Explanation: The embedded system consist of different components embedded into it as follows: 1) Embedded Processor 2) Power supply , reset and Oscillator circuits 3) System timers 4) Serial communication port 5) Parallel ports 6) Interrupt controller 7) Output and Input Interfacing and driver circuits 8) System application specific circuits 9) Program and Data memory
Processor: The processor is the heart of embedded system. The selection of processor is based on the following consideration 1. Instruction set 2. Maximum bits of operation on single arithmetic and logical operation 3. Speed 4. Algorithms processing and capability 5. Types of processor( microprocessor, microcontroller, digital signal processor, application specific processor, general purpose processor)
Power supply, Reset, Oscillator circuit and system timers:
Power source: Internal power supply is must. Es require from power up to power down to start time task. Also it can run continuously that is stay “On’ system consumes total power hence efficient real time programming by using proper ‘wait’ and ‘stop’ instruction or disable some unit which are not in use can save or limit power consumption.
Clock / oscillator Circuits The clock ckt is used for CPU, system timers, and CPU machine cycles clock controls the time for executing an instruction. Clock oscillator may be internal or external .It should be highly stable
Real time clock(RTC): It require to maintain scheduling various tasks and for real time programming RTC also use for driving timers, counters needs in the system.
Resets Ckts and power on reset: Reset process starts executing various instruction from the starting address. The address is set by the processor in the program counter. The reset step reset and runs the program in the following way 1. System program that execute from beginning 2. System boot up program 3. System initialization program
Serial and Parallel communication ports: Serial communication port and parallel communication ports are used to interface serial and parallel devices with the system and communicate between processor and devices.
Interrupt controller: It is used to receive interrupt from various sources and resolve the priority and provides the service to that interrupts.
Input and output interfacing and driver circuits: Characteristics of input or output devices may be different from the processor like voltage and current requirement to drive that specific device, hence driver circuits are needed to drive input or output devices.
Program and Data memory: The most microcontroller have inbuilt separate memory to store data and program. Following are types of memories used in embedded system.