Intel Video Game Controller Intel Gigabit Ethernet Controllers User Manual

Page of 406
134
Software Developer’s Manual
Power Management
6.3.2.2
Transition From D0a to D3 and Back Without PCI Reset 
Figure 6-3. Transition from D0a to D3 and Back Without PCI Reset
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Diagram #
Notes
1
Writing a 11b to the Power State field of the Power Management Control/Status Register (PMCSR) transitions 
the Ethernet controller to D3.
2
The system can keep the Ethernet controller in D3 state for an arbitrary amount of time.
3
To exit D3 state the system writes 00b to the Power State field of the Power Management Control/Status 
Register (PMCSR).
4
APM Wakeup mode can be enabled based on what is read in the EEPROM.
5
For the 82544GC/EI, PWR_STATE[1:0] is set to 01b if APM Wakeup is enabled, 00b otherwise.
6
The system can delay an arbitrary time before enabling memory access.
7
Writing a 1b to the Memory Access Enable or I/O Access Enable bit in the PCI Command Register transitions 
the Ethernet controller from D0u to D0 state.
For the 82544GC/EI, writing a 1b to the Memory Access Enable or I/O Access Enable bit in the PCI Command 
Register transitions the Ethernet controller from D0u to D0 state and asserts both PWR_STATE outputs.