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In computer architecture, 1-bit integers or other data units are those that are 1 bit (1/8 octet) wide. Also, 1-bit central processing unit (CPU) and arithmetic logic unit (ALU) architectures are those that are based on registers of that size.
There are no computers or microcontrollers of any kind that are exclusively 1-bit for all registers and address buses. A 1-bit register can only store two different values. This is very restrictive and therefore not enough for a program counter which, on modern systems, is implemented in an on-chip register, but is not implemented on-chip in some 1-bit systems. Opcodes for at least one 1-bit processor architecture were 4-bit and the address bus was 8-bit.
While 1-bit computing is rarely used on its own today, 1-bit serial communication is still used in modern computers, even on machines with large internal buses.
The first carbon nanotube computer from 2013 is a 1-bit one-instruction set computer (and has only 178 transistors; though it has only one instruction, it can emulate 20 MIPS instructions).[1]
1-bit
A serial computer processes data a single bit at a time. For example, the PDP-8/S was a 12-bit computer using a 1-bit ALU, processing the 12 bits serially.[2]
An example of a 1-bit computer built from discrete logic SSI chips is the Wang 500 (1970/1971) calculator[3][4] as well as the Wang 1200 (1971/1972)[5] word processor series developed by Wang Laboratories.
Other examples of 1-bit architectures are programmable logic controllers (PLCs), such as the 1969 PDP-14.[6] These were often programmed in ladder logic or in instruction list (IL). An example of such a 1-bit architecture that was marketed as a CPU is the Motorola MC14500B Industrial Control Unit (ICU),[7][8] introduced in 1977 and manufactured at least up into the mid 1990s.[8] Its manual states:
See also
- Bit-serial architecture
- Bit banging
- Bit slicing
- Turing machine
- Enhanced Serial Peripheral Interface (eSPI) allows 1-bit communication
References
- ↑ Courtland, Rachel (2013-09-25). "First Computer Made From Carbon Nanotubes Debuts - The modest 1-bit, 1 kHz machine could usher in a new post-silicon era". IEEE Spectrum: Technology, Engineering, and Science News. Archived from the original on 2022-06-15. Retrieved 2021-04-18.
- ↑ "III. System Logic - 3.4. Control Circuits - 3.4.1 Adder". PDP-8/S Maintenance Manual (PDF) (4th printing ed.). Maynard, Massachusetts, US: Digital Equipment Corporation. August 1969 [October 1967]. pp. 3-14 – 3-15. F-87S. Archived (PDF) from the original on 2021-10-23. Retrieved 2022-06-15. (191 pages)
- ↑ Wasserman, Katie (March 2006) [January 2004]. "LED calculators rule her house". Computer Collector Newsletter / Technology Rewind (Interview). Interviewed by Koblentz, Evan. Retrieved 2017-05-20.
Probably my most favorite is the Wang 500. It's got several unique things about it: a very unusual ROM memory made of hundreds of long enamel-coated wires wrapped around iron cores; a super-fast single-bit CPU built out of SSI logic chips; and of course tons of really cool-looking colorful keys.
{{cite interview}}: CS1 maint: deprecated archival service (link) - ↑ Product Service - Schematic manual (PDF). Wang Laboratories, Inc. 1974. 03-0019-0. Archived (PDF) from the original on 2017-05-20. Retrieved 2017-05-20.
- ↑ Battle, Jim (2010-03-07). "Wang 1200 - Wang WP History". Archived from the original on 2017-05-21. Retrieved 2017-05-21.
- ↑ "DEC PDP-14 Industrial Controller".
- 1 2 3 Gregory, Vern; Dellande, Brian; DiSilvestro, Ray; Malarkey, Terry; Smith, Phil; Hadley, Mike (1977). Motorola MC14500B Industrial Control Unit Handbook - Theory and Operation of a CMOS one-bit processor compatible with B series CMOS devices (PDF). Motorola Semiconductor Products Inc. 33-B78/8.0. Archived (PDF) from the original on 2022-04-01. Retrieved 2017-05-20. (NB. Also available in German language under the title "Motorola MC14500B Industrial Control Unit Handbuch - Theorie und Anwendung eines Ein-Bit-CMOS-Prozessors".)
- 1 2 "Industrial Control Unit MC14500B". Motorola CMOS Logic Data (PDF). Semiconductor Technical Data (revision 3 ed.). Motorola. 1995. pp. 306–313. Archived (PDF) from the original on 2017-05-20. Retrieved 2012-08-01.
- ↑ Ludwig, Volker; Paschenda, Klaus; Schepers, Heinz; Terglane, Hermann-Josef; Grannemann, Klaus; John, Burkhard; Komar, Hermann; Meinersen, Ludwig (1986). Fast alles über den WDR-1-Bit-Computer (PDF) (in German). Neuss & Recklinghausen, Germany: DATANorf. Archived (PDF) from the original on 2017-05-20. Retrieved 2017-05-20.
Further reading
- Mueller, Dieter (2005) [2004]. "The famous/infamous MC14500". Archived from the original on 2017-08-03. Retrieved 2018-07-18.
- Mueller, Dieter (2008). "MC14500 and arithmetic". Archived from the original on 2017-05-20. Retrieved 2018-07-18.
- Mueller, Dieter (2008). "A MC14500 modification". Archived from the original on 2017-03-20. Retrieved 2018-07-18.
External links
- Schembri, Thierry; Bizoirre, Sylvain; Boisseau, Olivier; Chauvaud, Pierre-Emmanuel. "WDR-1-Bit Computer". OLD-COMPUTERS.COM. Archived from the original on 2017-05-20. Retrieved 2017-05-20.