Embedded Systems Architecture programming and design--Chapter 1 Summary

The embeded system is a sophisticated system consisting of several hardware and software componets,and its design may be serveral times more complex than that of a PC and the programs running on a PC.

The embeded system processor can be a general-purpose processor chosen from number of families of processors,microcontrollers,embedded processors and digital signal processors(DSPs).Alternatively, an application specific instruction processor(ASIP)may be designed for specific application on a VLSI chip.An ASSP may be additionally used for fast hardwired implementation of a certain part of a certain part of the embeded software.A sophisticated embedded system may use multiprocessor unit also.

Embedded system embedded (locates)a software image in the ROM. The image mostly consists of the following:(i)Boot up Program.(ii)Initialization data(iii)Strings for an initial screendisplay or system state.(iv)Programs for the multiple tasks that the system performs.(v)RTOS kernel.

 The embedded system needs a power source and controlled and optimized power-dissipation from the total energy requirement for given hardware and software.The charge pump provides a power-supply-less system in certain embedded system.

The embedded system needs clock and reset circuits. Use of clock manager is a recent innovation.

The embded system needs interfaces:IO ports,serial UART and other pots to accept inputs and to send outputs by interacting with the peripherals,display units,keypad or keyboard.

The embedded system may need bus controllers for networking its buses with other systems.

The embedded system needs timers and a watchdog timer for the system clock and for realtime program scheduling and control.

The embedded system needs an interrupt controlling unit.

The embedded system may need ADC for taking analog input from one or multiple sourcesIt needs DAC using PWM for sending analog putput to motors,speaker,sound systems,etc.

The embedded system may need an LED or LCD display units,keypad and keyboard,pulse dialer,modem,transmitter,multiplexers and demultiplexers.

Embedded software is usually made in the high-level languages C or C++ or JAva with certain features added,enabled or disabledfor programming .'C' and C++ also facilitates the incorporation assembly language codes.

The embedded system most often needs a real-time operating system for real-time programming and scheduling,device drivers,device management and multitasking.

There are a number of software tools needed in the development and design phase of an embedded system.

There are a large number of applications and products that employ embedded systems.

A VLSI chip can embed IPs for the specific applications ,besides the ASIP or a GPP core.A system-on-chip is the latest concept in embedded systems,for example, a mobile phone. A contact-less smart card is one such application.