FW82801E Intel, FW82801E Datasheet - Page 49

• Manufacturer Part Number: FW82801E
• Description: Communications I/O Controller Hub
• Manufacturer: Intel

3.3
3.3.1
3.3.2
3.3.2.1
Advance Information Datasheet
Table 27. Functional Strap Definitions
Table 28. Test Mode Selection
Note: RTCRST# may be driven low any time after PCIRST is inactive. Refer to “Testability” on page 77
Pin Straps
Functional Straps
The following signals are used for static configuration. They are sampled at the rising edge of
PWROK to select configurations and then revert later to their normal usage. To invoke the
associated mode, the signal should be driven at least four PCI clocks prior to the time it is sampled.
Test Signals
Test Mode Selection
When PWROK is active (high), driving RTCRST# low for a number of PCI clocks (33 MHz) will
activate a particular test mode as specified in Table 28.
for a detailed description of the 82801E C-ICH test modes.
EE0_DOUT,
EE1_DOUT
Number of PCI Clocks RTCRST# driven low after PWROK active
HLCOMP
GNT[A]#
Signal
SPKR
Reserved
Top-Swap
Override
Enhanced
Hub
Interface
Mode
No Reboot
Usage
Rising
Edge of
PWROK
During
PCIRST#
assertion
Rising
Edge of
PWROK
Sampled
When
<4
4
5
6
7
System designers should include a placeholder for a pull-down
resistor on EE n _DOUT but do not populate the resistor .
The signal has a weak internal pull-up. If the signal is sampled low,
the system is strapped to the “Top-Swap” mode (82801E C-ICH will
invert A16 for all cycles targeting FWH BIOS space). The status of this
strap is readable via the Top-Swap bit (bit 13, D31: F0, Offset D4h).
Note that software will not be able to clear the Top-Swap bit until the
system is rebooted without GNT[A]# being pulled down.
If this signal is sampled high (via an external pull-up to VCC1_8), the
normal hub interface buffer mode will be selected. If this signal is
sampled low (via an external pull-down), the enhanced hub interface
buffer mode will be selected.
See the specific platform design guide for resistor values and routing
guidelines for each hub interface mode.
The signal has a weak internal pull-up. If the signal is sampled low,
the system is strapped to the “No Reboot” mode (82801E C-ICH will
disable the TCO Timer system reboot feature). The status of this strap
is readable via the NO_REBOOT bit (bit 1, D31: F0, Offset D4h).
Comment
No Test Mode Selected
XOR Chain 1
XOR Chain 2
XOR Chain 3
XOR Chain 4
Intel
Test Mode
®
82801E C-ICH
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