Intel E7520 PCI PM Support, Platform Management, System Fan Operation, Wake from S5 State

Dual-Core Intel Xeon processor LV / E7520 Chipset / 6300ESB ICH

4.2.10Wake from S5 State

The power button is used to wake from S5.

4.3PCI PM Support

This design holds the system reset signal low when in a sleep state. The system supports the PCI PME# signal and provides 3.3 V standby to the PCI and PCI Express slots. This support allows any compliant PCI or PCI Express card to wake up the system from any sleep state except mechanical off. Because of the limited amount of power available on 3.3 V standby, the user and the operating system must configure the system carefully following the PCI power management interface specification.

4.4Platform Management

The LM 93 monitors the majority of the system voltages. The VID signals from the processors are also monitored by LM 93. All voltage levels can be read via the SMBus.

4.4.1Processor Thermal Management

Each processor monitors its own core temperature and thermally manages itself when it reaches a certain temperature. The system also uses the internal processor diode to monitor the die temperature. The diode pins are routed to the diode input pins in the LM 93. The LM 93 can be programmed to force the processor fans to full speed operation when it senses the processor core temperature exceeding a specific value. In addition, the LM 93 has an on-chip thermal monitor which allows it to monitor the incoming ambient temperature. Additional processor thermal management requires the system to communicate to the processors when the VRD reaches a critical temperature. The VR thermal monitor asserts FORCEPR_N signal to the processor.

4.5System Fan Operation

The system uses both the LM 93 and SMSC LPC47M172 to monitor and control the fans in the system.The LM93 uses pulse width modulated (PWM) outputs that can modulate the voltage across the fans, providing a variable duty cycle to effect a reduced DC voltage from nominal 12V DC.

By default, the CPU fans are jumpered to run at full speed all the time. The fan headers are the standard 12 V, three-pin type used in previous servers, which support tachometer out. The LM 93 also has four tachometer inputs that it can use to monitor the fans it controls. All fan tachometer data can be extracted from the controllers via the SMBus. The system fan speed control circuit does not control the power supply fan.

Each PWM output has a bypass jumper that causes all fans to run at full speed and ignore the PWM control. Each processor fan has its own dedicated PWM output and tachometer input, so each fan is controlled and monitored independently, depending on the core temperature.

The LM 93 is dedicated to processor fan speed control and monitor, and can be programmed with temperature limit values that allow it to speed up or idle the processor fans, depending upon the input temperature.

	Dual-Core Intel® Xeon® processor LV with Intel® E7520 Chipset and Intel® 6300ESB ICH
April 2007	User’s Manual
Order Number: 311274-009	39