Editing MOS Technology Agnus

[[File:Commodore Amiga 1000 - main board - MOS 8367R0-7824.jpg|300px|thumb|MOS 8367R0 – Agnus]]
The '''[[MOS Technology]] "Agnus"''', usually called '''Agnus''', is an [[integrated circuit]] in the custom [[chipset]] of the [[Amiga]] computer.  The '''Agnus''', [[Original Chip Set#Denise|Denise]] and [[Original Chip Set#Paula|Paula]] chips collectively formed the [[Amiga Original Chip Set|OCS]] and [[Amiga Enhanced Chip Set|ECS]] chipsets.

The Agnus is the Address Generator Chip. Its main function, in chip area, is the [[random-access memory|RAM]] Address Generator and Register Address Encoder which handles all [[Direct Memory Access|DMA]] addresses. The 8361 Agnus is made up of approximately 21000 [[transistor]]s and contains DMA Channel Controllers. The [[Amiga Original Chip Set#Blitter|Blitter]] and [[Amiga Original Chip Set#Copper|Copper]] are also contained here. Originally Agnus was fabricated in 5&nbsp;μm manufacturing process like all [[Amiga Original Chip Set|OCS]] chipset.

Agnus features:
* Memory controller ("Chip" memory that can be accessed by the processor and the chipset)
* The [[Amiga Original Chip Set#Blitter|Blitter]], a [[Raster graphics|bitmap]] manipulator. The Blitter is capable of copying blocks of display data, or any arbitrary data in the chip 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.
* "[[Amiga Original Chip Set#Copper|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
* Generates the system clock from the 28&nbsp;MHz oscillator
* Video timing

'''Agnus''' was replaced by [[Alice (computer chip)|Alice]] in the [[Amiga 4000]] and [[Amiga 1200]] when the [[Amiga Advanced Graphics Architecture|AGA]] chipset was introduced in 1992.

== Chips by capability ==
[[File:CBM 8370R3 top metal.jpg|thumb|Agnus chip (MOS Technology 8370 R3)]]

* '''[[Amiga Original Chip Set|OCS]] Agnus''' which can address up to '''512 KB''' of [[Chip RAM]] (PLCC versions add 512 KB of pseudo-fast RAM)
** 8361 ([[Dual in-line package|DIP]]) - [[Amiga 1000]] (NTSC); [[Amiga 2000]] model A (NTSC)
** 8367 (DIP) - [[Amiga 1000]] (PAL); [[Amiga 2000]] model A (PAL)
** 8370 ([[Plastic leaded chip carrier|PLCC]]) - [[Amiga 500]] to Rev 5.x (NTSC); [[Amiga 2000]] model B to Rev 4.5 (NTSC)
** 8371 ([[Plastic leaded chip carrier|PLCC]]) - [[Amiga 500]] to Rev 5.x (PAL); [[Amiga 2000]] model B to Rev 4.5 (PAL)
* '''[[Amiga Enhanced Chip Set|ECS]] Agnus''' which can address up to '''1 MB''' of [[Chip RAM]]
** 8372 - no data<nowiki>*</nowiki>
** 8372A - [[Amiga 500]] from Rev 6 (NTSC/PAL); [[Amiga 2000]] model B from Rev 6.0 to Rev 6.3 (NTSC/PAL); [[Amiga CDTV|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)
* '''[[Amiga Enhanced Chip Set|ECS]] 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+|Amiga 500 Plus]]; [[Amiga 600]] (PAL)
** 8375 (NTSC) - [[Amiga 600]] (NTSC)

<nowiki>*</nowiki> Somewhere 8372A Agnus mentioned as simply "8372".

== Chips by package ==
* 48-lead [[Dual in-line package|DIP]] '''Agnus''' (aka '''thin Agnus'''): 8361; 8367
* 84-contact [[plastic leaded chip carrier|PLCC]] '''Fat Agnus''' (named '''Fat Lady''' on most Amiga 2000 motherboards) 8370; 8371; 8372; 8372A; 8372AB; 8372B; 8375

'''Notes'''<br>'''Fat Agnus 1MB''' and '''Fat Agnus 2MB''' also known as Super Agnus; Super Fat Agnus; Fatter Agnus; Big Agnus; Big Fat Agnus.

== DMA Channels ==
{| class="wikitable"
! Priority !! Name !! Count !! Cycles/Rasterline !! Chip !! Notes
|-
|
| MPU
| 1
| varying
| CPU
|
|-
| A
| Blitter
| 4
| varying
| Agnus (internal)
| yields 1/4 cycles to CPU when ''BLTPRI'' not active
|-
| B
| Bitplane
| 6
| 80
| Denise
| impairs sprite channels on severe [[overscan]]
|-
| C
| Copper
| 1
| varying
| Agnus (internal)
|
|-
| D
| Audio
| 4
| 4
| Paula
|
|-
| E
| [[Sprite (computer graphics)|Sprites]]
| 8
| 16
| Denise
|
|-
| F
| Disk
| 1
| 3
| Paula
|
|-
| G
| Memory Refresh
| 1
| 4
| -
|
|-
| colspan="5" | Reference: Amiga 500 plus Service Manual
|}

== Pinout ==

=== PLCC versions ===
When replacing or upgrading chips, pinouts need to be taken care of.  Types are just mentioned for reference; four-digit types and pinouts/usage are ''not'' consistent.<ref>{{cite newsgroup
 | title = Difference of 8372A vs 8375
 | author = George Robbins
 | date = 14 October 1992
 | newsgroup = comp.sys.amiga.hardware
 | message-id = 35861@cbmvax.commodore.com
 | url = http://groups.google.co.uk/group/comp.sys.amiga.hardware/msg/259d7e187bd3b044
 | access-date = 1 October 2018
 }}</ref>

{| class="wikitable"
|-
! rowspan=3 | Pin
!OCS/ECS
!colspan=2 | ECS
!AGA (Alice)
! rowspan=3 | Description
|-
!A500/2000
!A3000
!A500+/600
!A4000/1200
|-
|''8370/1''
|''8372''
|''8375''
|''8374''
|-
|1
|RD13
|DRD13
|DRD13
|DRD13
|Data Bus 16 bit, bit 13
|-
|2
|RD12
|DRD12
|DRD12
|DRD12
|rowspan=12 style="text-align: center" | .<br />.<br />.
|-
|3
|RD11
|DRD11
|DRD11
|DRD11
|-
|4
|RD10
|DRD10
|DRD10
|DRD10
|-
|5
|RD9
|DRD9
|DRD9
|DRD9
|-
|6
|RD8
|DRD8
|DRD8
|DRD8
|-
|7
|RD7
|DRD7
|DRD7
|DRD7
|-
|8
|RD6
|DRD6
|DRD6
|DRD6
|-
|9
|RD5
|DRD5
|DRD5
|DRD5
|-
|10
|RD4
|DRD4
|DRD4
|DRD4
|-
|11
|RD3
|DRD3
|DRD3
|DRD3
|-
|12
|RD2
|DRD2
|DRD2
|DRD2
|-
|13
|RD1
|DRD1
|DRD1
|DRD1
|-
|14
|RD0
|DRD0
|DRD0
|DRD0
|Data Bus 16 bit, bit 0
|-
|15
|Vcc
|Vcc
|Vcc
|Vcc1
| +5V ±5%
|-
|16
|RST*
|_RESET
|_RESET
|/RESET
|Global RESETn, low active
|-
|17
|INT3
|_INTR
|_INTR
|/INTR
|-
|18
|DMAL
|DMAL
|DMAL
|DMAL
|-
|19
|BLS*
|_BLISS
|_BLISS
|/BLS
|-
|20
|DBR*
|_BLIT
|_BLIT
|/DBR
|-
|21
|RRW
|_WE
|_WE
|/WE
|-
|22
|PRW
|R/W
|R/W
|R/W
|-
|23
|RGEN*
|_REGEN
|_REGEN
|_REGEN
|-
|24
|AS*
|_AS
|_AS
|NC2
|-
|25
|RAMEN*
|_RAMEN
|_RAMEN
|/RAMEN
|-
|26
|RGA8
|RGA8
|RGA8
|RGA8
|-
|27
|RGA7
|RGA7
|RGA7
|RGA7
|-
|28
|RGA6
|RGA6
|RGA6
|RGA6
|-
|29
|RGA5
|RGA5
|RGA5
|RGA5
|-
|30
|RGA4
|RGA4
|RGA4
|RGA4
|-
|31
|RGA3
|RGA3
|RGA3
|RGA3
|-
|32
|RGA2
|RGA2
|RGA2
|RGA2
|-
|33
|RGA1
|RGA1
|RGA1
|RGA1
|-
|34
|28&nbsp;MHz
|28&nbsp;MHz
|28&nbsp;MHz
|SCLK
|-
|35
|XCLK
|A20
|A20
|A20
|-
|36
|XCLKEN*
|_XCLKEN
|_CDAC
|14&nbsp;MHz
|-
|37
|CDAC*
|_CDAC
|7&nbsp;MHz
|/CDAC
|-
|38
|7&nbsp;MHz
|7&nbsp;MHz
|CCKQ
|7&nbsp;MHz
|-
|39
|CCKQ
|CCKQ
|CCK
|CCKQ
|-
|40
|CCK
|CCK
|14M
|CCK
|-
|41
|TEST
|TEST
|GND
|/NTSC
|-
|42
|Vss
|Vss1
|DRA0
|GND2
|-
|43
|MA0
|DRA0
|DRA1
|DRA0
|Memory address bus 9 bit, bit 0 (except 8375 which is bit 1)
|-
|44
|MA1
|DRA1
|DRA2
|DRA1
|rowspan=7 style="text-align: center" | .<br />.<br />.
|-
|45
|MA2
|DRA2
|DRA3
|DRA2
|-
|46
|MA3
|DRA3
|DRA4
|DRA3
|-
|47
|MA4
|DRA4
|DRA5
|DRA4
|-
|48
|MA5
|DRA5
|DRA6
|DRA5
|-
|49
|MA6
|DRA6
|DRA7
|DRA6
|-
|50
|MA7
|DRA7
|DRA8
|DRA7
|-
|51
|MA8
|DRA8
|_LDS
|DRA8
|Memory address bus 9 bit, bit 8 (except 8375 which is bit _LDS)
|-
|52
|LDS*
|_LDS
|_UDS
|Vcc2
|-
|53
|UDS*
|_UDS
|_CASL
|NC1
|-
|54
|CASL*
|_CASL
|_CASU
|/CAS
|-
|55
|CASU*
|_CASU
|DRA9
|Vbb
|-
|56
|RAS1*
|DRA9
|_RAS1
|DRA9
|-
|57
|RAS0*
|_RAS
|_RAS0
|/RAS
|-
|58
|Vss
|Vss2
|GND
|GND3
|-
|59
|A19
|A19
|A19
|A19
|-
|60
|A1
|A1
|A1
|A1
|-
|61
|A2
|A2
|A2
|A2
|-
|62
|A3
|A3
|A3
|A3
|-
|63
|A4
|A4
|A4
|A4
|-
|64
|A5
|A5
|A5
|A5
|-
|65
|A6
|A6
|A6
|A6
|-
|66
|A7
|A7
|A7
|A7
|-
|67
|A8
|A8
|A8
|A8
|-
|68
|A9
|A9
|A9
|A9
|-
|69
|A10
|A10
|A10
|A10
|-
|70
|A11
|A11
|A11
|A11
|-
|71
|A12
|A12
|A12
|A12
|-
|72
|A13
|A13
|A13
|A13
|-
|73
|A14
|A14
|A14
|A14
|-
|74
|A15
|A15
|A15
|A15
|-
|75
|A16
|A16
|A16
|A16
|-
|76
|A17
|A17
|A17
|A17
|-
|77
|A18
|A18
|A18
|A18
|-
|78
|LP*
|_LPEN
|_LPEN
|/LPEN
|-
|79
|VSY*
|_VSYNC
|_VSYNC
|/VSYNC
|-
|80
|CSY*
|_CSYNC
|_CSYNC
|/CSYNC
|-
|81
|HSY*
|_HSYNC
|_HSYNC
|/HSYNC
|-
|82
|Vss
|Vss3
|GND
|GND1
|Ground, common on whole board
|-
|83
|RD15
|DRD15
|DRD15
|DRD15
|Data Bus 16 bit, bit 15
|-
|84
|RD14
|DRD14
|DRD14
|DRD14
|Data Bus 16 bit, bit 14
|}
References: A500 Service Training, A3000 Service Manual, A500+ Service Manual, A1200 schematics

== See also ==
{{Portal|Amiga}}

== References ==
;Sources
* AMIGA 1000 ASSEMBLY LEVEL REPAIR (Commodore-Amiga, Inc.) 1985 PN 314038-01 [https://web.archive.org/web/20060514232237/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 [https://web.archive.org/web/20060514232237/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) [https://web.archive.org/web/20060514232237/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 [https://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 [https://web.archive.org/web/20070928222058/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 [https://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]
* [https://bboah.com/index.php?action=artikel&cat=51&id=2174 Big Book of Amiga Hardware]
* '''alexh''' on [https://web.archive.org/web/20071118092300/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]
* [https://web.archive.org/web/20070928011404/http://www.titan.co.nz/Amigaak/AA060193.htm AMIGA Auckland Inc.]
* [https://web.archive.org/web/20030425082107/http://amigau.com/natamiga/chipsandpartnumbers.htm Amiga University]
* [https://web.archive.org/web/20070608013202/http://cbmmuseum.kuto.de/zusatz_8361_agnus.html Commodore Computer Online Museum]
;Notes
{{Reflist}}

{{Amiga hardware}}

{{DEFAULTSORT:Mos Technology Agnus}}
[[Category:MOS Technology integrated circuits]]
[[Category:Amiga]]