mpc8308 Freescale Semiconductor, Inc, mpc8308 Datasheet - Page 33

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

The other detailed AC requirements of the SerDes reference clocks is defined by each interface protocol
based on application usage. For detailed information, see
SerDes Clocks.”
Freescale Semiconductor
At recommended operating conditions with XCOREVDD= 1.0V ± 5%
Rising edge rate (SD_REF_CLK) to falling edge rate
(SD_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_REF_CLK minus SD_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
4. Matching applies to rising edge rate for SD_REF_CLK and falling edge rate for SD_REF_CLK. It is measured using a 200 mV
window centered on the median cross point where SD_REF_CLK rising meets SD_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 Rise Edge Rate of
SD_REF_CLK should be compared to the Fall Edge Rate of SD_REF_CLK, the maximum allowed difference should not exceed
20% of the slowest edge rate (See
SD_REF_CLK
SD_REF_CLK
V
V
IH
IL
= -200 mV
=
minus
0.0 V
+200
SD_REF_CLK
SD_REF_CLK
Figure 25. Single-Ended Measurement Points for Rise and Fall Time Matching
Figure 24. Differential Measurement Points for Rise and Fall Time
MPC8308 PowerQUICC II Pro Processor Hardware Specification, Rev. 1
Table 32. SerDes Reference Clock AC Parameters (continued)
Parameter
(Figure
Figure
24).
25).
SD_REF_CLK
SD_REF_CLK
Section 11.2, “AC Requirements for PCI Express
Matching
Rise-Fall
Symbol
Min
—
High-Speed Serial Interfaces (HSSI)
Max
20
Unit
%
Notes
1, 4
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