The High-Performance Graphics Display Controller 7220 (commonly
Release date | 1981-12 |
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History | |
Successor |
The
Details
editThe project was started in 1979, with trial production in 1980 and mass production starting in December 1981.[3][4] It was first used in the NEC N5200 (known in North America as the NEC APC or "Advanced Personal Computer"[5]) in 1981.[6] The N5200 sported a 5 MHz Intel 8086 processor on a 16-bit bus, and came with a text-only display board using a
In 1981, an English language paper written in 1980 by Tetsuji Oguchi, Misao Higuchi, Takashi Uno, Michiori Kamaya and Munekazu Suzuki was published in the IEEE.[7] NEC deployed the chip in other computers, such as the NEC PC-9801, and NEC's APC II and later APC III computers, and also released it to other manufacturers in Japan, starting in 1982. The same year, the 7220 was revealed in North America by NEC Information Systems, the US arm of NEC.
By 1983, it was used in other early computers, from NEC and other companies including Digital Equipment Corporation and Wang Laboratories.[8]
While most computers used memory mapped character, or bit-mapped displays, those with a
Additionally, the controller had hardware assist features for drawing straight lines and sectors of circles. It would draw pixels along a line, a circular arc or from user defined characters in under 800 ns. This released the host computer to continue other processing while the drawing operation continued.
The high-resolution capability permitted support for glyph-based languages like Japanese that were difficult to comprehensively support with character-based displays. The large memory space, combined with hardware viewport registers permitted smooth high-speed scrolling.
Compatibility with Direct memory access hardware made it possible to move bitmaps to and from the controller memory at bus-limited rates. In this way, bitmaps could be Blitted around the display at high speed and the controller kept focused on the more complex rendering tasks.
The controller could address a maximum 1024 × 1024 pixel display with four-bit colour depth. It included a light pen interface that synchronised the pixel clock to input signals without additional processor support.
GKS was available on CP/M and MS-DOS systems and formed the basis of early 1980s
A few years after its introduction, one journalist said "The 7220 GDC chip is a component that even some of NEC's competitors have found too good to pass up."[8] When the Apple Lisa was announced in 1983, the press raised questions on why the popular 7220 was not used.[9][10] Bruce Daniels pointed out that the Lisa primarily used raster graphics (known as bitmap graphics at the time), which could be implemented with less expensive hardware support. Instead, graphics primitives were written in software. Development manager Wayne Rosing added that although the team knew about the 7220, it was not quite available when the design began. There were also restrictions on when the display memory could be accessed: only during certain times in the vertical refresh cycle.[9]
IBM PC compatible variants of NEC
Variants
editVariants included:
- Intel licensed the design and called it the 82720 graphics display controller.[11][12] Announced in 1982, it was the first of what would become a long line of Intel graphics processing units.[13][14]
- East Germany (the German Democratic Republic) produced a replica designated U82720, used with the U880 replica of the Zilog Z80.[15]
- The faster complementary metal–oxide–semiconductor (CMOS) variant was given the designation
μ PD72020. - A follow-on project produced the
μ PD72120 Advanced Graphics Display Controller (AGDC) which was faster and supported a 16-bit interface. It was named one of the "Top 100" products of 1987 by Electronics Design.[16]
Internals
editTwo I/O channels are used, addressing A0 and A1. Reading A0 retrieves the 7220 status. Reading A1 fetches the first byte from the internal queue. Writing to the 7220 uses both registers; A1 for writing the command, A0 for writing the parameters to the queue.[1] The parts had an 8-bit data path.[17] Parts were available with clocks running from 4 MHz to 5.5 MHz, which was considered relatively high-performance for the time.[10]
References
edit- ^ a b Dampf, Guido (1986). "Graphics with the NEC 7220: Direct access with Turbo Pascal". Retrieved 27 July 2013. (Translation of "Grafik mit dem 7220 von NEC", mc, 1986, H11, pp. 54-65)
- ^ F. Robert A. Hopgood; Roger J. Hubbold; David A. Duce, eds. (1986). Advances in Computer Graphics II. Springer. p. 169. ISBN 9783540169109.
Perhaps the best known one is the NEC 7220.
- ^ Oguchi, Tetsuji. "LSI Products that I was involved in the design". Oguchi R&D. Archived from the original on 2021-05-16. Retrieved 2021-11-02.
- ^ Oguchi, Tetsuji. "Abstract History of GDC Development" (PDF). Oguchi R&D. Archived (PDF) from the original on 2019-03-13. Retrieved 2021-11-02.
- ^ "Daves Old Computers - Nippon Electric Company - APC". Daves Old Computers. Archived from the original on 2021-04-20. Retrieved 2021-11-02.
- ^
田辺 皓正 , ed. (1983-04-30). マイクロコンピュータシリーズ15 8086マイクロコンピュータ (in Japanese).丸善 株式会社 . p. 254. - ^ Tetsuji Oguchi; Misao Higuchi; Takashi Uno; Michiori Kamaya; Munekazu Suzuki (February 1981). "A single-chip graphic display controller" (PDF). 1981 IEEE International Solid-State Circuits Conference. Digest of Technical Papers. IEEE. pp. 170–171. doi:10.1109/ISSCC.1981.1156160. S2CID 20765458.
- ^ a b David Needle (March 21, 1983). "NEC's 7220 GDC chip allows high-resolution color graphics". Info World. pp. 31–34. Retrieved July 29, 2013.
- ^ a b Wayne Rosing, Bruce Daniels, and Larry Tesler (February 1983). "An Interview with Wayne Rosing, Bruce Daniels, and Larry Tesler: A behind-the-scenes look at the development of Apple's Lisa". Byte Magazine. pp. 90–114. Retrieved July 29, 2013.
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: CS1 maint: multiple names: authors list (link) - ^ a b Hal W. Hardenberg (April 1983). "An Introduction to the 7220". DTACK Grounded. Digital Acoustics. pp. 8–9. Retrieved July 31, 2013.
- ^ Tsay, Changon (1986-01-01). "A graphics system design based on the INTEL 82720 graphics display controller". ETD Collection for University of Texas, el Paso: 1–152.
- ^ Intel Corporation, "Cover Story: A Picture of The Future: Drawing On Computers", Solutions, November/December 1983, Page 2
- ^ "Intel Corporation Annual Report" (PDF). Intel. 1982. Retrieved July 27, 2013.
- ^ 82720 GDC Application Manual (PDF). Intel, reprinted from NEC. July 1983. Retrieved May 30, 2024.
- ^ "Integrierte Schaltkreise: Schaltkreis U82720". Robotron Technik. Retrieved July 27, 2013. (in German)
- ^ "Graphics Display Controller simplifies programming" (PDF). Electronics Design. May 14, 1987. p. 106.
- ^ "
μ PD7220/GDC,μ PD7220-1/μ PD7220-2 Graphics Display Controller" (PDF). The data sheet. NEC. April 7, 1983. Retrieved July 29, 2013.
External links
edit- uPD7220/uPD7220A User Manual, December 1985
- uPD7220/uPD7220A Design Manual, 1982
- Source code of driver for CP/M-86
- 7220 and 72020 data sheets
- "Article on
μ PD7220" (PDF). Nikkei Electronics. (in Japanese)