mpc8308 Freescale Semiconductor, Inc, mpc8308 Datasheet - Page 35

• Manufacturer Part Number: mpc8308
• Description: Mpc8308 Powerquicc Ii Pro Processor Hardware Specification
• Manufacturer: Freescale Semiconductor, Inc

11.3
The ports on the two ends of a link must transmit data at a rate that is within 600 parts per million (ppm)
of each other at all times. This is specified to allow bit rate clock sources with a ±300 ppm tolerance.
11.4
Following is a summary of the specifications for the physical layer of PCI Express on this device. For
further details as well as the specifications of the transport and data link layer, use the PCI Express Base
Specification, Rev. 1.0a.
11.4.1
Table 34
specified at the component pins.
Freescale Semiconductor
Unit interval
Differential peak-to-peak
output voltage
De-emphasized
differential output voltage
(ratio)
Minimum TX eye width
Maximum time between
the jitter median and
maximum deviation from
the median
Parameter
defines the specifications for the differential output at all transmitters (TXs). The parameters are
Clocking Dependencies
Physical Layer Specifications
Differential Transmitter (TX) Output
MPC8308 PowerQUICC II Pro Processor Hardware Specification, Rev. 1
Table 34. Differential Transmitter (TX) Output Specifications
T
TX-EYE-MEDIAN-t
V
V
MAX-JITTER
TX-DE-RATIO
Symbol
TX-DIFFp-p
T
TX-EYE
UI
o-
Each U
300 ppm. U
account for Spread
Spectrum Clock dictated
variations.
V
V
Ratio of the V
the second and following
bits after a transition
divided by the V
of the first bit after a
transition.
The maximum Transmitter
jitter can be derived as
T
U
Jitter is defined as the
measurement variation of
the crossing points
(V
relation to a recovered TX
UI. A recovered TX UI is
calculated over 3500
consecutive unit intervals
of sample data. Jitter is
measured using all edges
of the 250 consecutive UI
in the center of the 3500
UI used for calculating the
TX UI.
TX-MAX-JITTER
PEDPPTX
TX-D-
PEEWTX
PEDPPTX
|
Comments
PETX
= 0.3 UI.
= 2*|V
= 0 V) in
PETX
is 400 ps ±
PEDPPTX
= 1 -
PEDPPTX
TX-D+
does not
-
of
399.88
–3.0
0.70
Min
0.8
—
Typical
–3.5
400
—
—
—
400.12
Max
–4.0
0.15
1.2
—
Units
dB
ps
UI
UI
V
PCI Express
Notes
2, 3
2, 3
1
2
2
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