Intel® Server Boards SE7320SP2 and SE7525GP2
Functional Architecture
Revision 4.0
53
3.7.3.1 CONFIG_ADDRESS
Register
CONFIG_ADDRESS is 32 bits wide and contains the field format shown in the following figure.
Bits [23::16] choose a specific bus in the system. Bits [15::11] choose a specific device on the
selected bus. Bits [10:8] choose a specific function in a multi-function device. Bit [8::2] select a
specific register in the configuration space of the selected device or function on the bus.
Figure 12. CONFIG_ADDRES Register
3.7.3.1.1 Bus
Number
PCI configuration space protocol requires that all PCI buses in a system be assigned a Bus
Number, Furthermore, bus numbers must be assigned in ascending order within hierarchical
buses. Each PCI bridge has registers containing its PCI Bus Number and subordinate PCI Bus
Number, which must be loaded by POST code. The Subordinate PCI Bus Number is the bus
number of the last hierarchical PCI bus under the current bridge. The PCI Bus Number and the
Subordinate PCI Bus Number are the same in the last hierarchical bridge.
3.7.3.1.2
Device Number and IDSEL Mapping
Each device under a PCI bridge has its IDSEL input connected to one bit out of the PCI bus
address/data signals AD[31::11] for the PCI bus. Each IDSEL-mapped AD bit acts as a chip
select for each device on PCI. The host bridge responds to a unique PCI device ID value, that
along with the bus number, cause the assertion of IDSEL for a particular device during
configuration cycles. The following table shows the correspondence between IDSEL values and
PCI device numbers for the PCI bus. The lower 5-bits of the device number are used in
CONFIG_ADDRESS bits [15::11].
Table 19. PCI Configuration IDs and Device Numbers
PCI Device
IDSEL
Bus# / Device# / Function#
MCH host-HI bridge/DRAM controller
00 / 00 / 0
MCH DRAM Controller Error Reporting
00/00/1
MCH DMA controller
00/01/00
MCH EXP Bridge A0
00/02/00
0
0
Register
0
1
7
8
10
11
15
16
23
24
30
31
Function
Device
Bus Number
Reserved
Enable bit (‘1’ = enabled, ‘0’ = disabled)
Summary of Contents for SE7320SP2 - 800MHZ Ecc Ddr Xeon
Page 182: ......