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 aspect of a computer control unit (CCU). By using a bit slicing technique, 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. One major problem with this modular technique was it required a larger amount of ICs to implement what could be done on a single CPU IC. The Am2901 chip was the arithmetic-logic unit (ALU), and the "core" of the series. It could count using 4 bits and implement binary operations as well as various bit-shifting operations.
Computers made with Am2900-family chips 
There are probably many more, but here are some known machines using these parts:
- The Itek Advanced Technology Airborne Computer (ATAC) used on the Galileo 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 2901 chips.
- Data General Nova 4, which obtained 16-bit word width using four Am2901 ALUs in parallel; one of the boards had 15 Am2901 ALUs on it.
- Digital Equipment Corporation (DEC) PDP-11 models PDP-11/23, PDP-11/34, and PDP-11/44 floating-point options (FPF11, FP11-A and FP11-F, respectively)
- The Xerox Dandelion, the machine used in the Xerox Star and Xerox 1108 Lisp machine
- Several models of the GEC 4000 series 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 model
- The UCSD Pascal P-machine processor designed at NCR by Joel McCormack
- A number of MAI Basic Four machines
- The Tektronix 4052 graphics system computer
- The SM-1420, Soviet clone of PDP-11, used Soviet clone of AM2901 perhaps also used in others.
- The Lilith computer designed at ETH Zürich by Niklaus Wirth
- Atari's vector graphics arcade machines Tempest, Battlezone, and Red Baron each used 4 Am2901 ICs in their "math box" auxiliary circuit boards.
- Simulation Excel (Sim-X), Oslo, Norway: Typographical workstation / typesetter; one of its four processors was a 16-bit microcoded calculation and transformation engine built from four 2901 slices and one 2910 address sequencer. The Sim-X machine used a 16-bit integer multiplier to optimize graphical transformations. The machine debuted in 1983 and the company shut down in 1987.
- 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 Teleperm and S5 PLCs used for industrial control were built using the 2900 series.
- AT&T 3B20D Processor
- Metheus / Barco Omega 400 and 500 Series graphics systems; four Am2901 chips (and eight microcode PROMs) were used to perform graphics operations on this 1982 display processor.
Members of the Am2900 family 
The Am2900 Family Data Book lists:
- Am2901 – 4-bit bit-slice ALU (1975)
- Am2902 – Look-Ahead Carry Generator
- Am2903 – 4-bit-slice ALU, with hardware multiply
- 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 – 12-bit address sequencer
- Am2911 – 4-bit-slice address sequencer
- Am2912 – Bus Transceiver
- Am2913 – Priority Interrupt 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, Quad D Register
- Am2919 – Instruction Register, Quad Register
- Am2920 – Octal D-Type Flip-Flop
- Am2921 – 1-to-8 Decoder
- Am2922 – 8-Input Multiplexer (MUX)
- Am2923 – 8-Input MUX
- Am2924 – 3-Line to 8-Line Decoder
- Am2925 – System Clock Generator and Driver
- Am2926 – Schottky transistor 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 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 Buss Buffers
- Am2964 – Dynamic Memory Controller
- Am2965/Am2966 – Octal Dynamic Memory Driver, Image
Many of these chips also have 7400 series numbers such as the 74F2960 / Am2960.
See also 
- "Computers in Spaceflight: The NASA Experience" - Chapter Six - - Distributed Computing On Board Voyager and Galileo -
- "Data General NOVA4/X recovered from Bakersfield". January 17, 2005. Archived from the original on 17 July 2011. Retrieved July 11, 2011.
- "Photo of DEC11-34". CPU museum web site. Archived from the original on 8 July 2011. Retrieved July 11, 2011.
- John Holden. "Production PDP-11 Models". University of Sydney School of Psychology. Archived from the original on 25 July 2011. Retrieved July 11, 2011.
- Nathan Lineback. "Xerox Star". Nathan's Toasty Technology page. Archived from the original on 18 July 2011. Retrieved July 11, 2011.
- Andrew Gabriel (1997). "GEC 4000 series processors". Archived from the original on 19 July 2011. Retrieved July 11, 2011.
- Klaus Michael Indlekofer (November 11, 2002). "Computer Architectures". K.M.I. - the site. Archived from the original on 17 July 2011. Retrieved July 11, 2011.
- "Field Information Bulletin 113". March 28, 1988. Archived from the original on 7 July 2011. Retrieved July 11, 2011.
- Справочник по электронной вычислительной технике (in Russian). 1993. p. 124. ISBN 5-217-02090-3.
- "Part VII: Advanced Micro Devices Am2901, a few bits at a time". Great Microprocessors of the Past and Present. Russian Supercomputer Software Department. 1998. Archived from the original on June 16, 2009. Retrieved July 11, 2011.
- Kari Johnson (1983). "An IEEE Floating Point Arithmetic Implementation". IEEE Symposium on Computer Arithmetic: 130–135.
- "3B20D Central Processing Unit". The Bell System Technical Journal. 1.1.2 Data manipulation unit 62 (1): 193. January 1983.
- "The Am2900 Family Data Book with Related Support Circuits". AM-PUB003. Advanced Micro Devices. 1979. Archived from the original on 16 July 2011. Retrieved July 11, 2011.
|Wikimedia Commons has media related to: Am29xx|
- 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
- Am29C300/29300 Data Book Bitsavers' PDF document archive
- CPU-World photos of 2900 Family ICs
- Bit-Slice Design: micro-controllers and ALUs. an Introduction to the Am2900 Family
- Bit-Sliced Microprocessor of the Am2900 Family