![](http://datasheet.mmic.net.cn/330000/INTEL82801_datasheet_16416407/INTEL82801_52.png)
Functional Description
5-2
82801AA and 82801AB Datasheet
5.1.3
IDSEL to Device Number Mapping
When addressing devices on the external PCI bus (with the PCI slots) the ICH asserts one address
signal as an IDSEL. When accessing device 0, the ICH asserts AD16. When accessing Device 1,
the ICH asserts AD17. This mapping continues all the way up to device 15 where the ICH asserts
AD31. Note that the ICH’s internal functions (AC’97, IDE, USB, and PCI Bridge) are enumerated
like they are on a separate PCI bus (the Hub Interface) from the external PCI bus.
5.1.4
SERR#/PERR#/NMI# Functionality
Figure 5-1
,
Figure 5-2
, and
Figure 5-3
show the logic used to generate/report SERR#, PERR#, and
NMI#. Note that PERR# is only on the ICH (82801AA).
There are several internal and external sources that can cause SERR#. The ICH can be
programmed to cause an NMI based on detecting that an SERR# condition has occurred. The NMI
can also be routed to instead cause an SMI#. Note that the ICH does not drive the external PCI bus
SERR# signal active onto the PCI bus. The external SERR# signal is an input into the ICH driven
only by external PCI devices.
The ICH (82801AA) can detect and report different parity errors in the system. The ICH can be
programmed to cause an NMI (or SMI# if NMI is routed to SMI#) based on detecting a parity error.
Figure 5-1. NMI# Generation Logic
AND
IOCHK From SERIRQ Logic
NMI_SC
[IOCHK_NMI_EN]
AND
To NMI#
Output
and
Gating
Logic
OR
NMI_SC
[IOCHK_NMI_STS]
AND
NMI_SC
[SERR#_NMI_STS]
NMI_SC
[PCI_SERR_EN]
OR
D30:F0 SECSTS
[SSE]
D30:F0 PDSTS
[SSE]
OR
AND
OR
TCO1_STS
[HCNMI_STS]
TCO1_CNT
[NMI_NOW]
NMI_EN
[NMI_EN]
D30:F0 PD_STS
[DPD]
D30:F0 SECSTS
[Data Parity Error
Detected]
PCI Parity Error detected
during AC'97, IDE or USB
Master Cycle
D30:F0 BRIDGE_CNT
[Parity Error Response
Enable]
AND
D31:F0 PCISTA
[DPED]
PCI Parity Error detected
during LPC or Legacy DMA
Master Cycle
D31:F0 PCICMD
[PER]
AND
Hub Interface Parity
Error Detected
D30:F0 CMD
[Parity Error Response]
ich_nmi.vsd
Note: Shaded area above is for ICH (82801AA) only