Programmable logic device

A programmable logic device is an electronic component used to build reconfigurable digital circuits. Unlike integrated circuits which consist of logic gates and have a fixed function, a PLD has an undefined function at the time of manufacture. Before the PLD can be used in a circuit it must be programmed by using a specialized program. In 1969, Motorola offered the XC157, a mask-programmed gate array with 12 gates and 30 uncommitted input/output pins. In 1970, Texas Instruments developed a mask-programmable IC based on the IBM read-only associative memory or ROAM; this device, the TMS2000, was programmed by altering the metal layer during the production of the IC. The TMS2000 had 18 outputs with 8 JK flip flop for memory. TI coined the term Programmable Logic Array for this device. In 1971, General Electric Company was developing a programmable logic device based on the new Programmable Read-Only Memory technology; this experimental device improved on IBM's ROAM by allowing multilevel logic. Intel had just introduced the floating-gate UV erasable PROM so the researcher at GE incorporated that technology.

The GE device was the first erasable PLD developed, predating the Altera EPLD by over a decade. GE obtained several early patents on programmable logic devices. In 1973 National Semiconductor introduced a mask-programmable PLA device with 14 inputs and 8 outputs with no memory registers; this was more popular than the TI part but cost of making the metal mask limited its use. The device is significant because it was the basis for the field programmable logic array produced by Signetics in 1975, the 82S100. In 1974 GE entered into an agreement with Monolithic Memories to develop a mask–programmable logic device incorporating the GE innovations; the device was named the'Programmable Associative Logic Array' or PALA. The MMI 5760 was completed in 1976 and could implement multilevel or sequential circuits of over 100 gates; the device was supported by a GE design environment where Boolean equations would be converted to mask patterns for configuring the device. The part was never brought to market.

In 1970, Texas Instruments developed a mask-programmable IC based on the IBM read-only associative memory or ROAM. This device, the TMS2000, was programmed by altering the metal layer during the production of the IC; the TMS2000 had 18 outputs with 8 JK flip-flops for memory. TI coined the term programmable logic array for this device. A programmable logic array has a programmable AND gate array, which links to a programmable OR gate array, which can be conditionally complemented to produce an output. PAL devices have arrays of transistor cells arranged in a "fixed-OR, programmable-AND" plane used to implement "sum-of-products" binary logic equations for each of the outputs in terms of the inputs and either synchronous or asynchronous feedback from the outputs. MMI introduced a breakthrough device in 1978, the programmable array logic or PAL; the architecture was simpler than that of Signetics FPLA because it omitted the programmable OR array. This made the parts faster and cheaper, they were available in 20 pin 300 mil DIP packages.

The PAL Handbook demystified the design process. The PALASM design software converted the engineers' Boolean equations into the fuse pattern required to program the part; the PAL devices were soon second-sourced by National Semiconductor, Texas Instruments and AMD. After MMI succeeded with the 20-pin PAL parts, AMD introduced the 24-pin 22V10 PAL with additional features. After buying out MMI, AMD spun off a consolidated operation as Vantis, that business was acquired by Lattice Semiconductor in 1999. An improvement on the PAL was the generic array logic device, or GAL, invented by Lattice Semiconductor in 1985; this device can be erased and reprogrammed. The GAL is useful in the prototyping stage of a design, when any bugs in the logic can be corrected by reprogramming. GALs are programmed and reprogrammed using a PAL programmer, or by using the in-circuit programming technique on supporting chips. Lattice GALs combine CMOS and electrically erasable floating gate technology for a high-speed, low-power logic device.

A similar device called. PALs and GALs are equivalent to a few hundred logic gates. For bigger logic circuits, complex PLDs or CPLDs can be used; these contain the equivalent of several PALs linked by programmable interconnections, all in one integrated circuit. CPLDs can replace thousands, or hundreds of thousands, of logic gates; some CPLDs are programmed using a PAL programmer, but this method becomes inconvenient for devices with hundreds of pins. A second method of programming is to solder the device to its printed circuit board feed it with a serial data stream from a personal computer; the CPLD contains a circuit that decodes the data stream and configures the CPLD to perform its specified logic function. Some manufacturers use JTAG to program CPLDs in-circuit from. JAM files. While PALs were being developed into GALs and CPLDs, a separate stream of development was happening; this type of device is based on gate array technology and is called the field-programmable gate array. Early examples of FPGAs are the 82s100 array, 82S105 sequencer, by Signetics, introduced in the late 1970s.

The 82S100 was an array of AND terms. The 82S105 had flip flop functions. (Anmerk: 82S100 und ähnl ICs from Signet

Ringstead and Addington railway station

Ringstead and Addington railway station was a railway station serving Great and Little Addington and Ringstead in Northamptonshire on the former Northampton and Peterborough Railway which connected Peterborough and Northampton. In 1846 the line, along with the London and Birmingham, became part of the London and North Western Railway. At grouping in 1923 it became part of the London Scottish Railway, it was notable that the approach from Addington was across stepping stones made from former railway sleeper blocks. This still remains; the service was from Peterborough to Northampton via Wellingborough. The station closed in 1964 to passengers. Former Services Subterranea Britannica

Brian Catling

Brian Catling is an English sculptor, novelist, film maker and performance artist. He was educated at the Royal College of Art, he now holds the post of Professor of Fine Art at The Ruskin School of Drawing and Fine Art, Oxford and is a fellow of Linacre College. He has been exhibiting his work internationally since the 1970s; some of his most notable works and performances include: Quill Two at Matt's Gallery, Dilston Grove in 2011, Antix at Matt's Gallery in 2006, a commissioned memorial to the Site of Execution, Tower of London in 2007, Vanished! A Video Seance made with screenwriter Tony Grisoni in 1999 and Cyclops at South London Gallery 1996. In 2001 he co founded the international performance collective WitW; as a writer he has published poetic works, including one compendium, A Court of Miracles, in 2009. His first prose book Bobby Awl was published in 2007, he is writing novels and has completed The Vorrh trilogy. The first title of The Vorrh trilogy was published in 2012 and features a foreword by acclaimed comic-book writer Alan Moore.

Taking inspiration from the imaginary forest of the same name in Raymond Roussel's Impressions of Africa the Vorrh is the backdrop to an epic fantasy/surrealist narrative led by hunter Tsungali and the Cyclops, Ishmael. Appearing in The Vorrh are real-life figures Eadweard Muybridge and Raymond Roussel; the Vorrh The Erstwhile The Cloven 2011 Quill Two Matt's Gallery at Dilston Grove 2010 Bluecoat Gallery Liverpool bienalle 2008 Ingleby Gallery, Edinburgh. Scotland 2006 Antix. Matt's Gallery. London. 16 night Performance installation 2002 Antic Video installation. Trans-Art Gallery Trondheim. Norway 2002 Buhl Cyclops. Video installation. AKW. Stadt Buhl. Germany 2000 Man in the Moon. Galleri e.s. Bergen 1999 Were: The Chamber works, ICA, London 1998 Were, durational performance, Matt's Gallery, London 1997 Cyclops, Project Gallery, Leipzig 1997 Country of the Blind, drawings & video, The Economist, London 1997 Nordic Cyclops, Museet for Samtidskunst, Oslo 1996 Cyclops, South London Gallery 1995 Cyclops, Galerie Satellite, Paris 1994 The Blindings, Serpentine Gallery, London 1993 Ten Gallery, Japan 1993 La Bas, Galerie Satellite, Paris 1991 At The Lighthouse, Matt's Gallery, London 1989 Museum of Modern Art, Oxford 1988 Atrium, Neuw Gallery, Sammalung Ludwig, Germany 1987 White Breath / Red Heart, Hordaland Kunstnercentrum, Norway 1987 Lair, Matt's Gallery, London 1986 On Touching And Haunting A Noble Silent Room, Leifsgade 22, Copenhagen A Court of Miracles Thyhand Large Ghost Late Harping The Blindings The Stumbling Block, Its Index Bobby Awl The Vorrh The Erstwhile The Cloven Earwig Twentieth- Century British and Irish Poetry Vanishing Points Pittancer Conductors of Chaos The New British Poetry Future Exiles Official website Official website of WitW 1 painting by or after Brian Catling at the Art UK site Interview with Brian Catling Profile on Royal Academy of Arts Collections