Am2900 is a family of

integrated circuit An integrated circuit (IC), also known as a microchip or simply chip, is a set of electronic circuits, consisting of various electronic components (such as transistors, resistors, and capacitors) and their interconnections. These components a ...

s (ICs) created in 1975 by

Advanced Micro Devices Advanced Micro Devices, Inc. (AMD) is an American multinational corporation and technology company headquartered in Santa Clara, California and maintains significant operations in Austin, Texas. AMD is a Information technology, hardware and F ...

(AMD). They were constructed with bipolar devices, in a

bit-slice Bit slicing is a technique for constructing a processor from modules of processors of smaller bit width, for the purpose of increasing the word length; in theory to make an arbitrary ''n''-bit central processing unit (CPU). Each of these c ...

topology, and were designed to be used as modular components each representing a different aspect of a computer

control unit The control unit (CU) is a component of a computer's central processing unit (CPU) that directs the operation of the processor. A CU typically uses a binary decoder to convert coded instructions into timing and control signals that direct the op ...

(CCU). By using the

bit slicing Bit slicing is a technique for constructing a processor from modules of processors of smaller bit width, for the purpose of increasing the word length; in theory to make an arbitrary ''n''-bit central processing unit (CPU). Each of these c ...

technique, the Am2900 family was able to implement a CCU with data, addresses, and instructions to be any multiple of 4 bits by multiplying the number of ICs. This requires more ICs to implement than what could be done on a single CPU IC, but at the time, the TTL Am2900 chips ran at 2040Mhz, which was much faster than the 23Mhz CMOS/NMOS microprocessors of the era such as the

Intel 8085 The Intel 8085 ("''eighty-eighty-five''") is an 8-bit microprocessor produced by Intel and introduced in March 1976. It is software-binary-code compatibility, binary compatible with the more-famous Intel 8080. It is the last 8-bit microprocesso ...

. 8085 emulators were implemented around two Am2900 chips which ran 5 to 10 times faster than the 8085-based designs they replaced. The Am2901 chip included an

arithmetic logic unit In computing, an arithmetic logic unit (ALU) is a Combinational logic, combinational digital circuit that performs arithmetic and bitwise operations on integer binary numbers. This is in contrast to a floating-point unit (FPU), which operates on ...

(ALU) and 16 4-bit

processor register A processor register is a quickly accessible location available to a computer's processor. Registers usually consist of a small amount of fast storage, although some registers have specific hardware functions, and may be read-only or write-onl ...

slices, and was the "core" of the series. It could count using 4 bits and implement binary operations as well as various bit-shifting operations. The Am2909 was a 4-bit-slice address sequencer that could generate 4-bit addresses on a single chip, and by using n of them, it was able to generate 4n-bit addresses. It had a stack that could store a microprogram counter up to 4 nest levels, as well as a stack pointer. The 2901 and some other chips in the family were

second source In the electronics industry, a second source is a company that is licensed to manufacture and sell components originally designed by another company (the first source). It is common for engineers and purchasers to seek components that are availab ...

d by an unusually large number of other manufacturers, starting with Motorola and then Raytheon both in 1975 and also Cypress Semiconductor, National Semiconductor, NEC, Thomson, and Signetics. In the Soviet Union and later Russia the Am2900 family was manufactured as the 1804 series (with e.g. the Am2901

designated Designation (from Latin ''designatio'') is the process of determining an incumbent's successor. A candidate that won an election, for example, is the ''designated'' holder of the office the candidate has been elected to, up until the candidate's ...

as KR1804VS1 / ) which was known to be in production in 2016.

Computers made with Am2900-family chips

There are probably many more, but here are some known machines using these parts: * The

Apollo Computer Apollo Computer Inc. was an American technology corporation headquartered and founded in Chelmsford, Massachusetts. It was founded in 1980 by William Poduska (a founder of Prime Computer) and others. Apollo Computer developed and produced Apoll ...

Tern family: DN460, DN660 and DSP160. All used the same system board emulating the

Motorola 68010 The Motorola MC68010 and Motorola MC68012 are 16/32-bit microprocessor, microprocessors from Motorola, released in 1982 as successors to the Motorola 68000. The 68010 and 68012 added virtualization features, optimized loops and fixed several sma ...

instruction set. * The

Itek Itek Corporation was a United States defense contractor that initially specialized in camera systems for spy satellites and various other reconnaissance systems. In the early 1960s they built a conglomerate in a fashion similar to LTV or Litt ...

Advanced Technology Airborne Computer The Advanced Technology Airborne Computer (ATAC) was a product of Itek (a division of Litton Industries), used on US naval aircraft, and the NASA Galileo (spacecraft). The ATAC was built using AMD 2901 4-bit processors and had a basic cycle time ...

(ATAC) used on the

Galileo Galileo di Vincenzo Bonaiuti de' Galilei (15 February 1564 – 8 January 1642), commonly referred to as Galileo Galilei ( , , ) or mononymously as Galileo, was an Italian astronomer, physicist and engineer, sometimes described as a poly ...

Attitude and Articulation Control Computer System and some Navy aircraft had a 16-register, 16-bit word width assembled from 4-bit-wide 2900 series processors. Four special instructions were added to the Galileo version of the ATAC, and later some chips were replaced with

radiation-hardened Radiation hardening is the process of making electronic components and circuits resistant to damage or malfunction caused by high levels of ionizing radiation (particle radiation and high-energy electromagnetic radiation), especially for environm ...

2901 chips. *

Data General Nova The Nova is a series of 16-bit computing, 16-bit minicomputers released by the American company Data General. The Nova family was very popular in the 1970s and ultimately sold tens of thousands of units. The first model, known simply as "Nov ...

4, which obtained 16-bit word width using four Am2901 ALUs in parallel. The floating point board has 15 Am2901 ALUs on it. *

Digital Equipment Corporation Digital Equipment Corporation (DEC ), using the trademark Digital, was a major American company in the computer industry from the 1960s to the 1990s. The company was co-founded by Ken Olsen and Harlan Anderson in 1957. Olsen was president until ...

(DEC)

PDP-11 The PDP–11 is a series of 16-bit minicomputers originally sold by Digital Equipment Corporation (DEC) from 1970 into the late 1990s, one of a set of products in the Programmed Data Processor (PDP) series. In total, around 600,000 PDP-11s of a ...

models PDP-11/34 FP11-A and PDP-11/44 FP11-F floating-point options. * The DEC VAX 11/730, which used eight Am2901s in the CPU. *

Hewlett-Packard The Hewlett-Packard Company, commonly shortened to Hewlett-Packard ( ) or HP, was an American multinational information technology company. It was founded by Bill Hewlett and David Packard in 1939 in a one-car garage in Palo Alto, California ...

1000 A-series model A600 used four Am2901 ALUs for its 16-bit processor * The Xerox Dandelion, the machine used in the

Xerox Star The Xerox Star workstation, officially named Xerox Star 8010 Information System, is the first commercial personal computer to incorporate technologies that have since become standard in personal computers, including a bitmapped display, a window- ...

and Xerox 1108 Lisp machine. * Several models of the

GEC 4000 series The GEC 4000 was a series of 16-bit, 16/32-bit minicomputers produced by GEC Computers, GEC Computers Ltd in the United Kingdom during the 1970s, 1980s and early 1990s. History GEC Computers was formed in 1968 as a business unit of the Gen ...

minicomputers: 4060, 4150, 4160 (four Am2901 each, 16-bit ALU), and 4090 and all 418x and 419x systems (eighteen Am2901 each, 32-bit integer ALU or 8-bit exponent, 64-bit Double Precision floating point ALU). * The DEC KS10

PDP-10 Digital Equipment Corporation (DEC)'s PDP-10, later marketed as the DECsystem-10, is a mainframe computer family manufactured beginning in 1966 and discontinued in 1983. 1970s models and beyond were marketed under the DECsystem-10 name, especi ...

model. * The

UCSD Pascal UCSD Pascal is a Pascal programming language system that runs on the UCSD p-System, a portable, highly machine-independent operating system. UCSD Pascal was first released in 1977. It was developed at the University of California, San Diego (UC ...

P-machine processor designed at NCR by

Joel McCormack Joel McCormack is an American computer scientist who designed the NCR Corporation version of the p-code machine, which is a kind of stack machine popular in the 1970s as the preferred way to implement new computing architectures and languages su ...

. * A number of

MAI Basic Four Basic/Four is a variety of Business Basic which originally ran on computers of the same name introduced in 1971. The company that produced the system, Management Assistance, Inc., was later known as Basic/Four Corporation, MAI Basic Four, Inc., and ...

machines. * The

Tektronix 4052 The Tektronix 4050 is a series of three desktop computers produced by Tektronix in the late 1970s through the early 1980s. The display technology is similar to the Tektronix 4010 terminal, using a storage tube display to avoid the need for video ra ...

graphics system computer. * The

SM-1420 The SM-1420 (CM-1420) is a 16 bit DEC PDP-11/45 minicomputer clone, and the successor to SM-4 in Soviet Bloc countries. Under the direction of Minpribor it was produced in the Soviet Union and Bulgaria from 1983 onwards, and is more than twice as f ...

, Soviet clone of PDP-11, used Soviet clone of Am2901 (4 ICs in the CPU and 16 ICs in the FPU) perhaps also used in others. * The

Lilith Lilith (; ), also spelled Lilit, Lilitu, or Lilis, is a feminine figure in Mesopotamian and Jewish mythology, theorized to be the first wife of Adam and a primordial she-demon. Lilith is cited as having been "banished" from the Garden of Eden ...

computer designed at

ETH Zürich ETH Zurich (; ) is a public university in Zurich, Switzerland. Founded in 1854 with the stated mission to educate engineers and scientists, the university focuses primarily on science, technology, engineering, and mathematics. ETH Zurich ra ...

Niklaus Wirth Niklaus Emil Wirth ( IPA: ) (15 February 1934 – 1 January 2024) was a Swiss computer scientist. He designed several programming languages, including Pascal, and pioneered several classic topics in software engineering. In 1984, he won the Tu ...

. *

Atari Atari () is a brand name that has been owned by several entities since its inception in 1972. It is currently owned by French holding company Atari SA (formerly Infogrames) and its focus is on "video games, consumer hardware, licensing and bl ...

vector graphics Vector graphics are a form of computer graphics in which visual images are created directly from geometric shapes defined on a Cartesian plane, such as points, lines, curves and polygons. The associated mechanisms may include vector displ ...

arcade machines '' Battlezone'' and ''

Red Baron Red is the color at the long wavelength end of the visible spectrum of light, next to orange and opposite violet. It has a dominant wavelength of approximately 625–750 nanometres. It is a primary color in the RGB color model and a sec ...

'' both used four Am2901 ICs in their "math box" auxiliary circuit boards. '' Tempest'' had no "math box." *

raster graphics upright=1, The Smiley, smiley face in the top left corner is a raster image. When enlarged, individual pixels appear as squares. Enlarging further, each pixel can be analyzed, with their colors constructed through combination of the values for ...

arcade machine ''

I, Robot ''I, Robot'' is a fixup collection of science fiction short stories by American writer Isaac Asimov. The stories originally appeared in the American magazines '' Super Science Stories'' and ''Astounding Science Fiction'' between 1940 and 1950 ...

'', the first commercial game featuring filled polygons, included a math processor built around four Am2901 chips. *

Pixar Image Computer The Pixar Image Computer is a graphics computer originally developed by the Graphics Group, the computer division of Lucasfilm, which was later renamed Pixar. Aimed at commercial and scientific high-end visualization markets, such as medicine, ge ...

, 4 Channel Processors each with 4 Am2900's * Eventide H949 Harmonizer; four Am2901 chips (and several microcode PROMs) are used to generate addresses and generate reference voltages for the DAC system audio was not processed in the 2901 ALU section. * Many

Siemens Siemens AG ( ) is a German multinational technology conglomerate. It is focused on industrial automation, building automation, rail transport and health technology. Siemens is the largest engineering company in Europe, and holds the positi ...

Teleperm and S5 PLCs used for industrial control were built using the 2900 series. * The AT&T 3B20D used eight Am2901's in its ALU. *

Geac Computer Corporation Geac Computer Corporation, Ltd ( and ) was a producer of enterprise resource planning, performance management, and industry specific software based in Markham, Ontario. It was acquired by Golden Gate Capital's Infor unit in March 2006 for US$1 bi ...

2000, 6000, 8000, and 9000 were all based on 4 x Am2901 chips. The GEAC 9500 was based on the Am29101. The GEAC 2000 was used in pharmacies. The other models were used in library, banking, and insurance automation. The 2000 was a single processor unit. The 6000 and 8000 contained four processors, each dedicated to one of comms, disk, tape, or program processing. The 8000 had local processor memory whereas the 6000 did not. The 9000 and 9500 were AMP systems with up to 8 CPU modules. * Later iterations of the Ferranti Argus 700 e.g. the 700F and 700G, used Am2901 devices, as did as some of the A700 peripheral channel controllers for e.g. hard and floppy disc drives * The High Level Hardware Limited Orion, a user-microcodable minicomputer running Unix. * The 168/E, developed in the late 1970s at the

SLAC National Accelerator Laboratory SLAC National Accelerator Laboratory, originally named the Stanford Linear Accelerator Center, is a Federally funded research and development centers, federally funded research and development center in Menlo Park, California, Menlo Park, Ca ...

to execute a subset of the IBM 360/370 instructions. * Warrex Centurion, an 8-bit minicomputer built by Warrex Computer Corporation (later just Centurion), a Texas based company from the late 1970s to the 1980s. The Am2909 and Am2911 microprogram sequencers and the Am2901 ALU were used in the CPU6 variant. * The PerkinElmer Computer Systems Division utilized Am2900 devices in the ALU of their 3200 series supermini computers. * The second-generation 16-bit CPU of the NCR I-8250 family of accounting-computers, which replaced the earlier 605-model 4-board CPU that used discrete 7400-series TTL chips.

Members of the Am2900 family

The Am2900 Family Data Book lists: *Am2901 – 4-bit bit-slice ALU and

set (1975) *Am2902 – Look-Ahead Carry Generator *Am2903 – 4-bit-slice ALU, with

hardware multiply A binary multiplier is an electronic circuit used in digital electronics, such as a computer, to multiply two binary numbers. A variety of computer arithmetic techniques can be used to implement a digital multiplier. Most techniques involve com ...

*Am2904 – Status and Shift Control Unit *Am2905 – Bus Transceiver *Am2906 – Bus Transceiver with Parity *Am2907 – Bus Transceiver with Parity *Am2908 – Bus Transceiver with Parity *Am2909 – 4-bit-slice address sequencer *Am2910 – Microprogram Controller *Am2911 – 4-bit-slice address sequencer *Am2912 – Bus Transceiver *Am2913 – Priority

Interrupt In digital computers, an interrupt (sometimes referred to as a trap) is a request for the processor to ''interrupt'' currently executing code (when permitted), so that the event can be processed in a timely manner. If the request is accepted ...

Expander *Am2914 – Priority Interrupt Controller *Am2915 – Quad 3-State Bus Transceiver *Am2916 – Quad 3-State Bus Transceiver *Am2917 – Quad 3-State Bus Transceiver *Am2918 –

Instruction Register In computing, the instruction register (IR) or current instruction register (CIR) is the part of a CPU's control unit that holds the instruction currently being executed or decoded. In simple processors, each instruction to be executed is loaded ...

, Quad D Register *Am2919 – Instruction Register, Quad Register *Am2920 – Octal

D-Type Flip-Flop In electronics, flip-flops and latches are electronic circuit, circuits that have two stable states that can store state information – a bistable multivibrator. The circuit can be made to change state by signals applied to one or more control ...

*Am2921 – 1-to-8

Decoder Decoder may refer to: Technology * Audio decoder converts digital audio to analog form * Binary decoder, digital circuits such as 1-of-N and seven-segment decoders * Decompress (compression decoder), converts compressed data (e.g., audio/video/i ...

*Am2922 – 8-Input

Multiplexer In electronics, a multiplexer (or mux; spelled sometimes as multiplexor), also known as a data selector, is a device that selects between several Analog signal, analog or Digital signal (electronics), digital input signals and forwards the sel ...

(MUX) *Am2923 – 8-Input MUX *Am2924 – 3-Line to 8-Line

*Am2925 –

System Clock In computer science and computer programming, system time represents a computer system's notion of the passage of time. In this sense, ''time'' also includes the passing of days on the calendar. System time is measured by a ''system clock'', w ...

Generator and Driver *Am2926 – Schottky 3-State Quad Bus Driver *Am2927/Am2928 – Quad 3-State Bus Transceiver *Am2929 – Schottky 3-State Quad Bus Driver *Am2930 – Main Memory Program Control *Am2932 – Main Memory Program Control *Am2940 – Direct Memory Addressing (DMA) Generator *Am2942 – Programmable Timer/ Counter/

DMA DMA may refer to: Arts * ''DMA'' (magazine), a defunct dance music magazine * Dallas Museum of Art, in Texas, US * BT Digital Music Awards, an annual event in the UK * Danish Music Awards * Detroit Music Awards * Doctor of musical arts, a degree ...

Generator *Am2946/Am2947 – Octal 3-State Bidirectional Bus Transceiver *Am2948/Am2949 – Octal 3-State Bidirectional Bus Transceiver *Am2950/Am2951 – 8-bit Bidirectional I/O Ports *Am2954/Am2955 – Octal Registers *Am2956/Am2957 – Octal Latches *Am2958/Am2959 – Octal Buffers/Line Drivers/Line Receivers *Am2960 – Cascadable 16-bit Error Detection and Correction Unit *Am2961/Am2962 – 4-bit Error Correction Multiple Bus Buffers *Am2964 – Dynamic Memory Controller *Am2965/Am2966 – Octal Dynamic Memory Driver Many of these chips also have

7400 series The 7400 series is a popular logic family of transistor–transistor logic (TTL) integrated circuits (ICs). In 1964, Texas Instruments introduced the SN5400 series of logic chips, in a ceramic semiconductor package. A low-cost plastic package ...

numbers such as the 74F2960 / Am2960.

References

External links

Introduction to Designing with the Am2900 Family of Microprogramable Bipolar Devices Vol 1
Bitsavers' PDF document archive
Introduction to Designing with the Am2900 Family of Microprogramable Bipolar Devices Vol 2
Bitsavers' PDF document archive *
CPU-World
photos of 2900 Family ICs

an introduction to the Am2900 family

{{AMD processors

Am2900 Am2900 is a family of integrated circuits (ICs) created in 1975 by Advanced Micro Devices (AMD). They were constructed with bipolar devices, in a bit-slice topology, and were designed to be used as modular components each representing a different ...

Bit-slice chips

Computers made with Am2900-family chips

Members of the Am2900 family

See also

References

Further reading

External links