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