Intel® ck-815 power gating on wake events, Intel, Ck-815 power gating on wake events – Intel 815 User Manual
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Intel
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815 Chipset Platform Design Guide
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11.7 Intel
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CK-815 Power Gating On Wake Events
For systems providing functionality with future 0.13 micron socket 370 processors, special
handling of wake events is required. When a wake event is triggered, the GMCH and the Intel CK-
815 must not sample BSEL[1:0] until the signal VTTPWRGD is asserted. This is handled by
setting up the following sequence of events:
1. Power is not connected to the Intel CK-815-compliant clock driver until VTTPWRGD12 is
asserted.
2. Clocks to the ICH stabilize before the power supply asserts PWROK to the ICH. There is no
guarantee this will occur as the implementation for the previous step relies on the 12V supply.
Thus, it is necessary to gate PWROK to the ICH from the power supply while the
Intel CK-815 is given sufficient time for the clocks to become stable. The amount of time
required is a minimum 20 ms.
3. ICH takes the GMCH out of reset.
4. GMCH samples BSEL[1:0]. Intel CK-815 will have sampled BSEL[1:0] much earlier.
Refer to Chapter 4 for full implementation details.