Things are getting smaller and smaller. But the services provided by this small devices aren’t small. They are having high capabilities of doing different tasks. The invention of IC has made this possible reduction of size of devices. But the use of different ICs made it difficult to reduce the size below a particular extend. This has been made possible by the introduction of a new method of construction called System on Chip. As the name indicates the whole system will be on the entire chip. It is capable to work individually without any additional device attached to it .

Structure of System on Chip
The main part of the SoC will be a microcontroller or a processor. This will be the unit which controls all the activities of that entire chip or device. The microcontroller will be provided with memory- which includes RAM and ROM. Size of RAM and ROM vary based on the controller used. RAM is used for temporary data storage. But ROM is used for permanent data storage. ROM contains information required for the basic working of the device. But the data present in RAM will be lost when power is lost. For flexibility now ROM cells used are of flash types. The advantage of such cells is that they can be programmed more than once.

There will be some registers for storing the results of some calculations performed by the controller or processor. The size of the registers varies from 4 bits to 16 bit etc. Higher the capability higher will be the data handling capacity. Also some registers for storing the device status like carry, parity etc will also be provided. The data present in such registers determine the present state of the entire system.
The speed of operation of these devices is controlled by some external circuits called the oscillators. As the oscillating frequency increases the speed of operation also increases. But there will be a maximum speed possible for a controller. Beyond that frequency the controller will not work. There will be an internal oscillator or clock inside the crystal. But the speed of that crystal will be small. So in order to increase the speed of operation external crystals are used. As the speed increases the number of instructions executed per second increases.
Sometime there will be essential for connecting external counters and timers for generating interrupts or for counting purposes. Such provisions will also be available in the chip.

External interfaces or data communication between the chip and the surrounding is essential for data processing and other operations. This can be made through the ports provided on the chip. There will be provision for interfacing USB, Ethernet, USART, SPI etc. This will make the system powerful for data processing and data related operations.
There will be analog and digital data conversion modules within the system. In a controller or processor digital data is processed. It cannot process analog data. So the analog data input to the controller will pass through converter and make it digital. Again the processed digital data can be converted into analog in the output. So the system will be capable of handling any type of data.
An IC cannot work without power or voltage. In order to make this possible there will be a voltage regulator and power management system for powering the IC. The external voltage supplied is regulated and used for the working of IC. This will prevent voltage spikes entering into the device and protects it from damage.

This whole arrangement will be contained in a single chip. This is called system on chip. Future devices will be made by this technology. This will make that devices extra small.