A Microcontroller is a small and low-cost microcomputer, which is designed to perform the specific tasks of embedded systems like displaying microwave’s information, receiving remote signals etc.
The general microcontroller consists of the processor, the memory (RAM, ROM, EPROM), Serial ports, peripherals (timers, counters) etc.
Microcontrollers are divided into various categories based on memory, architecture, bits and instruction sets. Following is the list of their types
Bit − Based on bit configuration, the microcontroller is further divided into three categories.
8-bit microcontroller − This type of microcontroller is used to execute arithmetic and logical operations like addition, subtraction, multiplication division, etc. For example, Intel 8031 and 8051 are 8-bit microcontroller.
16-bit microcontroller − This type of microcontroller is used to perform arithmetic and logical operations where higher accuracy and performance is required. For example, Intel 8096 is a 16-bit microcontroller.
32-bit microcontroller − This type of microcontroller is generally used in automatically controlled appliances like automatic operational machines, medical appliances, etc.
Memory − Based on the memory configuration, the microcontroller is further divided into two categories.
External memory microcontroller − This type of microcontroller is designed in such a way that they do not have a program memory on the chip. Hence, it is named as external memory microcontroller. For example: Intel 8031 microcontroller.
Embedded memory microcontroller − This type of microcontroller is designed in such a way that the microcontroller has all programs and data memory, counters and timers, interrupts, I/O ports are embedded on the chip. For example: Intel 8051 microcontroller.
Instruction Set − Based on the instruction set configuration, the microcontroller is further divided into two categories.
CISC − CISC stands for complex instruction set computer. It allows the user to insert a single instruction as an alternative to many simple instructions.
RISC − RISC stands for Reduced Instruction Set Computers. It reduces the operational time by shortening the clock cycle per instruction.
Microcontrollers are widely used in various different devices such as -
Light sensing and controlling devices like LED.
Temperature sensing and controlling devices like microwave oven, chimneys.
Fire detection and safety devices like Fire alarm.
Measuring devices like Volt Meter.
So as a summary, we can say that It is possible to integrate on a single chip all of the blocks that are needed in a microcomputer, except the I/O devices. Such a chip is termed a microcontroller. An example is Intel 8751. A few of the blocks on the 8751 are
– 4K × 8 bits of EPROM;
– 128 × 8 bits of RAM;
– 4 numbers of 8 bit I/O ports.
It also has timers and facility for serial communication. Microcontrollers are used in a variety of instruments like washing machines, printer sharer, computer keyboards, etc. They are basically used in equipment where the size and cost are required to be very small compared to a microcomputer, and where lots of complex calculations are not needed.