Each of these systems will use a microcontroller as their main operate unit:
- Car lock remote key fob.
- Tv Remote control.
- Security system.
- Electronic safe.
- Car anti lock braking system.
- Satelite decoder.
- Dvd player.
- Toaster.
A microcontroller is an all in one electronic integrated circuit with built in processor memory and peripherals that is also re-programmable.
You may not be able to recognize the microcontroller as for cost savings its economy to build an Asic (Application exact Integrated Circuit). This is a custom chip designed only for the goods which is mass produced in milliions production the cost of the device far economy than using an individual microcontroller.
Nevertheless each theory is based on a microcontroller.
Electronic Circuit invent has progressed from individual transistors which are based on silicon to placing thousands and then millions of transistors on a single silicon wafer. The transistors, arranged in the exact configuration, accomplish different functions such as time delays, boolean logic, memory etc.
7400 series logic
Still ready today are the older 74 series devices. These are Ics encased in plastic with connection pins on the outside and each one performs a different well defined function.
By grouping these devices together you can make up circuits by connecting the pins of the device to pins of other devices. About 20 years ago this was the only way of production digital electronic systems and you would typically have racks of circuit boards each with 50 of these devices wired up.
More transistors
Of procedure the disadvantage of these racks of circuit boards is that once you have designed the board you can not convert it so you had to be no ifs ands or buts sure that the invent was perfect. If it was not then you had to start over - and for a complicated theory that means spending money on a new circuit board and spending time re-designing it.
With the progress of manufacturing techniques more transistors can be put on the silicon wafer - and if you can get more transistors on a wafer there are two advantages.
- Increased functionalty.
- Higher speed.
Smaller transistors means smaller corporal problems (capacitance slows down a devcie - so a smaller device has less) and they also use less current. Less current means less power and less power means less heat and less heat means that the device can operate faster.
Given adequate transistors you can invent a circuit (or Integrated Circuit - Ics) to accomplish virtually any function you can think and using a extra form of transistor (flash memory) means that the device can store facts for years - this memory is also re-programmable.
Processor
The next stage in amelioration was creating the processor which is a specialised circuit in which the function of the device is not set at all. Instead the device is capable of performing different functions when it is given different inputs and not only that - it has a small estimate of ram inside used for internal temporary storage (registers) - and this lets it remember a sequence of events.
When you incorporate this device with two types external memory (other Ics) you can make a theory that can consequent a defined sequence of events. By reading instructions from the memory (Rom) the processor knows what it should be doing as its next event sequence and it can store data in external Ram memory.
- Rom - Read Only Memory (permament)
- Ram - Random passage memory (temporary - when power goes info is lost).
In expanding the processor can read the state of input pins and set the state of production pins so it can react to the outside world e.g. Turn on a light or read a key press.
You can see where this is going - it's a device that has re-programmable memory and has many of the construction blocks (7400 series) although now greatly refined and adapted inside the device - it's the microcontroller.
Microcontrollers
A microcontroller is a specialized integrated circuit which combines a processor and external memory inside the silicon wafer itself. You now have a customizable device that you can convert its function just by re-programming it.
In expanding as microcontrollers have been refiined you will find devices that have many other peripherals inside them. Where once you had to buy a Uart Ic (an Rs232 transportation device - to talk to a Pc) and place it on the processor bus in expanding to the Ram and the Rom; this device is now part of the microcontroller itself.
Here are the internal peripherals of the 16F88 a contemporary Pic microcontroller - this is just an example there are many more microcontroller manufacturers e.g. Atmel, Motorola, Zilog.
- Ram 386 Bytes.
- Rom 4096 words.
- Eeprom 256 Bytes.
- I/O 16 pins.
- Internal oscillator.
- Timer 1.
- Timer 2.
- Timer 3.
- Usart. Ssp - Synchronous Serial port I2C, Spi protocols.
- Ccp - Capture assess Pwm.
- Analogue comparator 1.
- Analogue comparator 2.
- Adc multiplexed inputs from 7 pins.
This an 18 pin Ic which is as big as some of the former 7400 devices but it can do much more that those single chips. For instance you can make the following types of projects using it:
- Universal Infrared decoder/encoder.
- Ultrasonic tape measure.
- Frequency counter.
- Metal detector.
Note: All of these projects can be made using the same device because you can re-program the microcontroller to do a different job.
You can find more facts here: microcontroller information and how to build a website that gets the click.
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