Intel i5-2500K BX80623I52500K User Manual

Datasheet, Volume 1

65

Signal Description

CATERR#

Catastrophic Error: This signal indicates that the system has 

experienced a catastrophic error and cannot continue to operate. The 

processor will set this for non-recoverable machine check errors or 

other unrecoverable internal errors. 
On the processor, CATERR# is used for signaling the following types of 

errors:

• Legacy MCERRs – CATERR# isasserted for 16 BCLKs.
• Legacy IERRs – CATERR# remains asserted until warm or cold 

reset.

O

CMOS

PECI

PECI (Platform Environment Control Interface): A serial sideband 

interface to the processor, it is used primarily for thermal, power, and 

error management. 

I/O

Asynchronous

PROCHOT#

Processor Hot: PROCHOT# goes active when the processor 

temperature monitoring sensor(s) detects that the processor has 

reached its maximum safe operating temperature. This indicates that 

the processor Thermal Control Circuit (TCC) has been activated, if 

enabled. This signal can also be driven to the processor to activate the 

TCC.

CMOS Input/

Open-Drain 

Output

THERMTRIP#

Thermal Trip: The processor protects itself from catastrophic 

overheating by use of an internal thermal sensor. This sensor is set 

well above the normal operating temperature to ensure that there are 

no false trips. The processor will stop all execution when the junction 

temperature exceeds approximately 130 °C. This is signaled to the 

system by the THERMTRIP# pin. 

O

Asynchronous 

CMOS

SM_DRAMPWROK

SM_DRAMPWROK Processor Input: Connects to PCH 

DRAMPWROK. 

I

Asynchronous

CMOS

UNCOREPWRGOOD

The processor requires this input signal to be a clean indication that 

the V

CCSA

, V

CCIO

, V

AXG

, and V

DDQ

, power supplies are stable and 

within specifications. This requirement applies, regardless of the S-

state of the processor. 'Clean' implies that the signal will remain low 

(capable of sinking leakage current), without glitches, from the time 

that the power supplies are turned on until they come within 

specification. The signal must then transition monotonically to a high 

state. This is connected to the PCH PROCPWRGD signal.

I

Asynchronous 

CMOS

SKTOCC# 

SKTOCC# (Socket Occupied): Pulled down directly (0 Ohms) on 

the processor package to ground. There is no connection to the 

processor silicon for this signal. System board designers may use this 

signal to determine if the processor is present.