Intel Celeron Processor on 0.13 Micron Process in the 478-Pin Package Datasheet

Intel

Celeron

Processor on 0.13 Micron Process in the 478-Pin Package Datasheet 79

Pin Listing and Signal Definitions

TRST# Input

TRST# (Test Reset) resets the Test Access Port (TAP) logic. TRST# must be

driven low during power on Reset. This can be done with a 680 Ω pull-down

resistor.

VCCA Input

VCCA provides isolated power for the internal processor core PLLs. Refer to

Table 1 for the appropriate Platform Design Guide for details on implementation.

VCCIOPLL Input

VCCIOPLL

provides isolated power for internal processor system bus PLLs.

Follow the guidelines for VCCA, and refer to the appropriate Platform Design

Guide for details on implementation.

VCC_SENSE Output

VCC_SENSE is an isolated low impedance connection to processor core power

(VCC). It can be used to sense or measure power near the silicon with little

noise.

VCCVID Input

An independent 1.2 V supply must be routed to VCCVID pin for the Celeron

processor on 0.13 micron process Voltage Identification circuit.

VID[4:0] Output

VID[4:0] (Voltage ID) pins are used to support automatic selection of power

supply voltages (VCC). Unlike previous generations of processors, these are

open drain signals that are driven by the Celeron processor on 0.13 micron

process and must be pulled up to 3.3 V (max.) with 1 kΩ resistors. The voltage

supply for these pins must be valid before the VR can supply VCC to the

processor. Conversely, the VR output must be disabled until the voltage supply

for the VID pins becomes valid. The VID pins are needed to support the

processor voltage specification variations. See Table 3 for definitions of these

pins. The VR must supply the voltage that is requested by the pins, or disable

itself.

VSSA Input VSSA is the isolated ground for internal PLLs.

VSS_SENSE Output

VSS_SENSE is an isolated low impedance connection to processor core VSS. It

can be used to sense or measure ground near the silicon with little noise.

Table 36. Signal Description (Sheet 8 of 8)

Name Type Description