FACTOID # 29: 73.3% of America's gross operating surplus in motion picture and sound recording industries comes from California.
 
 Home   Encyclopedia   Statistics   States A-Z   Flags   Maps   FAQ   About 
   
 
WHAT'S NEW
 

SEARCH ALL

FACTS & STATISTICS    Advanced view

Search encyclopedia, statistics and forums:

 

 

(* = Graphable)

 

 


Encyclopedia > Intel 8080
Intel 8080
Central processing unit

An Intel C8080A processor.
Produced: mid 1974
Manufacturer: Intel
CPU Speeds: 2 MHz
Instruction Set: pre x86
Socket: 40 pin DIP
AMD clone
AMD clone
NEC 8080AF (2nd-source).
NEC 8080AF (2nd-source).

The Intel 8080 was an early microprocessor designed and manufactured by Intel. The 8-bit CPU was released in April 1974 running at 2 MHz, and is generally considered to be the first truly usable microprocessor CPU design. It was implemented in NMOS. Die of an Intel 80486DX2 microprocessor (actual size: 12×6. ... Wikipedia does not have an article with this exact name. ... Intel Corporation (NASDAQ: INTC, SEHK: 4335), founded in 1968 as Integrated Electronics Corporation, is an American multinational corporation that is best known for designing and manufacturing microprocessors and specialized integrated circuits. ... Die of an Intel 80486DX2 microprocessor (actual size: 12×6. ... A megahertz (MHz) is one million (106) hertz, a measure of frequency. ... It has been suggested that some sections of this article be split into a new article entitled instruction set architecture. ... x86 or 80x86 is the generic name of a microprocessor architecture first developed and manufactured by Intel. ... ICs in DIP14-Package Several PDIPs and CERDIPS. The large CERDIP in the foreground is an 8080 processor. ... Wikipedia does not have an article with this exact name. ... Wikipedia does not have an article with this exact name. ... Advanced Micro Devices, Inc. ... Image File history File links A NEC 8080AF microprocessor. ... Image File history File links A NEC 8080AF microprocessor. ... NEC Corporation (Jp. ... A microprocessor is a programmable digital electronic component that incorporates the functions of a central processing unit (CPU) on a single semiconducting integrated circuit (IC). ... Intel Corporation (NASDAQ: INTC, SEHK: 4335), founded in 1968 as Integrated Electronics Corporation, is an American multinational corporation that is best known for designing and manufacturing microprocessors and specialized integrated circuits. ... 8-bit refers to the number of bits used in the data bus of a computer. ... Die of an Intel 80486DX2 microprocessor (actual size: 12×6. ... MegaHertz (MHz) is the name given to one million (106) Hertz, a measure of frequency. ... nMOS logic uses n-type metal-oxide-semiconductor field effect transistors (MOSFETs) to implement logic gates and other digital circuits. ...

Contents

Description

Programming model

The Intel 8080 was the successor to the Intel 8008; this was due to its being assembly language source-compatible, since it used the same instruction set developed by Computer Terminal Corporation. The 8080's large 40 pin DIP packaging permitted it to provide a 16-bit address bus and an 8-bit data bus, allowing easy access to 64 kilobytes of memory. Intel 8008 The Intel 8008 was an early microprocessor designed and manufactured by Intel and introduced in April, 1972. ... See the terminology section, below, regarding inconsistent use of the terms assembly and assembler. ... In computing, a device (usually a computer processor) that can run the same source code intended to be compiled and run on another device is said to be source-compatible. ... It has been suggested that some sections of this article be split into a new article entitled instruction set architecture. ... Datapoint Corporation, originally known as Computer Terminal Corporation (CTC), was a computer company based in San Antonio, Texas. ... ICs in DIP14-Package Several PDIPs and CERDIPS. The large CERDIP in the foreground is an 8080 processor. ... An address bus is (part of) a computer bus, used by CPUs or DMA-capable units for communicating the physical addresses of computer memory elements/locations that the requesting unit wants to access (read/write). ... In computer architecture, a bus is a subsystem that transfers data or power between computer components inside a computer or between computers. ... A kilobyte (derived from the SI prefix kilo-, meaning 1000) is a unit of information or computer storage equal to the decimal 1024 bytes (2 to the 10th power, or 1,024 bytes based in the binary system). ...


Registers

The processor had seven 8-bit registers, six of which could be combined into three 16-bit register pairs (BC, DE and HL). It also had the 8-bit accumulator, the 16-bit stack pointer to memory (replacing the 8008's internal stack), and a 16-bit program counter. 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. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... Simple representation of a stack In computer science, a stack is a temporary abstract data type and data structure based on the principle of Last In First Out (LIFO). ... The program counter (also called the instruction pointer in some computers) is a register in a computer processor which indicates where the computer is in its instruction sequence. ...


Commands

Most of the 8-bit operations were possible between the accumulator and either one of the registers or the memory cell, indexed by the 16-bit value of the register pair HL. Moving operations were supported between any two registers, or between any register and the HL-indexed memory cell. Due to the highly regular machine code format for MOV commands, the opcodes included those for moving a byte from a given register into the same register (MOV A,A , for instance). These commands were seldom used, however, unless programmed delays were needed. What would have been instruction to move from the HL-indexed memory cell into the same memory cell (i.e., MOV M,M) instead was HLT (for halt). HLT halted the processor until external reset or interrupt signals were received. In a computer CPU, an accumulator is a register in which intermediate arithmetic and logic results are stored. ... In computer science and more specifically the x86 arthitecture, HLT is an assembly language instruction which halts the CPU until the next external interrupt is fired, often times this is the clock. ... In computer science and more specifically the x86 arthitecture, HLT is an assembly language instruction which halts the CPU until the next external interrupt is fired, often times this is the clock. ...


All processor commands were coded by one byte, but some of them were followed by one or two bytes of data, a memory address, or a port number. The register-to-register data-move commands were all coded by one byte, making up about a quarter of the commands in the processor-command system. The processor had 8 commands to call the subroutines located at the fixed addresses at the beginning or the address space (RST). These commands were frequently used in the interrupt-handling or system-library calls.


The most sophisticated command (and the longest to execute) was XTHL, which was used for exchanging the register pair HL with the value stored at the address indicated by the stack pointer.


16-bit operations

Despite the fact that the 8080 was generally an 8-bit processor, it was also able to load immediate any register pair (LXI), increment or decrement any register pair (INX, DCX), add the register pairs (DAD), switch HL with DE (XCHG) and perform the 16-bit arithmetical shift (DAD H) with one command. Hence some 16-bit operations were already possible.


Input/output scheme

Input output port space

The 8080 supported up to 256 input/output (I/O) ports, accessed from programs via dedicated I/O instructions—each instruction taking an I/O port address as its operand. This scheme—using a separate I/O address space—is now less commonly used than memory mapping of I/O ports/devices. At the time of the 8080's launch, this I/O mapping scheme was seen as an advantage, as it freed up the processor's limited number of address pins for the memory address space. In most other CPU architectures, however, the mapping of I/O ports in a common address space both for memory and I/O, gave a simpler instruction set; no need for separate I/O instructions. The 8080-style I/O port scheme continued into the Intel 8085 and x86 families of microprocessors. Energy Input: The energy placed into a reaction. ... Memory-mapped I/O (MMIO) and port I/O (also called port-mapped I/O or PMIO) are two complementary methods of performing input/output between the CPU and I/O devices in a computer. ... The Intel 8085 was an 8-bit microprocessor made by Intel in the mid-1970s. ... x86 or 80x86 is the generic name of a microprocessor architecture first developed and manufactured by Intel. ...


Stack space

One of the bits in the processor state word (see below) was indicating that the processor is accessing data from the stack. Using this signal, it was possible to implement a separate stack memory space. However this feature was seldom used.


Shared memory implementations

The 8080 has shared control signals for reading and writing both memory and I/O ports. In basic computers, the 8080 was frequently connected using a shared memory map, accessing ports as memory cells. In such machines, the specialised I/O commands were either not used or, in applications with little memory, were used knowing that the processor would clone the 8-bit port address to a higher address byte (IN 0x05 would produce 0x0505 on the 16-bit address bus).


The internal state word

For more advanced systems, during one phase of its working loop the processor set its "internal state byte" on the data bus. This byte contains flags which indicate whether the memory or I/O port is accessed and whether it was necessary to handle an interrupt.


The interrupt system state (enabled or disabled) was also output on a separate pin. For simple systems, where the interrupts were not used, it is possible to find cases where this pin is used as an additional single-bit output port (the popular Radio86RK computer made in USSR, for instance).


Pin usage

The address bus had its own 16 pins, and the data bus had 8 pins that were possible to use without any multiplexing. Using the two additional pins (read and write signals), it was possible to assemble simple microprocessor devices very easily. Only the separate IO space, interrupts and DMA required additional chips to decode the processor pin signals. However the processor load capacity was limited, and even simple computers frequently contained bus amplifiers.


The processor required three power sources (-5, +5 and +12 Volt(V)) and two non-interlacing high-amplitude synchronization signals. However at least the late Soviet version КР580ВМ80А was able to work with the single +5 V power source, +12 V pin being connected to the same +5 V and -5 V pin - to the ground. The processor consumed about 1.3 watts (W) of power.


The pinout table, from the chip's accompanying documentation, described the pins as follows:

Pin number Signal Type Comment
1 A10 Output Address bus 10
2 GND - Ground
3 D4 Bidirectional Bidirectional data bus. The processor also transiently sets here the "processor state", providing information that the processor is currently doing:
  • D0 reading interrupt command. In response to the interrupt signal, the processor was reading and executing a single arbitrary command with this flag raised. Normally the supporting chips provided the subroutine call command (CALL or RST), transferring control to the interrupt handling code.
  • D1 reading (low level means writing)
  • D2 accessing stack (probably the separate stack memory space was initially planned)
  • D3 doing nothing, has been halted by the HLT command
  • D4 writing data to the output port
  • D5 reading the first byte of the executable command
  • D6 reading data from the input port
  • D7 reading data from memory
4 D5
5 D6
6 D7
7 D3
8 D2
9 D1
10 D0
11 -5 V - The -5 V power supply. This must be the first power source connected and the last disconnected, otherwise the processor will be damaged.
12 R Input Reset. The signal forces execution of commands, located at address 0000. The content of other processor registers is not modified. This is an inverting input (the active level being logical 0)
13 DMA Input Direct memory access request. The processor is requested to switch the data and address bus to the high impedance ("disconnected") state.
14 INT Input Interrupt request
15 CLC2 Input The second phase of the clock generator signal
16 ACK INT Output The processor had two commands for setting the 0 or 1 level on this pin. The pin normally was supposed to be used for the interrupt control. However in the simple computers it was sometimes used just as the single bit output port for various purposes.
17 RD Output Read (the processor reads from memory or input port)
18 WR Output Write (the processor writes to memory or output port). This is the inverted output, the active level being logical zero.
19 S Output The active level indicates that the processor has set the "state word" on the data bus. The various bits of this state word provided the additional information for supporting the separate address and memory spaces, interrupts and direct memory access. This signal required to pass through additional logic before it could be used to write the processor state word from the data bus into some register.
20 5 V - The + 5 V power supply

21 ACK DMA Output Direct memory access confirmation. The processor switches data and address pins into the high impedance state, allowing other device to manipulate the bus
22 CLC1 Input The first phase of the clock generator signal
23 RDY Input Wait. With this signal it was possible to suspend processor's work. It was also used to support the hardware-based step-by step debugging mode.
24 WAIT Output Wait (indicates that the processor is in the waiting state)
25 A0 Output Address bus
26 A1
27 A2
28 12 V - The +12 V power supply. This must be the last connected and first disconnected power source.
29 A3 Output The address bus, can switch into high impedance state on demand
30 A4
31 A5
32 A6
33 A7
34 A8
35 A9
36 A15
37 A12
38 A13
39 A14
40 A11

Literature, used for this table: In computer science and more specifically the x86 arthitecture, HLT is an assembly language instruction which halts the CPU until the next external interrupt is fired, often times this is the clock. ...

  • http://tehno-doc.nm.ru/mikroshem_rus/kr580/kr580vm80a.html
  • http://www.radiomaster.ru/stati/radio/k580/14_k580.php

Physical implementation

The 8080 integrated circuit was manufactured in a NMOS process using a minimum feature size of 6 µm. A single layer of metal was used to interconnect the approximately 6000 transistors in the design (the higher resistance polysilicon layer required to implement transistor gates was also used for some interconnects). The die size was approximately 20 mm². Integrated circuit of Atmel Diopsis 740 System on Chip showing memory blocks, logic and input/output pads around the periphery Microchips with a transparent window, showing the integrated circuit inside. ... nMOS logic uses n-type metal-oxide-semiconductor field effect transistors (MOSFETs) to implement logic gates and other digital circuits. ... An electrical connection between discrete points allows the flow of electrons, (current). ... Electrical resistance is a measure of the degree to which an electrical component opposes the passage of current. ... Polycrystalline silicon or polysilicon or poly-Si or simply poly (in context) is a material consisting of multiple small silicon crystals, and has long been used as the conducting gate material in MOSFET and CMOS processing technologies. ... Die preparation is a step of semiconductor device fabrication during which a wafer is prepared for IC packaging and IC testing. ...


The industrial impact

Applications and successors

The 8080 was used in many early microcomputers, such as the MITS Altair 8800 and IMSAI 8080, forming the basis for machines running the CP/M operating system (the later, fully compatible and more capable, Zilog Z80 processor would capitalize on this, with Z80 & CP/M becoming the dominant CPU & OS combination of the period much like x86 & MS-DOS for the PC a decade later). The first single-board microcomputer was based on the 8080. The company Landis & Gyr used it on its electrical metering data acquisition equipment, the Datagyr FAB during the early eighties. The current version of the article or section is written like a magazine article instead of the formal tone expected of an encyclopedia. ... The IMSAI 8080 microcomputer, manufactured by IMS Associates, Inc. ... CP/M was an operating system originally created for Intel 8080/85 based microcomputers by Gary Kildall of Digital Research, Inc. ... One of the first Z80 microprocessors manufactured; the date stamp is from June 1976. ... x86 or 80x86 is the generic name of a microprocessor architecture first developed and manufactured by Intel. ... Microsofts disk operating system, MS-DOS, was Microsofts implementation of DOS, which was the first popular operating system for the IBM PC, and until recently, was widely used on the PC compatible platform. ... Single-board computers (SBCs) are complete computers built on a single circuit board. ... Landis & Gyr is a Swiss company formed in 1896, with headquarters in Zug. ...


Shortly after the launch of the 8080, the Motorola 6800 competing design was introduced, and after that, the MOS Technology 6502 variation of the 6800. Zilog introduced the Z80, which had a compatible machine-language instruction set and initially used the same assembly language as the 8080, but for legal reasons, Zilog developed a syntactically-different alternative assembly language for the Z80. At Intel, the 8080 was followed by the compatible and electrically more elegant 8085, and later by the assembly language compatible 16-bit 8086 and then the 8/16-bit 8088, which was selected by IBM for its new PC to be launched in 1981. The 8080, via its ISA, thus made a lasting impact on computer history. Motorola 6800 Microprocessor The 6800 is a microprocessor produced by Motorola and released shortly after the Intel 8080 in 1975. ... The MOS Technology 6502 is an 8-bit microprocessor that was designed by Chuck Peddle for MOS Technology in 1975. ... Zilog, often seen as ZiLOG, is a manufacturer of 8-bit, 16-bit, 24-bit, and 32-bit CPUs, and is most famous for its Intel 8080-compatible Z80 series. ... One of the first Z80 microprocessors manufactured; the date stamp is from June 1976. ... The Intel 8085 was an 8-bit microprocessor made by Intel in the mid-1970s. ... The intels 8086 was the first one launched in 1978. ... An Intel 8088 microprocessor The Intel 8088 is an Intel microprocessor based on the 8086, with 16-bit registers and an 8-bit external data bus. ... International Business Machines Corporation (known as IBM or Big Blue; NYSE: IBM) is a multinational computer technology and consulting corporation headquartered in Armonk, New York, USA. The company is one of the few information technology companies with a continuous history dating back to the 19th century. ... IBM PC (IBM 5150) with keyboard and green screen monochrome monitor (IBM 5151), running MS-DOS 5. ... An instruction set, or instruction set architecture (ISA), describes the aspects of a computer architecture visible to a programmer, including the native datatypes, instructions, registers, addressing modes, memory architecture, interrupt and exception handling, and external I/O (if any). ...


The Soviet Union manufactured a complete 8080 analog named KP580ИK80 (later marked as KP580BM80), where even the pins were placed identically. This processor was the base of the Radio86RK (Радио 86РК in Russian), probably the most popular amateur single-board computer in the Soviet Union. Radio86RK's predecessor was the Micro-80 (Микро-80 in Russian), and its successor the Orion-128 (Орион-128 in Russian) which had a graphical display. Both were built on the KP580 processor. According to some sources, the Soviet analog had two undocumented instructions, specific to itself; however, these were not widely known.


Industry change

The 8080 also changed how computers were created. When the 8080 was introduced, computer systems were usually created by computer manufacturers such as Digital Equipment Corporation, Hewlett Packard, or IBM. A manufacturer would produce the entire computer, including processor, terminals, and system software such as compilers and operating system. The 8080 was actually designed for just about any application except a complete computer system. Hewlett Packard developed the HP 2640 series of smart terminals around the 8080. The HP 2647 was a terminal which ran BASIC on the 8080. Microsoft would create the first popular programming language for the 8080, and would later acquire DOS for the IBM-PC. The DEC logo Digital Equipment Corporation was a pioneering American company in the computer industry. ... The Hewlett-Packard Company (NYSE: HPQ), commonly known as HP, is currently the worlds largest information technology corporation (by revenue) and is known worldwide for its printers, personal computers and related services. ... International Business Machines Corporation (known as IBM or Big Blue; NYSE: IBM) is a multinational computer technology and consulting corporation headquartered in Armonk, New York, USA. The company is one of the few information technology companies with a continuous history dating back to the 19th century. ... The HP2640 and other HP264X models were block-mode smart and intelligent terminals produced by Hewlett Packard using the new 8080 processor. ... HP 2640 Terminal The HP2640 and other HP264X models were block-mode smart and intelligent ASCII standard serial terminals produced by Hewlett Packard using the Intel 8008 and 8080 microprocessors. ... BASIC (Beginners All-purpose Symbolic Instruction Code) is a family of high-level programming languages. ... Microsoft Corporation, (NASDAQ: MSFT, HKSE: 4338) is a multinational computer technology corporation with global annual revenue of US$44. ... Instructions on how to use the directory command. ... The IBM PC (Personal Computer), was the original version and progenitor of the IBM PC compatible hardware platform. ...


As the 8080 evolved into the largely compatible x86 family, PCs evolved into workstations and servers of 16, 32 and 64 bits, with advanced memory protection, segmentation, and multiprocessing features, blurring the difference between small and large computers (the 80286 and 80386's protected mode were important in doing so). The size of chips has grown so that the size and power of large x86 chips is not much different from high end architecture chips, and a common strategy to produce a very large computer is to network many x86 processors. The Intel 80286 is an x86-family 16-bit microprocessor that was introduced by Intel on February 1, 1982. ... The Intel 80386 is a microprocessor which was used as the central processing unit (CPU) of many personal computers from 1986 until 1994 and later. ... Protected mode is an operational mode of x86-compatible CPUs of the 80286 series or later. ...


The basic architecture of the 8080 and its successors has replaced many proprietary midrange and mainframe computers, and withstood challenges of technologies such as RISC. Most computer manufacturers have abandoned producing their own processors below the highest performance points. Though x86 may not be the most elegant, or theoretically most efficient design, the sheer market force of so many dollars going into refining a design has made the x86 family today, and will remain for some time, the dominant processor architecture, even bypassing Intel's attempts to replace it with incompatible architectures such as the iAPX 432 and Itanium. Reduced Instruction Set Computer (RISC), is a microprocessor CPU design philosophy that favors a smaller and simpler set of instructions that all take about the same amount of time to execute. ... The Intel iAPX 432 was Intels first 32-bit microprocessor design, introduced in 1981 as a set of three integrated circuits. ... Itanium 2 logo Old Itanium logo The Itanium is an IA-64 microprocessor developed jointly by Hewlett-Packard and Intel. ...


History

Federico Faggin was the originator of the 8080 architecture in early 1972, proposed it to Intel's management and pushed for its implementation. He finally got the permission to develop it six months later. Faggin hired Masatoshi Shima from Japan who did the detailed design under his direction. Stan Mazor contributed a couple of instructions to the instruction set. Federico Faggin (born 1 December 1941) is a physicist and electrical engineer considered to be one of the inventors of the microprocessor. ... Federico Faggin (born 1 December 1941) is a physicist and electrical engineer considered to be one of the inventors of the microprocessor. ... Masatoshi Shima (嶋正利 Shima Masatoshi, born on August 22, 1943 in Shizuoka, Japan) was at least partly responsible for the design of the worlds first microprocessor, the Intel 4004. ...


Patent

US # 4,010,449. March 1, 1977. Federico Faggin, Masatoshi Shima, Stanley Mazor: "MOS computer employing a plurality of separate chips." Federico Faggin (born 1 December 1941) is a physicist and electrical engineer considered to be one of the inventors of the microprocessor. ... Masatoshi Shima (嶋正利 Shima Masatoshi, born on August 22, 1943 in Shizuoka, Japan) was at least partly responsible for the design of the worlds first microprocessor, the Intel 4004. ...


Trivia

  • Asteroid (8080) Intel reflects the name of this processor. [1]

253 Mathilde, a C-type asteroid. ...

See also

CP/M was an operating system originally created for Intel 8080/85 based microcomputers by Gary Kildall of Digital Research, Inc. ...

External links

This article was originally based on material from the Free On-line Dictionary of Computing, which is licensed under the GFDL. The Free On-line Dictionary of Computing (FOLDOC) is an online, searchable encyclopedic dictionary of computing subjects. ... Bold text // “GFDL” redirects here. ...


  Results from FactBites:
 
The Intel 8080 (251 words)
The 8080 was created by the Intel with Federico Faggin as the lead designer (his last chip before he left and started Zilog).
The 8080 was released in March of 1974.
The 8080 family is also referred to as the MCS-80.
Intel 8080 (178 words)
The Intel 8080 was an early CPU designed and manufactured by Intel.
The Intel 8080 successor to the Intel 8008 (with which it was Assembly language source compatible[?]).
The 8080 (permitted by its large 40 pin DIP packaging) had a 16-bit address bus[?] and an 8-bit data bus.
  More results at FactBites »

 
 

COMMENTARY     


Share your thoughts, questions and commentary here
Your name
Your comments

Want to know more?
Search encyclopedia, statistics and forums:

 


Press Releases |  Feeds | Contact
The Wikipedia article included on this page is licensed under the GFDL.
Images may be subject to relevant owners' copyright.
All other elements are (c) copyright NationMaster.com 2003-5. All Rights Reserved.
Usage implies agreement with terms, 1022, m