Introduction to Embedded Systems
The Combination of Software and Hardware in which the software controls the entire hardware for a dedicated application.
Components of an Embedded Systems
* Power Supply and Reset circuit
* Watch Dog Timer or WDT
RAM Which stores the data (data Memory)
ROM Which stores the Program (Program Memory)
* Interrupt controllers
* IO Ports
* UART for Serial communication
* Parallel ports
Classification of Embedded Systems
Small Scale Embedded Systems
* Uses 8 or 16 bit microcontrollers
* Software and harware complexity is very less
* uses C as a programming language
* The codes are cross compiled and stored in the system memory.
* They sometimes may be battery operated.
Example processors : Intel 8051, Microchip PIC16f8X, Motorola 68HC05,08
Medium Scale Embedded Systems
* Uses 16 or 32 bit controllers or sometime uses DSPs(Digital Signal Processors) or RISC (Reduced Instruction Set Processors)
* They have great complexity.
* They use a Real Time Operating Systems (RTOS), SImulators, Debuggers, emulators, and IDE to develop all these functionalities.
Example: Intel 8051, 80251,80196 Motorola 68HCX11,12
Large Scale Embedded Systems
* They use 32 bit processors.
* They use CPLDs or FPGAs or ASICs
* They are System on Chip Controllers
* They go from initial design like co design and co analysis and co verification
* The Processing speeds are very high in these systems.
* They sometime may be proprietary systems in which the development tools may not be available at all.
Example: ARM7, IBM Power PC