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Encyclopedia > Video Display Controller

A Video Display Controller or VDC is an integrated circuit which is the main component in a video signal generator, a device responsible for the production of a TV video signal in a computing or game system. Some VDC's also generate a sound signal, but in that case it's not their main function. Integrated circuit showing memory blocks, logic and input/output pads around the periphery A monolithic integrated circuit (also known as IC, microchip, silicon chip, computer chip or chip) is a miniaturized electronic circuit (consisting mainly of semiconductor devices, as well as passive components) that has been manufactured in the surface... A video signal generator is a type of signal generator which outputs predetermined video and/or television waveforms, and other signals used to stimulate faults in, or aid in parametric measurements of, television and video systems. ... Braun HF 1, Germany, 1958 OT-1471 Belweder, Poland, 1957 Television is a telecommunication system for broadcasting and receiving moving pictures and sound over a distance. ... Composite video is the format of an analog television (picture only) signal before it is combined with a sound signal and modulated onto an RF carrier. ... It has been suggested that this article or section be merged into Analog electronics. ...

VDC's were most often used in the old home-computers of the 80's, but also in some early video game systems. Children playing on a Amstrad CPC 464 in the 1980s. ... The 1980s refers to the years of 1980 to 1989. ... Namcos Pac-Man was a hit, and became a cultural phenomenon. ...

The VDC is always the main component of the the video signal generator logic, but sometimes there are also other supporting chips used, such as RAM's to hold the pixel data, ROM's to hold character font's, or perhaps some discrete logic such as shift registers were necessary to build a complete system. In any case, it's the VDC's responsibility to generate the timing of the necessary video signals, such as the horizontal and vertical synchronisation signals, and the blanking interval signal. Look up RAM, Ram, ram in Wiktionary, the free dictionary. ... This example shows an image with a portion greatly enlarged, in which the individual pixels are rendered as little squares and can easily be seen. ... For the use of the term raster in radio regulation, see frequency raster. ... Read-only memory (ROM) is a class of storage media used in computers and other electronic devices. ... In typography, a typeface is a co-ordinated set of character designs, which usually comprises an alphabet of letters, a set of numerals and a set of punctuation marks. ... A logic gate is an arrangement of electronically-controlled switches used to calculate operations in Boolean algebra. ... In digital circuits a shift register is a group of registers set up in a linear fashion which have their inputs and outputs connected together in such a way that the data is shifted down the line when the circuit is activated. ... A video format describes how one device sends a video pictures to another device, such as the way that a DVD player sends pictures to a television, or a computer to a monitor. ...

Most often the VDC chip is completely integrated in the logic of the main computer system, (its video RAM appears in the memory map of the main CPU), but sometimes it functions as a coprocessor that can manipulate the video RAM contents independently from the main CPU. VRAM an acronym for Video RAM. Generally a term used in computers to describe RAM dedicated to the purpose of displaying bitmap graphics in raster graphics hardware. ... 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. ... This article or section does not cite its references or sources. ...


Video Display Controllers en Video Display Processors

The difference between a VDC and the more modern Video Display Processor (VDP) is not that the VDC's could not generate graphics, but they did not have the special hardware accelerators to create 2D and 3D images, while a typical 1990's VDP does have at least some form of hardware graphics acceleration. Also VDC's often had special hardware for the creation of "sprites", a function that in more modern VDP chips is done with the "Bit Blitter" using the "Bit blit" function. VPU redirects here. ... Suppose the smiley face in the top left corner is an RGB bitmap image. ... In computing, hardware acceleration is the use of of hardware to perform some function faster than is possible in software running on the normal CPU. Examples of hardware acceleration include blitting acceleration functionality in graphics processing units (GPUs) and instructions for complex operations in CPUs. ... 2D computer graphics is the computer-based generation of digital images—mostly from two-dimensional models (such as 2D geometric models, text, and digital images) and by techniques specific to them. ... A 3D rendering with raytracing and ambient occlusion using Blender and Yafray 3D computer graphics are works of graphic art created with the aid of digital computers and 3D software. ... Events and trends Technology Explosive growth of the Internet; decrease in the cost of computers and other technology Reduction in size and cost of mobile phones leads to a massive surge in their popularity Year 2000 problem (commonly known as Y2K) Microsoft Windows operating system becomes virtually ubiquitous on IBM... In computer graphics, a sprite (also known by other names; see Synonyms below) is a two-dimensional image or animation that is integrated into a larger scene. ... A Blitter (acronym for BLock Image TransferrER) is a chip that specialises in bitmap data-transfer using bit blit methods. ... Bit blit (bitblt, blitting etc. ...

One example of a typical Video Display Processor is the "VDP2 32-bit background and scroll plane video display processor" of the Sega Saturn. Another example is the Advanced Graphics Architecture (AGA) chip that was used for the improved graphics of the later generation Amiga computers. The VDP 2 serves as the Sega Saturns background processor. ... The Sega Saturn ) is a 32-bit video game console, first released on November 22, 1994 in Japan, May 11, 1995 in North America and July 8, 1995 in Europe. ... Advanced Graphics Architecture (AGA) was the name used for the improved graphics chipset of the third generation Amiga computers at the beginning of the 1990s. ... The original Amiga 1000 (1985) with Commodore 1080 monitor The Amiga is a family of home/personal computers originally developed by Amiga Corporation as an advanced home entertainment and productivity machine. ...

This said, it is not completely clear when a "Video chip" is a "Video Display Controller" and when it is a "Video Display Processor". For example, the TMS9918 is sometimes called a "Video Display Controller" and sometimes a "Video Display Processor". In general however a "Video Display Processor" has some power to "Process" the contents of the Video RAM (filling an area of RAM for example), while a "Video Display Controller" only controls the timing of the Video synchronisation signals and the access to the Video RAM.

Types of Video Display Controllers

Video Display controllers can be (arbitrarily) divided in several different types (here listed from simple to complex);

  • Video shifters, or "Video shift register based systems" (there is no general agreed upon name for these type of devices) are the most simple type of video controllers, they are, (directly or indirectly) responsible for the video timing signals, but they normaly do not acces the Video RAM directly. They get the video data from the main CPU, a byte at a time, and convert it to a serial bitstream (hence the technical name "Video shifter"). This serial data stream is then used, together with the synchronisation signals, to output a (colour) video signal. The main CPU needs to do the bulk of the work. Normally these chips only support a very low resolution Raster graphics mode.
  • A CRTC, or CRT Controller, generates the video timings and reads video data from a RAM attached to the CRTC, to output it via an external character generator ROM, (for text modes) or directly, (for high resolution graphics modes) to the video output shift register. Because the actual capabilities of the video generator depend for a large degree on the external logic, video generator based on a CRTC chip can have a wide range of capabilities. From very simple (text mode only) systems to very high resolution systems supporting a wide range of colours. Sprites however are normally not supported by these systems.
  • Video interface controllers are much more complex than CRT controllers, and the external circuitry that is needed with a CRTC is embedded in the video controller chip. Sprites are often supported, as are (RAM based) character generators and video RAM dedicated to colour attributes and pallette registers (Color lookup tables) for the high-resolution and/or text-modes.
  • Video coprocessors have their own internal CPU dedicated to reading (and writing) their own video RAM, and converting the contents of this video RAM to a video signal. The main CPU can give commands to the coprocessor, for example to change the video modes or to manipulate the video ram contents. The video coprocessor also controls the (most often RAM based) character generator, the colour attribute RAM, Palette registers and the Spite logic (as long as these exist of course).

Suppose the smiley face in the top left corner is an RGB bitmap image. ... A text mode program communicates with the user by only displaying text and possibly a limited set of predefined semi-graphical characters, which allow the drawing of rudimentary boxes around portions of text, either to highlight the content or to simulate widget or control interface objects found in GUI programs. ... A character encoding consists of a code that pairs a sequence of characters from a given set with something else, such as a sequence of natural numbers, octets or electrical pulses, in order to facilitate the storage of text in computers and the transmission of text through telecommunication networks. ... A character encoding consists of a code that pairs a sequence of characters from a given set with something else, such as a sequence of natural numbers, octets or electrical pulses, in order to facilitate the storage of text in computers and the transmission of text through telecommunication networks. ... A palette, in computer graphics, is a designated subset of the total range of colors supported by a computer graphics system. ... A Colour Look-Up Table (CLUT) is a device which converts the logical colour numbers stored in each pixel of video memory into physical colours, normally represented as RGB triplets, that can be displayed on a computer monitor. ...

List of example VDC's

Examples of Video Display Controllers are:

Video shifters

  • The RCA CDP1861 was a very simple chip, build in (CMOS technology, which was unusual for the time) to complement the RCA 1802 microprocessor, it was mainly used in the COSMAC VIP. It could only support a very low resolution monochrome graphic mode.
  • The "Television Interface Adapter (TIA) is the custom video chip that is the heart of the Atari 2600 games console, a very primitive chip that relied on the 6502 microprocessor to do most of the work, also was used to generate the audio.
  • The Signetics 2637 is the Video controller best known for its use in the Emerson Arcadia 2001.

CRT Controllers Static CMOS Inverter Complementary-symmetry/metal-oxide semiconductor (CMOS) (see-moss, IPA:), is a major class of integrated circuits. ... The RCA (CDP)1802 (aka RCA COSMAC*, COSMAC 1802) is an 8-bit CMOS microprocessor (µP) introduced by RCA in early 1976, and presently being manufactured by Intersil Corporation. ... The RCA Cosmac VIP (1977) was an early microcomputer that was aimed at video games. ... The Television Interface Adapter (TIA) is the custom chip that is the heart of the Atari 2600 games console and was created by Jay Miner of Amiga fame. ... The Atari 2600, released in October 1977, was the first successful video game console to use plug-in cartridges instead of having one or more games built in. ... The MOS Technology 6502 is an 8-bit microprocessor designed by MOS Technology in 1975. ... The Arcadia 2001 is a second-generation 8-bit console released by Emerson Radio Corp. ...

  • The Intel 8275 CRT controller. Was not used in any mainstream system, but was used in some S100 bus systems.
  • The Motorola 6845 is a video address generator first introduced by Motorola and used for the Amstrad CPC, the BBC Micro. It was later used for all the video adapters for the PC such as the MDA, CGA and EGA adapters. In all later VGA compatible adapters the function of the 6845 is reproduced inside the Video Chip.

Video Interface Controllers The S-100 bus was an early computer bus designed as a part of the Altair 8800, generally considered today to be the first personal computer. The S-100 bus was the first industry standard bus for the microcomputer industry, and S-100 computers, processor and peripheral cards, were produced... The Motorola 6845 (commonly MC6845) is a video address generator first introduced by Motorola and used in the CGA and EGA video adapters, Amstrad CPC and BBC Micro. ... Motorola (NYSE: MOT) is a United States-based multinational communications company based in Schaumburg, Illinois, a Chicago suburb. ... The Amstrad CPC was a series of 8-bit home computers produced by Amstrad during the 1980s and early 1990s. ... The BBC Micro, affectionately known as the Beeb, was an early home computer. ... Green screen driven by a Monochrome Display Adapter The Monochrome Display Adapter (MDA, also MDA card, Monochrome Display and Printer Adapter, MDPA) introduced in 1981 was IBMs standard video display card and computer display standard for the PC. The MDA did not have any graphics mode of any kind... The Color Graphics Adapter (CGA), introduced in 1981, was IBMs first color graphics card, and the first color computer display standard for the IBM PC. The standard IBM CGA graphics card was equipped with 16 kilobytes of video memory. ... VGA redirects here. ...

Video Coprocessors 4k TRS-80 Color Computer from 1981, 26-3001 The Radio Shack TRS-80 color computer (also called Tandy Color Computer, or CoCo) was a home computer based around the Motorola 6809E processor and part of the TRS-80 line. ... The Dragon 32 and Dragon 64 were home computers built in the 1980s. ... The VTech Laser 200 was an early 8-bit home microcomputer from 1983, also sold as the Salora Fellow, the Texet TX8000 (in the United Kingdom) and the Dick Smith VZ 200 (in Australia). ... The Atom was Acorns first computer to be aimed squarely at the home market. ... The VIC (Video Interface Chip), specifically known as the MOS Technology 6560 (NTSC version) / 6561 (PAL version), is the integrated circuit chip responsible for generating video graphics and sound in the Commodore VIC-20 home computer. ... VIC-20 with accessories. ... The VIC-II (Video Interface Chip II), specifically known as the MOS Technology 6567/8562/8564 (NTSC versions), 6569/8565/8566 (PAL), is the integrated circuit chip tasked with generating composite video graphics and DRAM refresh signals in the Commodore 64 and C128 home computers. ... The Commodore 64 is the best selling single personal computer model of all time. ... It has been suggested that MOS Technology 8568 be merged into this article or section. ... The Commodore 128 (C128, CBM 128, C=128) home/personal computer was Commodore Business Machines (CBM)s last commercially released 8-bit machine. ... The 7360 Text Editing Device (TED) was an integrated circuit made by MOS Technology. ... Commodore Plus/4. ... The Commodore 16 was a home computer made by Commodore with a 6502-compatible 7501 CPU, released in 1984. ...

  • The ANTIC (Alpha-Numeric Television Interface Circuit) was an early video system chip used in the Atari 8-bit family of microcomputers. It could read a "Display list" with its own built in CPU and use this data to generate a complex video signal.
  • The TMS9918 is known as the Video Display Processor (VDP) and was first designed for the Texas Instruments TI-99/4, but was later also used in systems like the MSX (MSX-1), Coleco Vision, Memotech MTX500/MTX512 and RS128, and for the Sega SG-1000 and SC-3000.
  • The Yamaha V9938 is an improved version of the TMS9918, and was mainly used in the MSX2.
  • The Yamaha V9958 is the Video Display Processor (VDP) mainly used in the MSX 2+ and MSX turbo R computers.

AntiC (or JLint) is a programming tool for finding programming errors in source code. ... An Atari 800XL, one of the most popular machines in the series. ... The Commodore 64 was one of the most popular microcomputers of its era, and is the best selling home computer of all time. ... Display list - a group of GL (graphics language, e. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... Texas Instruments (NYSE: TXN), better known in the electronics industry (and popularly) as TI, is an American company based in Dallas, Texas, USA, renowned for developing and commercializing semiconductor and computer technology. ... ... Sony MSX 1, Model HitBit-10-P MSX was the name of a standardized home computer architecture in the 1980s. ... The ColecoVision was Coleco Industries second generation home video game console, released in August of 1982. ... Memotech was a company based in Witney in Oxfordshire, England. ... The Memotech MTX500, MTX512 and RS128 were a series of Zilog Z80A processor-based home computers released by Memotech in 1983 and 1984. ... The Memotech MTX500, MTX512 and RS128 were a series of Zilog Z80A processor-based home computers released by Memotech in 1983 and 1984. ... The Memotech MTX500, MTX512 and RS128 were a series of Zilog Z80A processor-based home computers released by Memotech in 1983 and 1984. ... Sega Corporation ) is an international video game software and hardware developing company, and a former home computer and console manufacturer. ... The SG-1000, which stands for Sega Game 1000, is a cartridge-based video game console manufactured by Sega. ... Sega SC-3000 and joystick The SC-3000 was the computer equivalent of the SG-1000 cartridge-based gaming console manufactured by Sega. ... A Video Display Processor (VDP) used in MSX 80s home computers. ... Sony MSX 1, Model HitBit-10-P MSX was the name of a standardized home computer architecture in the 1980s. ... The Yamaha V9958 is a Video Display Processor (VDP) used in MSX 80s home computers. ...

Alternatives to using a VDC chip

Note that many older home-computer did not use a VDP-chip, but build the whole video display controller from a lot of discrete logic chips, (examples are the Apple II, PET, and TRS-80). Because these methods are very flexible the video display generators could be very capable, (or extremely primitive, depending of the quality of the design) but also needed a lot of components. A Motorola 68000-based computer with various TTL chips. ... The Apple II was one of the most popular personal computers of the 1980s. ... Pets and humans often contribute toward the happiness of the other in a pet relationship. ... TRS-80 Model I. TRS-80 was Tandy Corporations desktop microcomputer model line, and sold through Tandys RadioShack stores, in the late-1970s and 1980s. ...

Others used some form of early programmable logic chips, (examples are the Sinclair Spectrum and ZX-81 systems). These systems could build a very capable systems with relatively few components, but the low transistor count of early programmable logic meant that the capabilities of these systems often were less impressive than those using video interface controllers or video coprocessors. A field-programmable gate array or FPGA is a gate array that can be reprogrammed after it is manufactured, rather than having its programming fixed during the manufacturing — a programmable logic device. ... The Sinclair ZX Spectrum was a small home computer released in the United Kingdom in 1982 by Sinclair Research. ...

Later solutions

With Moore's law working, integrated circuits became more and more complex. The simple Video Display Controllers were slowly replaced by chips that had build in video processing logic such as Blitter's and other logic to manipulate the video RAM contents to do things like drawing lines, filling areas, or drawing fonts. Later chips also got special hardware to draw triangles to support 3D images, gained hardware Z-buffers and many other methods to accelerate the drawing of 3D pictures. Current Video generator chips almost always are "Graphics processing units" (GPU's) Growth of transistor counts for Intel processors (dots) and Moores Law (upper line=18 months; lower line=24 months) Moores Law is the empirical observation made in 1965 that the number of transistors on an integrated circuit for minimum component cost doubles every 24 months. ... A Blitter (acronym for BLock Image TransferrER) is a chip that specialises in bitmap data-transfer using bit blit methods. ... Z-buffer data In computer graphics, z-buffering is the management of image depth coordinates in three-dimensional (3-D) graphics, usually done in hardware, sometimes in software. ... A Graphics Processing Unit or GPU, also called Visual Processing Unit or VPU is the microprocessor of a graphics card (or graphics accelerator). ...

See also

List of home computers by video hardware



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