Agnus (Address GeNerator Unites)

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) 8372 318069-02 A500 (PAL), A2000 (PAL) Regular Type
Agnus (1MB) 8372A 318069-029 A500 (PAL), A2000 (PAL) (changed after some damage)
Agnus (2MB) 8372AB 318069-03 A3000 (PAL), A3000T (PAL) (came after 8375B)
Agnus (2MB) 8372B
Agnus (2MB) 8375 R0 318069-18 A500+ (PAL), A600 (PAL)
Agnus (1MB) 8375VBB / 8375 R1 318069-16 A500 (PAL), A2000 (PAL)
Agnus (2MB) 8375 R2 318069-10 A500+ (PAL), A600 (PAL)
Agnus (2MB) 8375 318069-11
Agnus (1MB) 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)

Thanks to Richard Wagenfuehrer, Joe Torre and Mathieu BUrgerhout