FW82801DB S L66K Intel, FW82801DB S L66K Datasheet - Page 47

• Manufacturer Part Number: FW82801DB S L66K
• Manufacturer: Intel

Specifications of FW82801DB S L66K

• Lead Free Status / RoHS Status: Supplier Unconfirmed

2.11
Intel
®
Table 2-11. Processor Interface Signals (Sheet 1 of 2)
82801DB ICH4 Datasheet
Processor Interface
CPUSLP#
STPCLK#
IGNNE#
FERR#
A20M#
Name
INIT#
INTR
SMI#
NMI
Type
O
O
O
O
O
O
O
O
I
Mask A20: A20M# will go active based on either setting the appropriate bit in
the Port 92h register, or based on the A20GATE input being active.
Speed Strap: During the reset sequence, Intel
corresponding bit is set in the FREQ_STRP register.
CPU Sleep: This signal puts the processor into a state that saves substantial
power compared to Stop-Grant state. However, during that time, no snoops
occur. The ICH4 can optionally assert the CPUSLP# signal when going to the
S1 state.
Numeric Coprocessor Error: This signal is tied to the coprocessor error
signal on the processor. FERR# is only used if the ICH4 coprocessor error
reporting function is enabled in the General Control Register (Device
31:Function 0, Offset D0, bit 13). If FERR# is asserted, the ICH4 generates an
internal IRQ13 to its interrupt controller unit. It is also used to gate the IGNNE#
signal to ensure that IGNNE# is not asserted to the processor unless FERR# is
active. FERR# requires an external weak pull-up to ensure a high level when
the coprocessor error function is disabled.
NOTE: FERR# can be used in some states for notification by the processor of
Ignore Numeric Error: This signal is connected to the ignore error pin on the
processor. IGNNE# is only used if the ICH4 coprocessor error reporting
function is enabled in the General Control Register (Device 31:Function 0,
Offset D0,
bit 13). If FERR# is active, indicating a coprocessor error, a write to the
Coprocessor Error Register (F0h) causes the IGNNE# to be asserted. IGNNE#
remains asserted until FERR# is negated. If FERR# is not asserted when the
Coprocessor Error Register is written, the IGNNE# signal is not asserted.
Speed Strap: During the reset sequence, ICH4 drives IGNNE# high if the
corresponding bit is set in the FREQ_STRP register.
Initialization: INIT# is asserted by the ICH4 for 16 PCI clocks to reset the
processor. ICH4 can be configured to support CPU BIST. In that case, INIT#
will be active when PCIRST# is active.
CPU Interrupt: INTR is asserted by the ICH4 to signal the processor that an
interrupt request is pending and needs to be serviced. It is an asynchronous
output and normally driven low.
Speed Strap: During the reset sequence, ICH4 drives INTR high if the
corresponding bit is set in the FREQ_STRP register.
Non-Maskable Interrupt: NMI is used to force a non-Maskable interrupt to the
processor. The ICH4 can generate an NMI when either SERR# or IOCHK# is
asserted. The processor detects an NMI when it detects a rising edge on NMI.
NMI is reset by setting the corresponding NMI source enable/disable bit in the
NMI Status and Control Register.
Speed Strap: During the reset sequence, ICH4 drives NMI high if the
corresponding bit is set in the FREQ_STRP register.
System Management Interrupt: SMI# is an active low output synchronous to
PCICLK. It is asserted by the ICH4 in response to one of many enabled
hardware or software events.
Stop Clock Request: STPCLK# is an active low output synchronous to
PCICLK. It is asserted by the ICH4 in response to one of many hardware or
software events. When the processor samples STPCLK# asserted, it responds
by stopping its internal clock.
pending interrupt events. This functionality is independent of the
General Control Register bit setting.
Description
®
ICH4 drives A20M# high if the
Signal Description
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