SQ575
16
Legacy ISA Devices compliant with the original PC AT bus specification, requiring a specific
DMA channel.
PCI/ISA PnP Devices compliant with the Plug and Play standard, whether designed for PCI
or ISA bus architecture.
4.7.6
PCI IDE IRQ Map To
This field lets you select PCI IDE IRQ mapping or PC AT (ISA) interrupts. If your system
does not have one or two PCI IDE connectors on the system board, select values according to
the type of IDE interface(s) installed in your system (PCI or ISA). Standard ISA interrupts for
IDE channels are IRQ14 for primary and IRQ15 for secondary.
4.7.7
Primary/Secondary IDE INT#
Each PCI peripheral connection is capable of activating up to four interrupts: INT# A, INT#
B, INT# C and INT# D. By default, a PCI connection is assigned INT# A. Assigning INT# B
has no meaning unless the peripheral device requires two interrupt services rather than just
one. Because the PCI IDE interface in the chipset has two channels, it requires two interrupt
services. The primary and secondary IDE INT# fields default to values appropriate for two
PCI IDE channels, with the primary PCI IDE channel having a lower interrupt than the
secondary.
4.8
