Intel X5472 Data Sheet - Page 94

THERMTRIP# Signal, Introduction

Page 94 highlights

Thermal Specifications 6.2.5 THERMTRIP# Signal Regardless of whether or not Intel® Thermal Monitor 1 or Intel® Thermal Monitor 2 is enabled, in the event of a catastrophic cooling failure, the processor will automatically shut down when the silicon has reached an elevated temperature (refer to the THERMTRIP# definition in Table 5-1). At this point, the FSB signal THERMTRIP# will go active and stay active as described in Table 5-1. THERMTRIP# activation is independent of processor activity and does not generate any bus cycles. Intel also recommends the removal of VTT. 6.3 Platform Environment Control Interface (PECI) 6.3.1 Introduction PECI offers an interface for thermal monitoring of Intel processor and chipset components. It uses a single wire, thus alleviating routing congestion issues. Figure 6-8 shows an example of the PECI topology in a system with Quad-Core Intel® Xeon® Processor 5400 Series. PECI uses CRC checking on the host side to ensure reliable transfers between the host and client devices. Also, data transfer speeds across the PECI interface are negotiable within a wide range (2Kbps to 2Mbps). The PECI interface on the Quad-Core Intel® Xeon® Processor 5400 Series is disabled by default and must be enabled through BIOS. Figure 6-8. Quad-Core Intel® Xeon® Processor 5400 Series PECI Topology P ro c es s o r (Socket 0) 0 x 3 D om ain0 G5 0 0 x 3 D om ain1 0 PECI Host C ontroller P ro c es s o r (Socket 1) 0 x 3 D om ain0 1 G5 0 x 3 D om ain1 1 6.3.1.1 TCONTROL and TCC Activation on PECI-based Systems Fan speed control solutions based on PECI utilize a TCONTROL value stored in the processor IA32_TEMPERATURE_TARGET MSR. The TCONTROL MSR uses the same offset temperature format as PECI though it contains no sign bit. Thermal management devices should infer the TCONTROL value as negative. Thermal management algorithms 94

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Thermal Specifications
94
6.2.5
THERMTRIP# Signal
Regardless of whether or not Intel® Thermal Monitor 1 or Intel® Thermal Monitor 2 is
enabled, in the event of a catastrophic cooling failure, the processor will automatically
shut down when the silicon has reached an elevated temperature (refer to the
THERMTRIP# definition in
Table 5-1
). At this point, the FSB signal THERMTRIP# will go
active and stay active as described in
Table 5-1
. THERMTRIP# activation is independent
of processor activity and does not generate any bus cycles. Intel also recommends the
removal of V
TT
.
6.3
Platform Environment Control Interface (PECI)
6.3.1
Introduction
PECI offers an interface for thermal monitoring of Intel processor and chipset
components. It uses a single wire, thus alleviating routing congestion issues.
Figure 6-8
shows an example of the PECI topology in a system with Quad-Core Intel®
Xeon® Processor 5400 Series. PECI uses CRC checking on the host side to ensure
reliable transfers between the host and client devices. Also, data transfer speeds across
the PECI interface are negotiable within a wide range (2Kbps to 2Mbps). The PECI
interface on the Quad-Core Intel® Xeon® Processor 5400 Series is disabled by default
and must be enabled through BIOS.
6.3.1.1
T
CONTROL
and TCC Activation on PECI-based Systems
Fan speed control solutions based on PECI utilize a T
CONTROL
value stored in the
processor IA32_TEMPERATURE_TARGET MSR. The T
CONTROL
MSR uses the same offset
temperature format as PECI though it contains no sign bit. Thermal management
devices should infer the T
CONTROL
value as negative. Thermal management algorithms
Figure 6-8.
Quad-Core Intel® Xeon® Processor 5400 Series PECI Topology
PECI Host
Controller
Domain0
0
x
3
0
Domain1
0
x
3
0
Domain0
0
x
3
1
Domain1
0
x
3
1
Processor
(Socket 0)
Processor
(Socket 1)
G5
G5