Datasheet

XIO2001

SCPS212G –MAY 2009–REVISED DECEMBER 2012

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Table 4-16. I/O Limit Upper 16-Bit Register Description

BIT FIELD NAME ACCESS DESCRIPTION

I/O limit upper 16 bits. Defines the upper 16 bits of the top address of the I/O address range that

15:0 IOLIMIT RW determines when to forward I/O transactions downstream. These bits correspond to address bits

[31:20] in the I/O address. The lower 20 bits are assumed to be FFFFFh.

4.26 Capabilities Pointer Register

This read-only register provides a pointer into the PCI configuration header where the PCI power

management block resides. Since the PCI power management registers begin at 40h, this register is

hardwired to 40h.

PCI register offset: 34h

Default value: 40h

BIT NUMBER 7 6 5 4 3 2 1 0

RESET STATE 0 1 0 0 0 0 0 0

4.27 Interrupt Line Register

This read/write register is programmed by the system and indicates to the software which interrupt line the

bridge has assigned to it. The default value of this register is FFh, indicating that an interrupt line has not

yet been assigned to the function. Since the bridge does not generate interrupts internally, this register is

a scratch pad register.

PCI register offset: 3Ch

Default value: FFh

BIT NUMBER 7 6 5 4 3 2 1 0

RESET STATE 1 1 1 1 1 1 1 1

4.28 Interrupt Pin Register

The interrupt pin register is read-only 00h indicating that the bridge does not generate internal interrupts.

While the bridge does not generate internal interrupts, it does forward interrupts from the secondary

interface to the primary interface.

PCI register offset: 3Dh

Default value: 00h

BIT NUMBER 7 6 5 4 3 2 1 0

RESET STATE 0 0 0 0 0 0 0 0

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