Signal Description

3.0Signal Description

This section describes the Intel® 82854 GMCH signals. These signals are arranged in functional groups according to their associated interface. The following notations are used to describe the signal type.

Notation

Description

 

 

I

Input pin

 

 

O

Output pin

 

 

I/O

Bi-directional Input/Output pin

 

 

The signal description also includes the type of buffer used for the particular signal:

Buffer

Description

 

 

AGTL+

Open Drain AGTL+ interface signal. Refer to the AGTL+ I/O

 

Specification for complete details. The GMCH integrates AGTL+

 

termination resistors, and supports VTTLF of 1.05 V ± 5%. AGTL+

 

signals are "inverted bus" style where a low voltage represents a

 

logical 1.

 

 

DVO

DVO buffers (1.5-V tolerant)

 

 

Hub

Compatible to Hub interface 1.5

 

 

SSTL_2

Stub Series Termination Logic compatible signals (2.5-V tolerant)

 

 

LVTTL

Low Voltage TTL compatible signals (3.3-V tolerant)

 

 

CMOS

CMOS buffers (3.3-V tolerant)

 

 

Analog

Analog signal interface

 

 

Ref

Voltage reference signal

 

 

Note: System Address and Data Bus signals are logically inverted signals. In other words, the actual values are inverted from what appears on the system bus. This must be taken into account and the addresses and data bus signals must be inverted inside the GMCH. All processor control signals follow normal convention: A 0 indicates an active level (low voltage), and a 1 indicates an active level (high voltage).

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Intel D15343-003 manual Notation Description, Buffer Description