Intel 915GME - Manual (Page 10)

Mobile Intel ® 915GME Express Chipset —About This Manual
Mobile Intel ® 915GME Express Chipset
Development Kit User’s Manual April 2007
10 Order Number: 317230-001US
needed to ensure the setup time of the receiver. More precisely,
flight time is defined as:
• The time difference between a signal at the input pin of a
receiving agent crossing the switching voltage (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 the switching voltage
when the driver is driving a test load used to specify the
driver’s AC timings.
• Maximum and Minimum Flight Time - Flight time variations
are caused by many different parameters. The more
obvious causes include variation of the board dielectric
constant, changes in load condition, crosstalk, power 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.
• Maximum flight time is the largest acceptable flight time a
network will experience under all conditions.
• Minimum flight time is the smallest acceptable flight time a
network will experience under all conditions.
IrDA IrDA is an acronym for Infrared Data Association, and this
association has outlined a specification for serial communication
between two devices via a bi-directional infrared data port. The
915GM platform has such a port and it is located on the rear of
the platform between the two USB connectors.
ISI Inter-symbol interference is the effect of a previous signal (or
transition) on the interconnect delay. For example, when a
signal is transmitted down a line and the reflections due to the
transition have not completely dissipated, the following data
transition launched onto the bus is affected. ISI is dependent
upon frequency, time delay of the line, and the reflection
coefficient at the driver and receiver. ISI may impact both timing
and signal integrity.
Network The network is the trace of a Printed Circuit Board (PCB) that
completes an electrical connection between two or more
components.
Overshoot The maximum voltage observed for a signal at the device pad,
measured with respect to VCC.
Pad The electrical contact point of a semiconductor die to the
package substrate. A pad is only observable in simulations.
Pin The contact point of a component package to the traces on a
substrate, such as the motherboard. Signal quality and timings
may be measured at the pin.
Power-Good “Power-Good,” “PWRGOOD,” or “CPUPWRGOOD” (an active high
signal) indicates that all of the system power supplies and clocks
are stable. PWRGOOD should go active a predetermined time
after system voltages are stable and should go inactive as soon
as any of these voltages fail their specifications.
Ringback The voltage to which a signal changes after reaching its
maximum absolute value. Ringback may be caused by
reflections, driver oscillations, or other transmission line
phenomena.