Datasheet

Datasheet 213
Host-Secondary PCI Express* Bridge Registers (D6:F0) (Intel
®
3210 MCH only)
8 Host-Secondary PCI Express*
Bridge Registers (D6:F0)
(Intel
®
3210 MCH only)
Note: The Device 6 register descriptions provided in this chapter applies only to the 3210
MCH in dual x8 mode.
Device 6 contains the controls associated with the PCI Express root port that is the
intended attach point for external devices. In addition, it also functions as the virtual
PCI-to-PCI bridge. The table below provides an address map of the D1:F0 registers
listed by address offset in ascending order. This chapter provides a detailed bit
description of the registers.
Warning: When reading the PCI Express "conceptual" registers such as this, you may not get a
valid value unless the register value is stable.
The PCI Express* Specification defines two types of reserved bits:
Reserved and Preserved:
• Reserved for future RW implementations; software must preserve value read for
writes to bits.
• Reserved and Zero: Reserved for future R/WC/S implementations; software must
use 0 for writes to bits.
Unless explicitly documented as Reserved and Zero, all bits marked as reserved are
part of the Reserved and Preserved type, which have historically been the typical
definition for Reserved.
Note: Most (if not all) control bits in this device cannot be modified unless the link is down.
Software is required to first disable the link, then program the registers, and then re-
enable the link (which will cause a full-retrain with the new settings).
Table 15. Host-Secondary PCI Express* Bridge Register Address Map (D6:F0) (Sheet 1
of 3)
Address
Offset
Register
Symbol
Register Name
Default
Value
Access
0–1h VID1 Vendor Identification 8086h RO
2–3h DID1 Device Identification 29F9h RO
4–5h PCICMD1 PCI Command 0000h RO, RW
6–7h PCISTS1 PCI Status 0010h RO, RWC
8h RID1 Revision Identification
See register
description
RO
9–Bh CC1 Class Code 060400h RO
Ch CL1 Cache Line Size 00h RW
Eh HDR1 Header Type 01h RO
18h PBUSN1 Primary Bus Number 00h RO
19h SBUSN1 Secondary Bus Number 00h RW