82801BA Datasheet, PDF (221/498 Pages) Intel Corporation – Intel 82801BA I/O Controller Hub 2 (ICH2) and Intel 82801BAM I/O Controller Hub 2 Mobile

Register and Memory Mapping
6.3.1 Fixed I/O Address Ranges
Table 6-2 shows the fixed I/O decode ranges from the processor perspective. Note that for each I/O
range, there may be a separate behavior for reads and writes. The hub interface cycles that go to
target ranges that are marked as “Reserved” are not decoded by the ICH2; they are passed to PCI. If
a PCI master targets one of the fixed I/O target ranges, it will be positively decoded by the ICH2 in
Medium speed.
Refer to Table A-1 for a complete list of all fixed I/O registers. Address ranges that are not listed or
marked “Reserved” are NOT decoded by the ICH2 (unless assigned to one of the variable ranges).
Table 6-2. Fixed I/O Ranges Decoded by ICH2
I/O Address
Read Target
00h–08h
09h–0Eh
0Fh
10h–18h
19h–1Eh
1Fh
20h–21h
24h–25h
28h–29h
2Ch–2Dh
2Eh–2Fh
30h–31h
34h–35h
38h–39h
3Ch–3Dh
40h–42h
43h
4E–4F
50h–52h
53h
60h
61h
62h
63h
64h
65h
66h
67h
70h
71h
72h
73h
74h
DMA Controller
RESERVED
DMA Controller
DMA Controller
RESERVED
DMA Controller
Interrupt Controller
Interrupt Controller
Interrupt Controller
Interrupt Controller
LPC SIO
Interrupt Controller
Interrupt Controller
Interrupt Controller
Interrupt Controller
Timer/Counter
RESERVED
LPC SIO
Timer/Counter
RESERVED
Microcontroller
NMI Controller
Microcontroller
NMI Controller
Microcontroller
NMI Controller
Microcontroller
NMI Controller
RESERVED⁵
RTC Controller
RTC Controller
RTC Controller
RTC Controller
Write Target
DMA Controller
DMA Controller
DMA Controller
DMA Controller
DMA Controller
DMA Controller
Interrupt Controller
Interrupt Controller
Interrupt Controller
Interrupt Controller
LPC SIO
Interrupt Controller
Interrupt Controller
Interrupt Controller
Interrupt Controller
Timer/Counter
Timer/Counter
LPC SIO
Timer/Counter
Timer/Counter
Microcontroller
NMI Controller
Microcontroller
NMI Controller
Microcontroller
NMI Controller
Microcontroller
NMI Controller
NMI and RTC Controller
RTC Controller
NMI and RTC Controller
RTC Controller
NMI and RTC Controller
Internal Unit
DMA
DMA
DMA
DMA
DMA
DMA
Interrupt
Interrupt
Interrupt
Interrupt
Forwarded to LPC
Interrupt
Interrupt
Interrupt
Interrupt
PIT (8254)
PIT
Forwarded to LPC
PIT
PIT
Forwarded to LPC
processor I/F
Forwarded to LPC
processor I/F
Forwarded to LPC
processor I/F
Forwarded to LPC
processor I/F
RTC
RTC
RTC
RTC
RTC
82801BA ICH2 and 82801BAM ICH2-M Datasheet
6-3