software and hardware complexities. To develop a medium scale embedded system, we use C, C++, Java as well as code engineering tools.
Sophisticated Embedded Systems
This category of embedded systems possess several hardware and software complexities. You may need a configuration process, ASIS as well as PLA. To develop sophisticated embedded systems, a combination of both hardware and software and other components which must be added to the system are required.
COMPONENTS OF EMBEDDED SYSTEM
Software,
Operating System,
Hardware
Embedded controller
An embedded controller is a control system that possess the ability to handle complex data as well as perform independent control functions in embedded systems.
Embedded processor
Embedded processor is responsible for controlling the core work of the embedded system operations.
Embedded Processor Features
- Robust interrupt handling ability,
- Scalable microprocessor architecture,
- Memory protection, low power consumption.
- Real-time memory multitasking ability.
- Embedded processors come in four ways
Embedded Processor Main Features (4)
(a) Embedded Microcontroller Unit: This is a complete computer system integrated into a chip, where the system’s significant signal control tasks are done.
Embedded system microcontrollers are timers/counters, input/output, communication bus, watchdog timers, RAM, serial interface, D/A, ROM/EPROM, A/D as well as other peripheral devices.
(b) Embedded Digital Signals Processor unit: This is the system instruction algorithm and structure features of a special design earmarked for signal processing processors. It has high implementation instruction execution speed as well as high efficiency.
It has been extensively used in various application areas such as spectrum analysis, digital filtering, image processing, FFT as well as other instruments.
(c) Embedded Microprocessor Unit: This is a general-purpose computer from CPU changed, but different from the general-purpose computer CPU in the sense that embedded systems are application specific.
The embedded microprocessor will only keep the hardware function that is specific to that application and eliminate the other redundant embedded system parts. Microprocessor is noted to be highly reliable, consume low power, light weight, low cost as well as small in size.
(d) Embedded System on Chip (SOC): Embedded system is the leading, wide ranging incorporated devices, breaking the limitations between hardware and the software is considered as the main feature of embedded system on chip. Hardware description language inside silicon chip and VDHL enables it to become a complex system. SOC has gain, in that a significant number of the system’s components are thereby enabling the entire system to be greatly simplified, energy consumption decrease , small size, as well as production and design efficiency.
Embedded Peripheral Hardware Devices (5)
- Serial Communication Interfaces (SCI) like RS-232, RS-422, RS-485, etc.
- Synchronous Serial Communication Interface like I2C, SPI, SSC, and ESSI.
- Universal Serial Bus (USB)
- Multi Media Cards (SD Cards, Compact Flash, etc.)
- Networks like Ethernet, LonWorks, etc.
Embedded Operating System
Embedded Operating System: This is the operating system used in embedded systems. It handles tasks such as resource allocation in both hardware and software, concurrency, coordination as well as scheduling in the embedded system.
Examples of embedded operating systems are Linux, VxWorks, QNX as well as windows CE etc.
Embedded Application Software:
This is the top layer of the embedded system software, which is responsible for user communication with the system, as well as specifying the major task of embedded devices and their uses.
