Pin diagram of 40 pin Intel 8051 Microcontroller

The Intel 8051 was a Harvard architecture single chip microcontroller (µC) developed by Intel in 1980 for use in embedded systems. It was extremely popular in the 1980s and early 1990s, but today it has largely been superseded by a vast range of enhanced devices with 8051-compatible processor cores that are manufactured by more than 20 independent manufacturers including Atmel, Maxim IC (via its Dallas Semiconductor subsidiary), Philips, Winbond, and Silicon Laboratories. Intel's official designation for the 8051 family of µCs is MCS 51. Image File history File links 77le58_p. ... Image File history File links 77le58_p. ... The term Harvard architecture originally referred to computer architectures that used physically separate storage and signal pathways for their instructions and data (in contrast to the von Neumann architecture). ... A microcontroller (or MCU) is a computer-on-a-chip used to control electronic devices. ... Intel Corporation (NASDAQ: INTC, SEHK: 4335), founded in 1968 as Integrated Electronics Corporation, is a U.S.-based multinational corporation that is best known for designing and manufacturing microprocessors and specialized integrated circuits. ... 1980 (MCMLXXX) was a leap year starting on Tuesday. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... 2006 is a common year starting on Sunday of the Gregorian calendar. ... Atmel Corporation (NASDAQ: ATML) is a manufacturer of semiconductors, founded in 1984. ... Maxim Integrated Products (including its subsidiary Dallas Semiconductor) is a semiconductor company that designs and manufactures analog and mixed-signal integrated circuits. ... This article needs cleanup. ... Koninklijke Philips Electronics N.V. (Royal Philips Electronics N.V.), usually known as Philips, (Euronext: PHIA, NYSE: PHG) is one of the largest electronics companies in the world. ... Winbond Electronics Corporation is a Taiwan-based corporation which was founded in 1987 and is a producer of semiconductors and several types of integrated circuits, most notably Dynamic RAM, Static RAM and microcontrollers. ...

Intel's original 8051 family was developed using NMOS technology, but later versions, identified by a letter "C" in their name, e.g. 80C51, used CMOS technology and were less power-hungry than their NMOS predecessors - this made them eminently more suitable for battery-powered devices. nMOS logic uses n-type metal-oxide-semiconductor field effect transistors (MOSFETs) to implement logic gates and other digital circuits. ... Static CMOS Inverter CMOS (see-moss), which stands for complementary metal-oxide semiconductor, is a major class of integrated circuits. ...

Important Features of 8051 :

• It contains Processor (CPU), RAM, ROM, Serial Port , Parallel Port, Interrupt logic, Timer etc.
• Data Bus - 8 bit data bus. Can access 8 bit data in one operation. Hence called 8-bit microprocessor.
• Address Bus - 16 bit address bus. Can access 2¹⁶ memory locations i.e 64 KB of memory each of RAM and ROM.
• On chip RAM - 128 Bytes (Data Memory).
• On chip ROM - 4 KB (Program Memory).
• Four Bit bi-directional Input Output port.
• Serial Port.
• Two 16 - bit Up-Counter.
• Two level interrupt priority.
• Power saving mode.

A particularly useful feature of the 8051 core is the inclusion of a boolean processing engine which allows bit-level boolean logic operations to be carried out directly and efficiently on internal registers and RAM. This feature helped to cement the 8051's popularity in industrial control applications. Another valued feature is that it has four separate register sets, which can be used to greatly reduce interrupt latency compared to the more common method of storing interrupt context on a stack. CPU can stand for: in computing: Central processing unit in journalism: Commonwealth Press Union in law enforcement: Crime prevention unit in software: Critical patch update, a type of software patch distributed by Oracle Corporation in Macleans College is often known as Ash Lim. ... Sharma Ram (disambiguation) Ram Sharma is an amazing, talented teenager that lives in Canada His talents include rapping, comedy, and cooking He is bound to success! ... Read-only memory (ROM) is a class of storage media used in computers and other electronic devices. ... A male DE-9 serial port on the rear panel of a PC. A male serial port on a laptop computer. ... In computing, a parallel port is an interface from a computer system where data are transferred in or out in parallel, that is, on more than one wire. ... In computer science, an interrupt is an asynchronous signal from hardware or software indicating the need for attention. ... A timer is a specialized type of clock. ... 8-bit refers to the number of bits used in the data bus of a computer. ... Microprocessors, including an Intel 80486DX2 and an Intel 80386. ... The abbreviation KB can refer to: Kilobyte (kB), equal to 1,000 bytes, or Kibibyte (KiB), equal to 1,024 bytes. ... Sharma Ram (disambiguation) Ram Sharma is an amazing, talented teenager that lives in Canada His talents include rapping, comedy, and cooking He is bound to success! ... Read-only memory (ROM) is a class of storage media used in computers and other electronic devices. ... Sharma Ram (disambiguation) Ram Sharma is an amazing, talented teenager that lives in Canada His talents include rapping, comedy, and cooking He is bound to success! ... This article refers to the unit of binary information. ... Read-only memory (ROM) is a class of storage media used in computers and other electronic devices. ... The abbreviation KB can refer to: Kilobyte (kB), equal to 1,000 bytes, or Kibibyte (KiB), equal to 1,024 bytes. ... This article is about the unit of information. ... A male DE-9 serial port on the rear panel of a PC. A male serial port on a laptop computer. ... In computer science, an interrupt is an asynchronous signal from hardware or software indicating the need for attention. ... In computer science the boolean datatype, sometimes called the logical datatype, is a primitive datatype having two values: one and zero (sometimes called true and false). ... This article is about the unit of information. ... Boolean logic is a complete system for logical operations. ... In computer architecture, a processor register is a small amount of very fast computer memory used to speed the execution of computer programs by providing quick access to commonly used values—typically, the values being in the midst of a calculation at a given point in time. ... Interrupt latency is the time between the generation of an interrupt by a device and the servicing of the device which generated the interrupt. ... A context switch is the computing process of storing and restoring the state of a CPU (the context) such that multiple processes can share a single CPU resource. ...

The 8051 UART can be configured to use a 9th data bit that can provide addressable communications in an RS-485 multi-point communications environment. A UART or universal asynchronous receiver-transmitter is a piece of computer hardware that translates between parallel bits of data and serial bits. ... EIA-485 (formerly RS-485 or RS485) is an OSI Model physical layer electrical specification of a two-wire, half-duplex, multipoint serial connection. ...

8051 based microcontrollers typically include one or two UARTs, two or three timers, 128 or 256 bytes of internal data RAM (16 bytes of which are bit-addressable), up to 128 bytes of I/O, 512 bytes to 128kb of internal program memory, and sometimes a quantity of extended data RAM (ERAM) located in the program address space. The original 8051 core ran at 12 clock cycles per machine cycle, with most instructions executing in one or two machine cycles. With a 12 MHz clock frequency, the 8051 could thus execute 1 million one-cycle instructions per second or 500,000 two-cycle instructions per second. Enhanced 8051 cores are now commonly used which run at six, four, two, or even one clock per machine cycle, and have clock frequencies of up to 100 MHz, and are thus capable of an even greater number of instructions per second. All SILabs, some Dallas and a few Atmel devices have single cycle cores. A UART or universal asynchronous receiver-transmitter is a piece of computer hardware that translates between parallel bits of data and serial bits. ... Sharma Ram (disambiguation) Ram Sharma is an amazing, talented teenager that lives in Canada His talents include rapping, comedy, and cooking He is bound to success! ... In computing, Input/output, or I/O, is the collection of interfaces that different functional units (sub-systems) of an information processing system use to communicate with each other, or the signals (information) sent through those interfaces. ... In synchronous digital electronics, such as most computers, a clock signal is a signal used to coordinate the actions of two or more circuits. ...

Even higher speed single cycle 8051 cores, in the range 130 MHz to 150 MHz, are now available in internet downloadable form for use in programmable logic devices such as FPGAs, and at many hundreds of MHz in ASICs, for example the netlist from e8051.com. A programmable logic device or PLD is an electronic component used to build digital circuits. ... A field-programmable gate array or FPGA is a gate array that can be reprogrammed after it is manufactured, rather than having its programming fixed during the manufacturing — a programmable logic device. ... ASICS (アシックス; TYO: 7936 ) is an athletic shoe company that started in 1949 when Kihachiro Onitsuka began manufacturing basketball shoes at his home in Kobe, Hyogo Prefecture, Japan. ... The word netlist can be used in several different domains, but perhaps the most popular is in the electronic design domain. ...

Common features included in modern 8051 based microcontrollers include built-in reset timers with brown-out detection, on-chip oscillators, self-programmable Flash ROM program memory, bootloader code in ROM, EEPROM non-volatile data storage, I2C, SPI, and USB host interfaces, PWM generators, analog comparators, A/D and D/A converters, RTCs, extra counters and timers, in-circuit debugging facilities, more interrupt sources, and extra power saving modes. Flash memory is a form of EEPROM that allows multiple memory locations to be erased or written in one programming operation. ... I2C (for Inter-Integrated Circuit, pronounced I-squared-C) is a serial computer bus invented by Philips. ... The Serial Peripheral Interface Bus or SPI bus is a very loose standard for controlling almost any digital electronics that accepts a clocked serial stream of bits. ... Note: USB may also mean upper sideband in radio. ... Pulse-width modulation of a signal or power source involves the modulation of its duty cycle, to either convey information over a communications channel or control the amount of power sent to a load. ... This article or section should include material from AD converters In electronics, an analog-to-digital converter (abbreviated ADC, A/D, or A to D) is a device that converts continuous signals to discrete digital numbers. ... In electronics, a digital-to-analog converter (DAC or D-to-A) is a device for converting a digital (usually binary) code to an analogue signal (current, voltage or charges). ... A real-time clock (RTC) is a computer clock (most often in the form of an integrated circuit chip) that keeps track of the current time even when the computer is turned off. ...

Several C compilers are available for the 8051, most of which feature extensions that allow the programmer to specify where each variable should be stored in its six types of memory, and provide access to 8051 specific hardware features such as the multiple register banks and bit manipulation instructions. Other high level languages such as Forth, BASIC, PASCAL, PL/M and Modula 2 are available for the 8051, but they are less widely used than C and assembly. The C Programming Language, Brian Kernighan and Dennis Ritchie, the original edition that served for many years as an informal specification of the language The C programming language (often, just C) is a general-purpose, procedural, imperative computer programming language developed in the early 1970s by Dennis Ritchie for use... Forth is a procedural, stack-oriented, reflective programming language and programming environment. ... BASIC (Beginners All-purpose Symbolic Instruction Code) is a family of high-level programming languages. ... The pascal (symbol: Pa) is the SI unit of pressure. ... The PL/M programming language (an acronym of Programming Language for Microcomputers) is a medium-level language developed by MAA (later Digital Research) in 1972 on behalf of Intel for its microprocessors. ... Modula-2 is a computer programming language invented by Niklaus Wirth at ETH around 1978, as a successor to Modula, another language by him. ... It has been suggested that Assembler be merged into this article or section. ...

The 8051's predecessor, the 8048, was used in the keyboard of the first IBM PC, where it converted keypresses into the serial data stream which is sent to the main unit of the computer. The 8048 and derivatives are still used today for basic model keyboards. The Intel 8048 microcontroller (µC), Intels first µC, was used in the Magnavox Odyssey² video game console and (in its 8042 variant) in the original IBM PC keyboard. ... IBM PC (IBM 5150) with keyboard and green screen monochrome monitor (IBM 5151), running MS-DOS 5. ... 2006 is a common year starting on Sunday of the Gregorian calendar. ...

The 8031 was a cut down version of the original Intel 8051 that did not contain any internal program memory.

The 8052 was an enhanced version of the original Intel 8051 that featured 256 bytes of internal RAM instead of 128 bytes, 8 kB of ROM instead of 4 kB, and a third 16-bit timer. The 8032 had these same features except for the internal ROM program memory. The 8052 and 8032 are largely considered to be obsolete because these features and more are included in nearly all modern 8051 based microcontrollers.

External links

• 8051 Forum
• e8051 netlist download
• Microcontroller.com
• 8051 Tutorial (8052.com)
• Official 8051 FAQ
• Intel MCS 51 series microcontrollers
• Maxim/Dallas 8051 Drop-In microcontrollers
• Open Core 8052 Cores with and without Wishbone bus
• 8051 Macro Assembler ASEM-51
• SDCC, a free open-source C compiler
• Free resources for 8051 and other development tools
• 8051 assembler

The Wishbone Bus is an open source computer bus intended to let parts of an integrated circuits communicate with each other. ...

List of Intel microcontrollers

MCS-48 (8048 family) | MCS-51 (8051 family) | 8061 | MCS-96 (8096 family) | (80186) | (80188) | 80376 | 80386EX | i960 (80960) (italics indicate non-x86-architecture controllers) Intel logo, claiming fair use This is a copyrighted and/or trademarked logo. ... A microcontroller (or MCU) is a computer-on-a-chip used to control electronic devices. ... The Intel 8048 microcontroller (µC), Intels first µC, was used in the Magnavox Odyssey² video game console and (in its 8042 variant) in the original IBM PC keyboard. ... The Intel 8061 microcontroller is most notable for its use in the Ford EEC-IV automotive engine control unit. ... An Intel 80186 Microprocessor The 80186 architecture. ... The Intel 80188 is a version of the Intel 80186 microprocessor with an 8 bit external data bus, instead of 16 bit. ... The Intel 80376, introduced January 16, 1989, was a variant of the Intel 80386 intended for embedded systems. ... The Intel 80386EX (386EX) is a variant of the Intel 386 microprocessor designed for embedded systems. ... Intels i960 (or 80960) was a RISC-based microprocessor design that became quite popular during the early 1990s as an embedded microcontroller, for some time likely the best-selling CPU in that field, pushing the AMD 29000 from that spot. ... x86 or 80x86 is the generic name of a microprocessor architecture first developed and manufactured by Intel. ...