82801DB Datasheet, PDF (138/587 Pages) Intel Corporation – Intel 82801DB I/O Controller Hub 4 (ICH4)

Functional Description
Table 5-38 shows which events can cause an SMI# and SCI. Note that some events can be
programmed to cause either an SMI# or SCI. The usage of the event for SCI (instead of SMI#) is
typically associated with an ACPI-based system. Each SMI# or SCI source has a corresponding
enable and status bit.
Table 5-38. Causes of SMI# and SCI (Sheet 1 of 2)
Cause
SCI SMI
PME#
Yes Yes
PME_B0 (internal EHCI controller) Yes Yes
Power Button Press
Yes Yes
RTC Alarm
Yes Yes
Ring Indicate
Yes Yes
AC ’97 wakes
Yes Yes
USB UHCI #1 wakes
Yes Yes
USB UHCI #2 wakes
Yes Yes
USB UHCI #3 wakes
Yes Yes
THRM# pin active
Yes Yes
ACPI Timer overflow (2.34 sec.)
Yes Yes
Any GPI
Yes Yes
TCO SCI Logic
Yes No
TCO SCI message from MCH
Yes No
TCO SMI Logic
No Yes
TCO SMI -Year 2000 Rollover
No Yes
TCO SMI -TCO TIMEROUT
No Yes
TCO SMI - OS writes to
TCO_DAT_IN register
No Yes
TCO SMI -Message from MCH
No Yes
TCO SMI - NMI occurred (and
NMIs mapped to SMI)
No Yes
TCO SMI -INTRUDER# signal
goes active
No Yes
TCO SMI - Change of the BIOSWP
bit from 0 to 1
No
Yes
TCO SMI -Write attempted to BIOS No Yes
BIOS_RLS written to
Yes No
GBL_RLS written to
No Yes
Write to B2h register
No Yes
Periodic timer expires
No Yes
64 ms timer expires
No Yes
Enhanced USB Legacy Support
Event
No Yes
Enhanced USB Intel Specific Event No Yes
Classic USB Legacy logic
No Yes
Serial IRQ SMI reported
No Yes
Additional Enables
PME_EN=1
PME_B0_EN=1
PWRBTN_EN=1
RTC_EN=1
RI_EN=1
AC ’97_EN=1
USB1_EN=1
USB2_EN=1
USB3_EN=1
THRM_EN=1
TMROF_EN=1
GPI[x]_Route=10 (SCI)
GPI[x]_Route=01 (SMI)
GPE0[x]_EN=1
TCOSCI_EN=1
none
TCO_EN=1
none
none
none
none
NMI2SMI_EN=1
INTRD_SEL=10
BLD=1
BIOSWP=1
GBL_EN=1
BIOS_EN=1
none
PERIODIC_EN=1
SWSMI_TMR_EN=1
LEGACY_USB2_EN = 1
INTEL_USB2_EN = 1
LEGACY_USB_EN=1
none
Where Reported
PME_STS
PME_B0_STS
PWRBTN_STS
RTC_STS
RI_STS
AC ’97_STS
USB1_STS
USB2_STS
USB3_STS
THRM_STS
TMROF_STS
GPI[x]_STS
GPE0_STS
TCOSCI_STS
MCHSCI_STS
TCO_STS
NEWCENTURY_STS
TIMEOUT
OS_TCO_SMI
MCHSMI_STS
NMI2SMI_STS
INTRD_DET
BIOSWR_STS
BIOSWR_STS
GBL_STS
BIOS_STS
APM_STS
PERIODIC_STS
SWSMI_TMR_STS
LEGACY_USB2_STS
INTEL_USB2_STS
LEGACY_USB_STS
SERIRQ_SMI_STS
138
Intel^® 82801DB ICH4 Datasheet