Introduction aboutMicrocontroller Eng :/ Sayed Mahmoud AbdEl Rahman
What is the Microcontroller ?A microcontroller is an integrated chip that is often partof an embedded system. The microcontroller includesa CPU, RAM, ROM, I/O ports, and timers like a standardcomputer, but because they are designed to execute onlya single specific task to control a single system,they are much smaller and simplified so that theycan include all the functions required on a single chip.
Microcontroller v/s MicroprocessorMicroprocessors are used to execute big and generic applications,while a microcontroller will only be used to execute a single taskwithin one application. Some of the benefits of microcontrollersinclude the following:Cost: The cost of the part. Microcontrollers are usually very cheap,sometimes even less than $1 each.Speed: The frequency (speed) of the system clock, often stated inmegahertz (MHz) or gigahertz (GHz). Microcontrollers are typicallyslow, less than 20MHz.Power: The power dissipation of a system, measured in Watts.Microcontrollers are almost always "low-power."
Bits: This usually means the number of bits that can be processedat one time by each instruction (e.g. 8-bit, 16-bit, 32-bit, etc...).Microcontrollers are almost always 8-bit or maybe 16-bit devices.Memory: Most processors have some amount of storage on the devicefor data and program instructions. In computing systems, memory isoften hierarchical, so on-chip memory can serve different purposes.Microcontrollers typically have a limited amount of memory, lessthan 1MByte total.All-in-one: A microcontroller usually Includes of a CPU, ROM,RAM and I/O ports, built within it to execute a single and dedicatedtask. On the other hand, a microprocessor generally does not have aRAM, ROM or IO pins and generally uses its pins as a bus to interfaceto peripherals such as RAM, ROM, serial ports, digital and analog IO.
How does Microcontroller work ?Microcontroller has an input device in order to get the input and anoutput device (such as LED or LCD Display) to exhibit the finalprocess. Let us look into the illustration of how a microcontrollerworks in a Television.The Television has a remote control as an Input device and the TVscreen as the output device. The signal sent from the remote control iscaptured by the microcontroller. The microcontroller controls thechannel selection, the amplifier system and picture tube adjustmentssuch as hue, brightness, contrast etc.
General architecture of a MicrocontrollerThe architecture of a microcontroller depends on the application it isbuilt for. For example, some designs include usage of more than oneRAM, ROM and I/O functionality integrated into the package.
The architecture of a typical microcontroller is complex and may includethe following:1. A CPU, ranging from simple 4-bit to complex 64-bit processers.2. Peripherals such as timers, event counters and watchdog.3. RAM (volatile memory) for data storage. The data is stored in the form ofregisters, and the general-purpose registers store information that interactswith the arithmetic logical unit (ALU).4. ROM, EPROM, EEPROM or flash memory for program and operatingparameter storage.5. Programming capabilities (Assembly, c, c++, Basic and Pascal) .6. Serial input/output such as serial ports.7. A clock generator for resonator, quartz timing crystal or RC circuit.8. Analog-to-digital convertors.9. Serial ports.10. Data bus to carry information.
ApplicationsMicrocontrollers are used in products that are controlled automatically.The various products that make use of microcontrollers in our everydaylife are given below:1. Home: Television, DVD player, Telephone, Fax machine, Cellularphones, Security systems, Camera, Sewing machine, MusicalInstrument, Exercising machine, Video games, Computer,Microwave oven.2. Office: Computers, Printers, Telephones, Fax machine, Securitysystems.