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Characteristics [ to publish ] They are designed to diminish the economic cost and the consumption of energy of a system in individual. For that reason the size of the CPU, the amount of memory and the peripheral ones including will depend on the application. The household-electric control of a simple one like a beater, will use a very small processor (4 or 8 bit) so that it will replace a finite robot. However a reproducer of music and/or digital video (mp3 or mp4) will require of a processor of 32 bit or 64 bit and one or but Códec of DS (audio and/or video). The control of a system of brakes ABS (Antilock Brake System) is based normally on a microcontroller of 16 bit, like the system of electronic control of the motor in an automobile. Scheme of a microcontroller Scheme of a microcontroller The microcontrollers represent the immense majority of the Chips of sold computers, on a 50% they are “simple” controllers and the specialized rest corresponds more to DSPs. While one or two can be had microprocessors of general intention in house (you it is using one for this), you have surely distributed between household-electric of your home one or two dozens of microcontroller. They can be in almost any electrical device like automobiles, washing machines, furnaces microwaves, telephones, etc… A microcontroller differs from a normal CPU, because it is easier to turn it a computer in operation, with a minimum of support Chips external. The idea is that the chip is placed in the device, hooked to the information and power plant that needs, and that is everything. A traditional microprocessor will not allow him to do this, since it hopes that all these tasks are handled by other Chips. It is necessary to add the modulos of input/output (ports) and the memory to him for information storage. For example, a typical microcontroller will have a generator of integrated clock and a small amount of ram memory and ROM/EPROM/EEPROM/FLASH, meaning that stops to make it work, everything what it is needed is few control programs and a crystal of synchronization. The microcontrollers generally also have a great variety of input/output devices, like converters of analogical to digitalis, timers, UARTs and bus of specialized interface series, like I2C and DOG. Frequently, these integrated devices can be controlled by instructions of specialized processors. The modern microcontrollers frequently include an integrated programming language, like the BASIC that is used enough with this intention. The microcontrollers negotiate the speed and the flexibility to facilitate their use. Because enough site in the chip is used to include functionality, like the devices of input/output or the memory that includes the microcontroller, it has itself to do without any other circuitry.

Programmed system is an electronic circuit that a microprocessor or a microcontroller integrated in the same one contains. By means of a stored computer science program in an internal memory, it is made the control and the management of the system. This type of circuits is, functionally, identical to a system wiring, with the fundamental difference that in a programmed system, modifying his logical operation it is reduced to a simple change of the program (software) of the microprogrammed circuit, with the reduction of costs that it supposes. To make a similar change in a system wiring requires a partial or complete change of its physical structure (cables or components that contains). Of this form, automatism that they use a programmed system are less expensive to reuse than those that are constituted by a system wiring. The main disadvantages of this type of systems are: * Speed * Cost The speed of a programmed system can be a problem depending on the critical velocity of the complete system. If a system must “respond” before a signal of entrance with a time of reaction very reduced (of the order of microseconds or less) it is possible that a programmed system has a too high cost to fulfill this requirement. In most of the cases this it is not necessary. At the present time, the cost is every time a smaller problem due to the diminution of the production costs as a result of the great demand of the digital electronics in the world. Nevertheless, for very simple systems, with a very concrete functionality, it can turn out more expensive to use a programmed system.

The digital electronics is a part of the electronics that is in charge of electronic systems in which the information is codified in two only states. To these states it is possible to be called to them “true” or “false”, or more commonly 1 and 0. Electronically a voltage or rank of determined voltage is assigned to them to each one, to which it denominates logical levels to them, typical in all DS. Difference of the analogical electronics in which, for the digital electronics a value of voltage codifies one of these two states, whereas for the analogical electronics there is a infinity of information states that to codify according to the value of the voltage. This particularitity allows that, using Boolean Algebra and a binary system of numeration, complex operations can be made logics or Arithmetics on the entrance signals, very expensive to do using analogical methods. The digital electronics has reached a great importance because it is used to make robots and being the angular stone of the microprogrammed systems as they are the computers or computers.

One says that a signal is digital when the magnitudes of the same one imagine by means of discreet values instead of continuous variables. For example, the switch of the light only can take two values or states: opened or closed, or the same lamp: ignited or extinguished (it see circuit of commutation). The digital systems, like for example the computer, use logic of two states represented by two levels of electrical tension, one stop, H and low other, L (of High and Low, respectively, in English). By abstraction, these states are replaced by zeros and, which facilitates the application of the logic and the binary Arithmetic. If the high level imagines by the 1 and low one by 0, speech of positive logic and in opposite case of negative logic. It is possible to mention that in addition to the levels, in a DS are the transitions of stop to low or low to stop, denominated slope or ascent flank, respectively. In the following figure is a DS where the levels and the flanks are identified. DS: 1) low Level, 2) high Level, 3) Flank of ascent and 4) Flank of slope. DS: 1) low Level, 2) high Level, 3) Flank of ascent and 4) Flank of slope. He is advisable to clarify that, although in the indicated examples the digital term has been always related to binary devices, it does not mean that digital and binary they are interchangeable terms. For example, if we paid attention to the Morse code, we will see that in him they are used, for the shipment of messages by electrical telegraph, five digital states that are: point, ray, short space (between letters), space average (between words) and long space (between phrases) Referred to an apparatus or instrument of measurement, we say that it is digital when the result of the measurement imagines in a visualizer by means of numbers (digits) instead of doing it by means of the position of a needle, or any other indicator, in a scale.