What is a Microcontroller?
A Microcontroller is a VLSI (Very Large Scale Integration) Integrated Circuit (IC) that contains electronic computing unit and logic unit (combinedly known as CPU), Memory (Program Memory and Data Memory), I/O Ports (Input / Output Ports) and few other components integrated on a single chip.
Sometimes, a Microcontroller is also called as a Computer-on-a-Chip or a Single-Chip-Computer. Since the Microcontroller and its supporting circuitry are often embedded in the device it controls, a Microcontroller is also called as an Embedded Controller.
Microcontrollers are omnipresent. If a device or an application involves measuring, storing, calculating, controlling or displaying information, then device contains a Microcontroller in it. Let us see some of the areas where microcontrollers are used.
The biggest user of Microcontrollers is probably the Automobiles Industry. Almost every car that comes out of the assembly factory contains at least one Microcontroller for the purpose of engine control. You can find many more Microcontrollers for controlling additional systems.
Consumer Electronics is another area which is loaded with Microcontrollers. Microcontrollers are a part of Digital Cameras, Video Camcorders, CD and DVD Players, Washing Machines, Ovens, etc.
Microcontrollers are also used in test and measurement equipment like Multimeters, Oscilloscopes, Function Generators, etc. You can also find microcontrollers near your desktop computer like Printers, Routers, Modems, Keyboards, etc.
The above definitions of the Microcontroller might seem complicated or confusing to newbies in Electronics or Embedded Systems but the concept will become clear as we move forward.
First, we will see the Rise of Microcontrollers, where you can find how the development to the Microcontroller took place.
Rise of Microcontrollers
Microprocessor, the invention that took the field of computation by storm. A Microprocessor is an Integrated Circuit (IC) that contains the Central Processing Unit (CPU). The earliest known Microprocessors are the Intel’s 4004 and the Texas Instruments’ TMS1000.
Since then, the computational power, complexity and power consumption kept on increasing in order to provide ultimate performance (Power Consumption must be discussed separately due to developments such as Low Power VLSI etc.).
For a Microprocessor to work, it needs a bunch of supporting hardware that can be found on a mother board. The hardware includes memory, ICs for peripheral devices, etc.
In the beginning itself, the Microprocessors ability to control other electronic equipment like Photocopiers is realized. The emphasis here is not on the computational power of the Microprocessor but rather on a control mechanism with less complex hardware and increased reliability.
This requirement paved way for integrating the minimum hardware required for complete functioning of a Processor on to a single chip i.e. same chip as the processor, to be precise.
This is the rise of Microcontrollers, an Integrated Circuit, which contains all the functions and hardware in order to make a complete computer system. Here, the computational power of the device is of less importance than the integration of all the components, including memory.
Basics of Microcontrollers
Basically, a Microcontroller consists of the following components.
- Central Processing Unit (CPU)
- Program Memory (ROM – Read Only Memory)
- Data Memory (RAM – Random Access Memory)
- Timers and Counters
- I/O Ports (I/O – Input/Output)
- Serial Communication Interface
- Clock Circuit (Oscillator Circuit)
- Interrupt Mechanism
Most modern Microcontrollers might contain even more peripherals like SPI (Serial Peripheral Interface), I2C (Inter Integrated Circuit), ADC (Analog to Digital Converter), DAC (Digital to Analog Converter), CAN (Controlled Area Network), USB (Universal Serial Bus), and many more.
The CPU (Central Processing Unit) in a Microcontroller performs the arithmetic, logic, math and data-oriented function, similar to CPU in the Microprocessor. The difference between a Microprocessor and Microcontroller is that a Microprocessor need to be interface with external memory and other I/O Interfaces to work as a computer whereas, a Microcontroller has all the required peripherals on the same chip as the CPU.
The integration of features like ADC, DAC etc. on the same chip as the CPU makes it more efficient and cheaper than to use a separate ADC Chip.
Developing a Computer Controlled System involves design of the Hardware and also writing an efficient Software Program. Since a Microcontroller has all the hardware, that are required to make a computer controlled system on a single chip, using a Microcontroller will drastically reduce the efforts and time spent on hardware design and wiring.