User's Manual

Advanced System Bus Design
3-2 Intel
®
820 Chipset Design Guide
Cross-talk The reception on a victim network of a signal imposed by aggressor network(s)
through inductive and capacitive coupling between the networks.
•
Backward Cross-talk - coupling which creates a signal in a victim network
that travels in the opposite direction as the aggressor’s signal.
•
Forward Cross-talk - coupling which creates a signal in a victim network
that travels in the same direction as the aggressor’s signal.
•
Even Mode Cross-talk - coupling from multiple aggressors when all the
aggressors switch in the same direction that the victim is switching.
•
Odd Mode Cross-talk - coupling from multiple aggressors when all the
aggressors switch in the opposite direction that the victim is switching.
Edge Finger The cartridge electrical contact that interfaces to the SC242 connector.
Flight Time Flight Time is a term in the timing equation that includes the signal propagation
delay, any effects the system has on the T
CO
of the driver, plus any adjustments
to the signal at the receiver needed to guarantee the setup time of the receiver.
More precisely, flight time is defined to be:
•
The time difference between a signal at the input pin of a receiving agent
crossing V
REF
(adjusted to meet the receiver manufacturer’s conditions
required for AC timing specifications; i.e., ringback, etc.), and the output
pin of the driving agent crossing V
REF
if the driver was driving the Test
Load used to specify the driver’s AC timings.
See Section for details regarding flight time simulation and validation.
The V
REF
Guardband takes into account sources of noise that may affect the
way an AGTL+ signal becomes valid at the receiver. See the definition of
the V
REF
Guardband.
•
Maximum and Minimum Flight Time - Flight time variations can be
caused by many different parameters. The more obvious causes include
variation of the board dielectric constant, changes in load condition, cross-
talk, V
TT
noise, V
REF
noise, variation in termination resistance and
differences in I/O buffer performance as a function of temperature, voltage
and manufacturing process. Some less obvious causes include effects of
Simultaneous Switching Output (SSO) and packaging effects.
•
The Maximum Flight Time is the largest flight time a network will
experience under all variations of conditions. Maximum flight time is
measured at the appropriate V
REF
Guardband boundary.
•
The Minimum Flight Time is the smallest flight time a network will
experience under all variations of conditions. Minimum flight time is
measured at the appropriate V
REF
Guardband boundary.
For more information on flight time and the V
REF
Guardband, see the
Pentium
®
II Processor Developer’s Manual.
GTL+ GTL+ is the bus technology used by the Pentium® Pro processor. This is an
incident wave switching, open-drain bus with pull-up resistors that provide both
the high logic level and termination. It is an enhancement to the GTL (Gunning
Transceiver Logic) technology. See thePentium® II Processor Developer’s
Manual for more details of GTL+.
Term Definition