PCI Bridge
MPC8260 PowerQUICC II Family Reference Manual, Rev. 2
Freescale Semiconductor 9-43
in a PIBARx register causes a change in the GPLABARx in the base address bits that are non-masked by
PICMRx, and vice versa.
The system host is responsible for the configuration of the base address by writing to GPLABARx;
therefore, in PCI agent mode, the PIBARx registers should be read-only. However, if the PCI bridge is
defined as the PCI host, it may be easier to configure its own inbound base address by writing directly to
the PIBARx registers.
Figure 9-30. PCI Inbound Base Address Registers (PIBAR
x
)
Table9-17. describes PIBARx.
9.11.1.17 PCI Inbound Comparison Mask Registers (PICMR
x
)
The PCI inbound comparison mask registers (PICMRx), shown in Figure 9-31, defines the inbound
window’s size. In PCI agent mode, this register should be initialized (either by the core or by the CP’s
automatic EPROM load) before the AGENT_CFG_LOCK bit (see Section 9.11.2.22, “PCI Bus Function
Register”) can be cleared to enable the host to configure the device. Some of the fields of this registers are
tied to the GPLABARx registers; see Section 9.11.2.14, “General Purpose Local Access Base Address
Registers (GPLABARx) .
31 20 19 16
Field — BA
Reset 0000_0000_0000_0000
R/W R/W
Addr 0x108F2 (PITAR0); 0x108DA (PITAR0)
15 0
Field BA
Reset 0000_0000_0000_0000
R/W R/W
Addr 0x108F0 (PITAR0); 0x108D8 (PITAR0)
Table9-17. PIBAR
x
Field Descriptions
Bits Name Description
31–20 Reserved, should be cleared.
19–0 Base Address PCI address which is the starting point for the inbound translation window.This
corresponds to bits 31-12 of a 32-bit address