Amiga Custom Chips

"Agnus"

The Agnus is responsible for controlling around 25 system DMA channels, the generation of various system clocks in some Amiga's and for addressing Chip RAM. Infact, Chip Memory is so called because it's addressable by the system's custom chips, unlike Fast Memory. The Agnus also cotains an integrated Copper (co-processor) which controls aspects of the Amiga's display such as draggable screens, and the infamous "copper scrolls". The Amiga's blitter is also located in the Agnus chip and is responsible for moving rectangular areas of memory efficiently as possible. This may not sound particularly spectacular but the blitter is twice as fast as the 68000 at moving blocks of memory and is capable of doing it asynchronously with the 68000, meaning the processor is totally free for other operations. The blitter is particularly useful for graphics operations. Agnus is found in the OCS & ECS chipsets, and is the equivalent of Alice in the AGA chipset.

Chip Name	Chip Number	Part Number	Used In
Agnus (512K)	8361	252125-01	A1000 (NTSC), A2000A (NTSC)
Agnus (512K)	8361 R3
Agnus (512K)	8367	252362-01	A1000 (PAL), A2000A (PAL)
Agnus (512K)	8370	318070-01	A500 (NTSC), A2000 (NTSC)
Agnus (512K)	8371	318071-01	A500 (PAL), A2000 (PAL)
Agnus (1MB)	8372A	318069-02	A500 (PAL), A2000 (PAL/NTSC)
Agnus (1MB)	8372A	318069-029	A500 (PAL), A2000 (PAL/NTSC)
Agnus (2MB)	8372AB	318069-03	A3000 (PAL), A3000T (PAL) (came after 8375B)
Agnus (2MB)	8372AB	318069-039	A3000 (NTSC)
Agnus (2MB)	8372B	318069-03	MegAChip (NTSC)
Agnus (2MB)	8375 R0	318069-18	A500+ (PAL), A600 (PAL)
Agnus (2MB)	8375	318069-10	A600 (PAL)
Agnus (2MB)	8375 R2	318069-10	A500+ (PAL), A600 (PAL)
Agnus (2MB)	8375	318069-11	A600 (NTSC), MegAChip (NTSC), Mini Megi Chip (NTSC)
Agnus (2MB)	8375 R2	318069-11	Mini Mega Chip (NTSC)
Agnus (2MB)	8375	318069-17	A500 (NTSC), A2000 (NTSC)
Agnus (2MB)	8375	318069-19	A3000 (NTSC), A3000T (NTSC)
Agnus (2MB)	8375	390544-01	A500+ (PAL), A600 (PAL)
Agnus (2MB)	8375	390544-02	A500+ (NTSC), A600 (NTSC)

 

"Akiko"

The Akiko chip is only found in the CD32 and is primarily responsible for peforming the chunky to planar routines. The Amiga's native display is known as "planar" and planar displays are easy to manipulate for things like scrolling, however "chunky" displays are particularly easy to manipulate for things like 3D graphics routines. The Akiko chip allows the chunky to planar conversion to be done in hardware, instead of software which would otherwise slow the system down. The Akiko is also responsible for implementing some of the control logic for the built-in CDROM, as well as for controlling the serial, "AUX" port on the CD32.

Chip Name	Chip Number	Part Number	Used In
Akiko (REV 0)	9327AS 413921 VY12246-2	391563-01	CD32

 

"Alice"

Alice is responsible for controlling around 25 system DMA channels and addressing Chip RAM. Infact, Chip Memory is so called because it's addressable by the system's custom chips, unlike Fast Memory. Alice also cotains an integrated Copper (co-processor) which controls aspects of the Amiga's display such as draggable screens, and the infamous "copper scrolls". The Amiga's blitter is also located in the Agnus chip and is responsible for moving rectangular areas of memory efficiently as possible. This may not sound particularly spectacular but the blitter is up to twice as fast as the processor at moving blocks of memory and is capable of doing it asynchronously with the processor, meaning the processor is totally free for other operations. The blitter is particularly useful for graphics operations. Alice is found in the AGA chipset, and is equivalent to Agnus found in the OCS and ECS chipsets.

Chip Name	Chip Number	Part Number	Used In
Alice (2MB)	8374	391010-01	A1200, A4000, A4000T, CD32, AA3000

 

"Amber"

The Amber is responsible for scandoubling and flicker fixing the Amiga's native display (~15.5Khz) to ~31Khz for output to a standard PC VGA/SVGA monitor. It is only found in the A3000 series machines such as the A3000, A3000UX, A3000T and A3500. However the same chip can also be found on a separate card called the A2320 which can be used in other models of Amiga that have a video slot.

Chip Name	Chip Number	Part Number	Used In
Amber	51	390538-03	A3000, A2320

 

"Bridgette"

Bridgette is only found in the A4000 and A4000T and is an integrated bus buffer.

Chip Name	Chip Number	Part Number	Used In
Bridgette	??	391380-01	A4000, A4000T

 

"Budgie"

Budgie is a DRAM and bus controller, only found in the A1200. The Budgie chip in some ways is like a baby version of the buster chip as it also handles the trapdoor slot, which is almost electrically a Zorro II slot.

Chip Name	Part Number	Used In
Budgie Rev 0	391425-01	A1200
Budgie A	391425-02	A1200

 

"Buster"

The Buster is the bus controller and handles Zorro II and Zorro III (for later versions) I/O operations and bus arbitration.

The Buster - according to Dave Haynie

Though you think it's the same chip, there are actually two Busters: Level I and Level II. The Level I Buster, up to Rev 7, is used in all A3000 family machines, and it does NOT support Zorro III bus masters. Doesn't even try. There came a time in the A3000 development where I had to chose between adding more Zorro III features (I designed the whole bus specification before I did the chip work) and getting Zorro II compatibility up to par. Zorro II was tricky -- in essence, it's a 68000 bus emulator in there, and some of the interactions between 68K procotol and real Zorro II hardware were not things you could have easily predicted at the start of the project. And given that C= management hadn't even asked for expansion bus improvements on the A3000 (all my idea), you can see where Level I came from. The Level II part (about twice as many gates) was out in two revisions; Rev 9, which initially shipped with the A4000, and Rev 11, which is the best you'll ever get. The Rev 9 part has two bugs that can cause problems with Zorro III cards. One can affect some kinds of bus slave cards, it depends on the card design. This is due to a small flaw in a synchronizer stage in the Level II chip (Level II runs a slightly faster bus protocol than Level I, and also supports burst). The other is a flaw in the Zorro III bus arbiter -- there's a small window in which a Zorro III slave cycle just starting can confuse a bus registration command, locking the bus. Rev 11 solves both problems, so you need it for DMA devices. The Rev 9 problems were fairly well qualified, so you have some devices that offered work-arounds. I didn't for the A4091 -- at the time, C= probably wouldn't have let me do the Rev 11 chip if the A4091 could have worked at all in existing A4000s. A3000s use the Level I Buster, never intended to work with something like the A4091. The Rev 11 part works fine in the A3000, and in fact fixed a race condition between Gary and the chip bus that can cause memory failured during Zorro II DMA to Chip RAM. The big problem with Buster testing was the lack of any Zorro III cards to test it with. Very early on, I did a memory card, which tested normal slave access and even supported burst, though I didn't have a Buster that did for a year after this. The next test board was done for the multiprocessor project. This "Gemini" board tested the remaining Level II features: bus arbitration, bus mastering, Quick Interrupts, etc. Unfortunately, I based it on the Buster chip (there's a secret mode in Buster Level II that lets it run as a card controller rather than a motherboard controller). But that year (1991), CSG was changing over from channelled gate arrays to sea-of-gates technology, and their first chips were running at 1/4 speed or so. Six months later, I had fast chips, but also the new Engineering Administration, which considered Gemini either an illegal research project, or "something from the last administration". So no big pounding on the Zorro III bus was possible before the A4000 shipped. In all fairness, the Zorro III project was a large thing to bite off. When The PC Industry made EISA, there were hundreds of people involved: some to hammer out the specs, some to make chips, test, etc. At Commodore, it was basically just me for most of the life of Zorro III. The A4091 doesn't work with Level I Buster. Also, if you have an older A4091, OS2.04 or SuperKickStart could prevent it from booting, it would require 3.0 or 3.1 ROMs. And, just as a technical detail, Zorro III doesn't use a clock. The Z3 timing is based on your motherboard clock, but the bus protocol itself is asynchronous.

Chip Name	Part Number	Used in
Buster 5721	318075-01	A2000
Buster 5731 Rev A	318075-02	A2000
Super Buster 71	390529-06	A3000
Super Buster 45	390537-09	A4000
Super Buster 71	390539-07	A3000
Super Buster 45	390539-09	A3000, A2631
Super Buster 45	390539-11	A4000, A4000T

 

"CIA"

The Amiga contains two CIA's, known as CIA-A and CIA-B although they are both the same chip. The CIA's are responsible for, or take part in various I/O functions such as the serial, parallel, joystick & mouse ports.

Chip Number	Part Number	Used In
8520A-1	318029-03	A2000
8520A-1		A1000
8520PL	391078-01	A600
8520A-1	391078-02
8520R2		A1000 NTSC

 

"Daphne"

Daphne was either a very early name for Denise, or an early version of what eventually became Denise. Very early versions of the A1000 shipped with the Daphne chip.

Chip Name	Chip Number	Part Number	Used In
Daphne (OCS)	8362 R5		A1000 NTSC, 1985
Daphne (OCS)	8362 R6		A1000, 1985

 

"Denise"

The Denise is responsible for handling most of the graphics related tasks, including the native screens and support for up to eight hardware sprites. It supports up to 32 colours per screen from a palette of 4096, or 4096 colours on screen in HAM-6 mode. Some versions of Denise (usually those in the ECS chipset) also support EHB mode (extra half-brite) which is up to 64 colours on screen, however the second 32 colours MUST be half the brightness of the first 32. Denise is the ECS & OCS chipset equivalent of Lisa, found in the AGA chipset.

Chip Name	Chip Number	Part Number	Used In
Denise (OCS)	8362 R6
Denise (OCS)	8362 R8
Super-Denise (ECS)	8373 R4	390433-02	A500+, A2000, A3000
Super-Denise (ECS)	8373 R4	391061-01	A600
Super-Denise (ECS)	8373 R4	391081-01	A600

 

"DMAC"

The DMAC controls part of the onboard SCSI found in the A3000 series machines, and the A4000T. DMAC 02 is usually used with Ramsey 04 and Dmac 04 is usually used with Ramsey 07. You can't mix them up.

Chip Name	Part Number	Used In
DMAC	390563-01	A590, A2091
DMAC	390563-02	A3000
DMAC	390563-04	A3000T, A4000T
Super DMAC 81	390537-02	A3000

 

"Gary"

The Gary chip isn't really much more than a gate array which contains some control logic for accessing certain busses. Only some models of Amiga contain a gary chip.

Name	Part Number	Used In
Gary (5718)	318072-01	A2000
Gary (5719)	318072-01	A500, A500+
Fat Gary 41 (4393)	390540-02	A3000, A4000
Fat Gary 41 (4791)	390540-02	A3000

 

"Gayle"

The Gayle chip is responsible for controlling the 2.5" non-buffered IDE controller found in the A600, A1200 and the 3.5" buffered IDE controller found in the A4000 and A4000T. The IDE controller is quite poor, particularly by today's standards, providing little more than PIO Mode 0.

Chip Name	Chip Number	Used In
45 Gayle	391155-01	A600
45 Gayle	391155-02	A600
AA Gayle R5	391155-02
AA Gayle R5	391424-02

 

"Kickstart"

The Kickstart chips are responsible for holding the core of the Amiga operating system, what you probably could loosely consider as the kernel. Depending on the machine you have the Kickstart is either held as 1 x 512K ROM or 2 x 256K ROMs. Some models of Amiga also accept a disk based version of Kickstart such as the A1000 and some A3000s.

Kickstart Version	Used In
1.4 (?????)	A3000
2.04 (V37.175)	A2000, A3000
2.05 (37.299)	A600
2.05 (37.300)	A600
2.05 (37.350)	A600HD
3.0 (39.105)	A4000
3.0 (39.106)	A1200, A4000
3.0 (39.405)	A4000
3.1 (40.68)	A500*, A600*, A2000*, A1200, A4000 (*=as an upgrade)
3.1 (40.70)	A4000T

 

"Lisa"

Lisa is primarily responsible for handling the graphics tasks, and has support for hardware sprites. Lisa can handle many video modes and resolutions supporting up to 256 colours per screen from a 24bit palette (including Extra Half-Brite), or with HAM-8 mode 262,144 colours on screen. Lisa is AGA's equivalent of Denise found in the OCS & ECS chipsets.

Chip Number	Part Number	Used In
LISA 1204 R0	391227-01	A4000
LISA 1207 R0	391227-01	AA3000
LISA 4203 R2	391227-01

 

"Paula"

Paula performs two main functions in the Amiga. Primarily it provides the Amiga's native audio which is 4 channel 8 bit sound, but it also functions as the floppy drive controller.

Chip	Chip Number	Used In
Paula 8364 R4		A1000
Paula 8364 R7	252127-02	A500+, A2000, A3000, AA3000
Paula 8364 R7	391077-01	A600, A4000

 

"Portia"

Portia was either a very early name for Paula, or a very early version of what eventually became Paula. Basically the sound chip and floppy drive controller. Early A1000's may have shipped with this chip, but this has not been confirmed. The very first Amiga ever, known as Lorraine contained a chip called Portia.

 

"Ramsey"

Found only in the A3000 series and A4000T machines, the Ramsey is responsible for addressing RAM and producing DMA addressing, particularly with regards to the motherboard SCSI controller. Ramsey 04 is normally used with DMac 02, and Ramsey 07 is normally used with Dmac 04.

Chip Number	Part Number	Used in
Ramsey	390398-01	A590, A2091
Ramsey 51	390541-04	A3000, A4000
Ramsey 45	390541-07	A3000T, A4000, A4000T

 

"Toni"

Toni was a custom chip only ever used in the unreleased Amiga Walker. Toni was the system bus controller, including the DRAM interface. It may also have been responsible for controlling the FIDO serial ports and other I/O.