BMC Functional Specifications ESB2 BMC Core TPS
Revision 1.0
Intel order number E18291-001
268
DC power-on and system resets do not re-arm processor status sensors.
22.15.1.1 Processor Presence
When the BMC detects an empty processor socket, it sets the disable bit in the processor status
for that socket and clears the remaining status bits, including any persistent bits.
Upon BMC initialization, the processor presence offset is initialized to the de-asserted state.
The BMC then checks to see if the processor is present, setting the offset accordingly. This
state is updated at each DC power-on and at system resets. The net effect is that there should
be one event logged for processor presence at BMC initialization for each installed processor,
assuming the SDR is configured to generate the event. No additional events for processor
presence are expected unless the sensor is manually re-armed using an IPMI command.
22.15.1.2 Thermtrip Monitoring
The BMC retains ThermTrip history for each processor. This history tracks whether the
processor has had a ThermTrip since the last processor sensor re-arm or retest.
When a ThermTrip occurs, the BMC polls the ThermTrip status for each processor and then the
system begins the power down sequence. If the BMC detects that a ThermTrip occurred, then it
sets the ThermTrip offset for the applicable processor status sensor.
22.15.1.3 IERR Monitoring
The BMC monitors the internal error (IERR) signal from each processor and maps it to the IERR
offset of the associated processor status sensor.
22.15.2 Processor VRD Over-Temperature Sensor
This sensor monitors a signal that indicates whether a processor VRD is running over
temperature. The state of this signal is not an input into the system fan control sub-
system, but it is an input into the LM94* devices, which asserts the associated Prochot
signal and lowers the VRD temperature. This relationship is 1:1: if VRD-hot is asserted,
then Prochot asserts.
The Prochot assertion will affect the reading of the associated Prochot sensor and may
result in additional SEL events being logged.
22.15.3 Digital Thermal Sensor
The Quad-Core Intel® Xeon® Processors 7300 Series or Dual-Core Intel Xeon Processors
7200 Series supports a digital thermal sensor that provides a relative temperature reading that
is defined as the number of degrees below the processor’s thermal throttling trip point, also
called the PROCHOT threshold. When a processor reaches this temperature, the processor’s
PROCHOT signal asserts, indicating that one or more of the processor’s built-in thermal control
circuits (TCC) has activated to limit further increases in temperature by throttling the processor.
The digital thermal sensor reading value is always less than or equal to zero. A reading of zero
indicates that the PROCHOT threshold has been reached. The reading remains at zero until the
temperature goes back below the PROCHOT threshold.
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