8051 Microcontroller Notes • 1. Narasimha Murthy.Ph.D yayavaram@yahoo.com INTEL 8051 MICRCONTROLLERIntroduction:A decade back the process and control operations were totally implemented by theMicroprocessors only. But now a days the situation is totally changed and it is occupied by thenew devices called Microcontroller. The development is so drastic that we can’t find anyelectronic gadget without the use of a microcontroller. Swastik Accounting Software Full Version. This microcontroller changed theembedded system design so simple and advanced that the embedded market has become one ofthe most sought after for not only entrepreneurs but for design engineers also.What is a Microcontroller? A single chip computer or A CPU with all the peripherals like RAM, ROM, I/O Ports,Timers, ADCs etc. On the same chip.

2 8051 Tutorial: Types of Memory The 8051 has three very general types of memory. To effectively program the 8051 it is necessary to have a basic understanding of these. No information is available for this page.Learn why.

For ex: Motorola’s 6811, Intel’s 8051, Zilog’s Z8 andPIC 16X etcMICROPROCESSORS & MICROCONTROLLERS:Microprocessor:A CPU built into a single VLSI chip is called a microprocessor. It is a general-purpose deviceand additional external circuitry are added to make it a microcomputer. The microprocessorcontains arithmetic and logic unit (ALU), Instruction decoder and control unit, Instructionregister, Program counter (PC), clock circuit (internal or external), reset circuit (internal orexternal) and registers. But the microprocessor has no on chip I/O Ports, Timers, Memory etc.For example, Intel 8085 is an 8-bit microprocessor and Intel 8086/8088 a 16-bit microprocessor.The block diagram of the Microprocessor is shown in Fig.1 1 • Fig.1 Block diagram of a Microprocessor.MICROCONTROLLER:A microcontroller is a highly integrated single chip, which consists of on chip CPU (CentralProcessing Unit), RAM (Random Access Memory), EPROM/PROM/ROM (ErasableProgrammable Read Only Memory), I/O (input/output) – serial and parallel, timers, interruptcontroller. For example, Intel 8051 is 8-bit microcontroller and Intel 8096 is 16-bitmicrocontroller. The block diagram of Microcontroller is shown in Fig.2.

2 • Fig.2.Block Diagram of a Microcontroller 3 • Distinguish between Microprocessor and MicrocontrollerS.No Microprocessor Microcontroller1 A microprocessor is a general A microcontroller is a dedicated chip which purpose device which is called a is also called single chip computer. CPU2 A microprocessor do not contain A microcontroller includes RAM, ROM, onchip I/OPorts, Timers, Memories serial and parallel interface, timers, interrupt etc.

Circuitry (in addition to CPU) in a single chip.3 Microprocessors are most Microcontrollers are used in small, commonly used as the CPU in minimum component designs performing control-oriented applications. Microcomputer systems4 Microprocessor instructions are Microcontroller instructions are both bit mainly nibble or byte addressable addressable as well as byte addressable.5 Microprocessor instruction sets are Microcontrollers have instruction sets mainly intended for catering to catering to the control of inputs and large volumes of data. Outputs.6 Microprocessor based system Microcontroller based system design is design is complex and expensive rather simple and cost effective7 The Instruction set of The instruction set of a Microcontroller is microprocessor is complex with very simple with less number of large number of instructions. For, ex: PIC microcontrollers have only 35 instructions.8 A microprocessor has zero status A microcontroller has no zero flag. FlagEVOLUTION OF MICROCONTROLLERS: 4 • The first microcontroller TMS1000 was introduced by Texas Instrumentsin the year1974. In the year 1976, Motorola designed a Microprocessor chip called 6801 which replacedits earlier chip 6800 with certain add-on chips to make a computer. This paved the way for thenew revolution in the history of chip design and gave birth to a new entity called“Microcontroller”.

Later the Intel company produced its first Microcontroller 8048 with aCPU and 1K bytes of EPROM, 64 Bytes of RAM an 8-Bit Timer and 27 I/O pins in 1976. Thenfollowed the most popular controller 8051 in the year 1980 with 4K bytes of ROM,128 Bytes ofRAM, a serial port, two 16-bit Timers, and 32 I/O pins. The 8051 family has many additionsand improvements over the years and remains a most acclaimed tool for today’s circuitdesigners. INTEL introduced a 16 bit microcontroller 8096 in the year 1982. Later INTELintroduced 80c196 series of 16-bit Microcontrollers for mainly industrial applications.Microchip, another company has introduced an 8-bit Microcontroller PIC 16C64 in the year1985.The 32-bit microcontrollers have been developed by IBM and Motorola.

MPC 505 is a 32-bit RISC controller of Motorola.

Every now and again we take a look around at the 8051 microcontroller to select the best tutorials, simulators, compilers, programmers and present them to you in a brief overview. The choice is enormous, so the time you need to find all these resources is usually the time you should be investing in your current projects. We search for them, and we find them, so you can have it in one place. 8051 is not just a random number; it’s the name of one of the most frequently used microcontroller in robotics. This single chip microcontroller is a very small black piece where are stored functions like CPU, RAM, ROM, Timer, Serial Communication Interface, I/O ports, etc. The first version was presented in the 1980s, and since then the microcontroller has been embedded in a large variety of robotics projects. The 8051 microcontroller is a small computer based on an architecture with support for embedded applications.