PRELIMINARY
103
A
82453KX/GX, 82452KX/GX, 82451KX/GX (MC)
2.2.1
CONFADD—CONFIGURATION ADDRESS REGISTER
Address Offset:
0CF8h (Dword access only)
Default:
00000000h
Attribute:
Write Only
The CONFADD Register contains the Bus Number, Device Number, Function Number, and Register Number
for which a subsequent configuration access is intended. For example, a write of 8000A0ACh to the CONFADD
register can be used to access the 82453KX Memory Timing Register.
2.2.2
CONFDATA—CONFIGURATION DATA REGISTER
Address Offset:
0CFCh
Default:
00000000h
Attribute:
Read/Write
CONFDATA is a 32-bit read/write window into configuration space. The portion of configuration space that is
reference by CONFDATA is determined by the contents of CONFADD. The BE signals determine which bytes
get written..
Bits
Description
31
Configuration Enable (CSE). 1=Enable. 0=Disable.
30:24
Reserved. Write 0’s.
23:16
Bus Number (BUSNUM). The MC bus number is 00h.
15:11
Device Number (DEVNUM). The device number is reported in the CDNUM Register (offset 49h).
450KX: DEVNUM=10100 (hardwired)
450GX: The device number for an MC is determined at power-up and is reported in the CDNUM
Register (offset 49h). DEVNUM=10100, or 10101 (depends on OMCNUM signal strapping).
10:8
Function Number (FUNCNUM). The MC responds to configuration cycles with a function number of
000b. All other function number values attempting access to the MC (BUSNUM=00h and DEVNUM
matching MC device number) are ignored by the MC.
7:2
Register Number (REGNUM). This field selects one register within MC, if the MC configuration
space is selected by the other fields in the CONFADD Register.
1:0
Reserved. Write 0’s.
Bits
Description
31:0
Configuration Data Window. If bit 31 of CONFADD=1, an access to CONFDATA
I/O space is mapped to configuration space using the contents of CONFADD.