Serial and Parallel ATA Drive Guidelines and Features

4.8.1 Legacy Mode

The Legacy mode is used to access devices attached to an embedded ATA controller. Each channel of the controller requires two fixed I/O address ranges and an IRQ.

■Primary Channel

❏Command block: 1F0h - 1F7h

❏Control block: 3F6h

❏IRQ: 14

■Secondary Channel

❏Command block: 170h - 177h

❏Control block: 376h

❏IRQ: 15

4.8.2Native Mode

The native mode is used to access devices attached to additional ATA controllers and is not supported by many legacy operating systems. Addresses are assigned by PCI Plug-n-Play BIOS and the IRQ is shared with multiple controllers. Base Address Registers for the Command and Control Block are found in the PCI Configuration Space.

■Offset 10h—Primary Command base address

■Offset 14h—Primary Control base address

■Offset 18h—Secondary Command base address

■Offset 1Ch—Secondary Control base address

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Service Reference Guide, dc7600