Specifications
A–4 System Address Mapping
Subject to Change – 17 January 1997
21164 Address Space Configuration Supported by the CIA
A.2.1 21164 Access to Address Space
The 21164 microprocessor has access to the complete address space. It can access
cached memory and CSRs, as well as all the PCI memory, I/O, and configuration
regions, as shown in Figure A–3.
Figure A–3 Address Space Overview
A.2.2 PCI Access to Address Space
PCI devices have a restricted view of the address space. They can access any PCI
device through the PCI memory or PCI I/O space, but they have no access to PCI
configuration space.
Furthermore, the CIA restricts PCI access to the system memory (for DMA
operations) through five programmable address windows in PCI memory space, as
shown in Figure A–3.
21164
Environment
Main System
Memory
PCI
Memory Space
PCI Window
PCI I/O Space
PCI
Device
PCI
Configuration
Space
CSRs
PCI
Device
21164
LJ-04261.AI