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The Amiga's Custom Chips - AGA

The Advanced Graphic Architecture Chip Set (AGA) was used for all of the fourth generation machines, i.e the A1200, A4000, A4000T and CD32.

It consisted of three main chips, Alice, Lisa and Paula.

Alice The custom chip used to control and move data to be displayed on the screen for Amigas fitted with the AGA chipset. It is also responsible for timing the machine and even directs animation. It replaced Agnus on earlier Amigas.
Lisa The custom chip that is responsible for the video output and is used to maintain the screen display on AGA chipset machines. It controls the resolution, colours, sprites, text lines, etc. Supercedes the DENISE chip on Amigas running the ECS chipset, and was to have superceded by the LINDA chip on Amigas running the AAA chipset.
Paula The custom chip responsible for all of the sounds generated from the Amiga. It provides four voices of sound output configured as two stereo channels with nine octaves over a range of complex waveforms, and uses both amplitude and frequency modulation. It also handles many of the input/ output tasks such as disk and interrupt control, the mouse, joystick and serial ports. This chip was to have been superceded by Mary in the AAA chipset.

Copyright 2005 Amiga Auckland Inc. All rights reserved.
Revised: September 25, 2005.