mpc8640 Freescale Semiconductor, Inc, mpc8640 Datasheet - Page 66

• Manufacturer Part Number: mpc8640
• Description: Integrated Host Processor
• Manufacturer: Freescale Semiconductor, Inc

High-Speed Serial Interfaces (HSSI)
occurs in the 1–15 MHz range. The source impedance of the clock driver should be 50 Ω to match the
transmission line and reduce reflections which are a source of noise to the system.
Table 47
66
At recommended operating conditions with XV
Rising Edge Rate
Falling Edge Rate
Differential Input High Voltage
Differential Input Low Voltage
Rising edge rate (SD n _REF_CLK) to falling edge rate
(SD n _REF_CLK) matching
Notes:
1. Measurement taken from single-ended waveform.
2. Measurement taken from differential waveform.
3. Measured from –200 mV to +200 mV on the differential waveform (derived from SD n _REF_CLK minus SD n _REF_CLK). The
signal must be monotonic through the measurement region for rise and fall time. The 400 mV measurement window is centered
on the differential zero crossing. See
4. Matching applies to the rising edge rate for SD n _REF_CLK and falling edge rate for SD n _REF_CLK. It is measured using a
200 mV window centered on the median cross point where SDn_REF_CLK rising meets SD n _REF_CLK falling. The median
cross point is used to calculate the voltage thresholds the oscilloscope is to use for the edge rate calculations. The rising edge
rate of SD n _REF_CLK should be compared to the falling edge rate of SD n _REF_CLK, and the maximum allowed difference
should not exceed 20% of the slowest edge rate. See
SD n _REF_CLK
SD n _REF_CLK
V
V
IH
IL
= +200 mV
= –200 mV
describes some AC parameters common to PCI Express and Serial RapidIO protocols.
0.0 V
minus
MPC8640 and MPC8640D Integrated Host Processor Hardware Specifications, Rev. 3
Figure 47. Differential Measurement Points for Rise and Fall Time
Parameter
Table 47. SerDes Reference Clock Common AC Parameters
Figure
DD_
SRDS1 or XV
47.
Figure
DD_
SRDS2 = 1.1 V ± 5% and 1.05 V ± 5%.
48.
Rise Edge Rate
Fall Edge Rate
Matching
Rise-Fall
Symbol
V
V
IH
IL
+200
Min
1.0
1.0
—
—
–200
Max
4.0
4.0
—
20
Freescale Semiconductor
V/ns
V/ns
Unit
mV
mV
%
Notes
2, 3
2, 3
1, 4
2
2