MOS Technology Agnus

The MOS Technology "Agnus", usually called Agnus is an integrated circuit in the custom chipset of the Commodore Amiga computer. The Agnus, Denise and Paula chips collectively formed the OCS and ECS chipsets.
The Agnus is the Address Generator Chip. Its main function, in chip area, is the RAM Address Generator and Register Address Encoder which all DMA addresses.The 8361 Agnus is made up of approximately 21000 transistors and contains DMA Channel Controllers. The Blitter and Copper are also contained here.

Agnus features:
* The Blitter, a Bitmap image manipulator. The Blitter is capable of copying blocks of display data, or any arbitrary data in the on-board memory, at high speed with various raster operations as well as drawing pixel perfect lines and filling outlined polygons, while freeing the CPU for concurrent tasks.
* "Copper" a display synchronized co-processor.
* 25 Direct Memory Access (DMA) channels, allowing graphics, sound and I/O to be used with minimal CPU intervention.
* DRAM refresh controller.
* Memory controller (Memory that can be accessed by the processor and the chipset)
* Generates the system clock from the 28 MHz oscillator
* Video timing.

Agnus was replaced by Alice in the Amiga 4000 and Amiga 1200 when the AGA chipset was introduced in 1992.

Chips by capability

* Agnus which can address up to 512 KB of Chip RAM
** 8361 - Amiga 1000 (NTSC); Amiga 2000 model A (NTSC)
** 8367 - Amiga 1000 (PAL); Amiga 2000 model A (PAL)
** 8370 - Amiga 500 to Rev 5.x (NTSC); Amiga 2000 model B to Rev 4.5 (NTSC)
** 8371 - Amiga 500 to Rev 5.x (PAL); Amiga 2000 model B to Rev 4.5 (PAL)

* Agnus which can address up to 1 MB of Chip RAM
** 8372 - no data*
** 8372A - Amiga 500 from Rev 6 (NTSC/PAL); Amiga 2000 model B from Rev 6.0 to Rev 6.3 (NTSC/PAL); Commodore CDTV
** 8375 (318069-16 only) (PAL) - Amiga 500 from Rev 6 (PAL); Amiga 2000 model B from Rev 6.4 (PAL)
** 8375 (318069-17 only) (NTSC) - Amiga 500 from Rev 6 (NTSC); Amiga 2000 model B from Rev 6.4 (NTSC)

* Agnus which can address up to 2 MB of Chip RAM
** 8372AB - Amiga 3000 from Rev 6.1 to Rev 8.9 (NTSC/PAL)
** 8372B - Amiga 3000 Rev 9 (NTSC/PAL)
** 8375 (PAL) - Amiga 500 Plus; Amiga 600 (PAL)
** 8375 (NTSC) - Amiga 600 (NTSC)

* Somewhere 8372A Agnus mentioned as simply "8372".

Chips by package

* 48-lead DIP Agnus (aka thin Agnus): 8361; 8367

* 84-contact PLCC Fat Agnus (sometimes on the motherboard named as Fat Lady) 8370; 8371; 3872; 8372A; 8372AB; 8372B; 8375

Notes
Fat Agnus 1MB and Fat Agnus 2MB usually known as Super Agnus; Super Fat Agnus; Fatter Agnus; Big Agnus; Big Fat Agnus; Super Fat Agnus, but these aren't official names.

Sources

* AMIGA 1000 ASSEMBLY LEVEL REPAIR (Commodore-Amiga, Inc.) 1985 PN 314038-01 [http://www.shiftreload.com.au/users/4x4/schematics/index.html Dave's Amiga Schematics and Manuals]
* Commodore Amiga A500/A2000 Technical Reference Manual (Commodore-Amiga, Inc.) 1987 [http://www.shiftreload.com.au/users/4x4/schematics/index.html Dave's Amiga Schematics and Manuals]
* A500 SYSTEM SCHEMATICS COMPONENT PART LIST (Rev 6A/7) [http://www.shiftreload.com.au/users/4x4/schematics/index.html Dave's Amiga Schematics and Manuals]
* A3000 SYSTEM SCHEMATICS (Commodore Business Machines, Inc.) March, 1990 PN-314677-01 [http://www.1000bit.it/support/schema/commodore/a3000/A3000_schemas.pdf www.1000bit.net]
* CDTV SERVICE MANUAL (Commodore International Spare GmbH) May, 1991 PN-400403-01 [http://www.ianstedman.co.uk/Downloads/cdtv-schematics.zip www.ianstedman.co.uk (ZIP-file)]
* A500 PLUS SERVICE MANUAL (Commodore International Spare GmbH) October, 1991 PN-400420-01 [http://www.1000bit.it/support/manuali/commodore/a500plus_sm/amiga500plus_sm.pdf www.1000bit.net]
* A600 SYSTEM SCHEMATICS (Commodore International Spare GmbH) April, 1992 PN-400422-02 [http://www.1000bit.it/support/manuali/commodore/a600_sm/a600_sm.pdf www.1000bit.net]
* [http://obligement.free.fr/articles/chipsetamiga.php OBLIGEMENT: les chipsets de l'Amiga]
* [http://amigahardware.mariomisic.de/cgi-bin/showhardware_en.cgi?HARDID=1448 http://hardware.amigafuture.de/ Amiga Future (Big Book of Amiga Hardware)]
* alexh on [http://eab.abime.net/archive/index.php/t-21961.html English Amiga Board] (Agnus 8372B info)
* National Amiga Inc. [http://l8r.net/technical/t-achips.shtml mirrored on l8r.net]
* [http://members.chello.hu/varga.gabor8/Amiga/ Marketed Commodore Amiga models]
* [http://www.titan.co.nz/Amigaak/AA060193.htm AMIGA Auckland Inc.]
* [http://www.amigau.com/natamiga/chipsandpartnumbers.htm Amiga University]
* [http://cbmmuseum.kuto.de/zusatz_8361_agnus.html Commodore Computer Online Museum]