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I/O Device Controller

The I/O controller IC in the iMac family of computers is a custom IC called KeyLargo. It is an integrated I/O controller and DMA engine for use in Power Macintosh computers with a PCI bus.

The KeyLargo IC provides the interface and control signals for the following devices:

• the internal hard drive

• the CD-ROM or DVD-ROM drive

• the USB ports

• the built-in modem

• the sound codec IC

• the power manager IC

• the optional wireless LAN module

DMA Support

Interrupt Support

USB Interface

Ultra DMA Interface

Modem Support

Sound IC Support

Power Controller

Wireless LAN Module