A microcontroller can be described as a computer on a single integrated circuit that includes a processor core, memory, and programmable input/output peripherals. Program memory such as NOR flash or OTP ROM is also often included on the chip and normally a small amount of RAM. Microcontrollers are intended for embedded systems, rather than the microprocessors used for PCs or other universally useful applications. Microcontrollers are used as part of automatically controlled objects and gadgets, for example, automotive engine control systems, remote controls, office machines, appliances, force tools, toys and other installed structures. By reducing size and cost compared to a structure that uses a separate chip, memory, and input/output devices, microcontrollers make it prudent to digitally control many more devices and methods. Mixed-signal microcontrollers are basic and coordinate simple segments needed to control non-computerized electronic structures. Some microcontrollers can use four-bit words and operate at clock rates as low as 4 khz, for low power usage (single-digit milliwatts or microwatts).Microcontroller familiesMicrocontrollers can be classified as:• 8051 - 8-bit micro building design dependent CISC (complex instruction set computer)• PIC - 8-bit micro building design dependent RISC (reduced instruction set computer)• AVR - dependent on 8-bit micro by building design RISC (reduced instruction set computer) There are also 16-bit and 32-bit micros from the same family. According to the date of invention, the 8051 is the progenitor (date of conception = 1985), later came the PIC cams and then the AVRs. The key to insert is the 8051 to have the ability to take in...... card medium ......tb.7E = Portb.3Rs = Portb.2• From Db4 to Db7: data bus of the LCD display• E: LCD display enable pin• RS: Register selection ATMEGA16 MICROCONTROLLER: ATmega16 is a low power CMOS 8-bit Microcontroller built with AVR advanced RISC architecture. It can execute powerful instructions in a single clock cycle and can achieve speeds of up to 1 MIPS per MHz allowing system designers to minimize power consumption and increase processing speed. ATmega 16L consists of a 40-pin integrated circuit and belongs to the Mega AVR family. ATmega 16 Features and Architecture: Atmega16 features include: • 16 KB of flash memory • 1 KB of SRAM • 512 bytes of EEPROM • Available in 40-pin DIPs • 8-channel 10-bit ADC • Two timers/counters at 8 bit • One 16 bit timer/counter • 4 PWM channels • System Programmer (ISP) • Serial USART • Interface SPI • Digital-analog comparator. • Watchdog timer