MPC8560CPXAPDB datasheet(67/108 Pages) FREESCALE

67 / 108 page

MPC8560 Integrated Processor Hardware Specifications, Rev. 3.1

Freescale Semiconductor

RapidIO

The eye pattern for a data signal is generated by making a large number of recordings of the signal and then

overlaying the recordings. The number of recordings used to generate the eye shall be large enough that further

increasing the number of recordings used does not cause the resulting eye pattern to change from one that complies

with the RapidIO transmit mask to one that does not. Each data signal in the interface shall be carrying random or

pseudo-random data when the recordings are made. If pseudo-random data is used, the length of the pseudo-random

sequence (repeat length) shall be long enough that increasing the length of the sequence does not cause the resulting

eye pattern to change from one that complies with the RapidIO transmit mask to one that does not comply with the

mask. The data carried by any given data signal in the interface may not be correlated with the data carried by any

other data signal in the interface. The zero-crossings of the clock associated with a data signal shall be used as the

timing reference for aligning the multiple recordings of the data signal when the recordings are overlaid.

While the method used to make the recordings and overlay them to form the eye pattern is not specified, the method

used shall be demonstrably equivalent to the following method. The signal under test is repeatedly recorded with a

digital oscilloscope in infinite persistence mode. Each recording is triggered by a zero-crossing of the clock

associated with the data signal under test. Roughly half of the recordings are triggered by positive-going clock

zero-crossings and roughly half are triggered by negative-going clock zero-crossings. Each recording is at least 1.9

UI in length (to ensure that at least one complete eye is formed) and begins 0.5 UI before the trigger point (0.5 UI

before the associated clock zero-crossing). Depending on the length of the individual recordings used to generate

the eye pattern, one or more complete eyes will be formed. Regardless of the number of eyes, the eye whose center

is immediately to the right of the trigger point is the eye used for compliance testing.

An example of an eye pattern generated using the above method with recordings 3 UI in length is shown in

Figure 45. In this example, there is no skew between the signal under test and the associated clock used to trigger

the recordings. If skew was present, the eye pattern would be shifted to the left or right relative to the oscilloscope

trigger point.

Figure 45. Example Driver Output Eye Pattern

13.3.2 RapidIO Receiver AC Timing Specifications

The RapidIO receiver AC timing specifications are provided in Table 50. A receiver shall comply with the

specifications for each data rate/frequency for which operation of the receiver is specified. Unless otherwise

specified, these specifications are subject to the following conditions.

–

0.5 UI

1.0 UI

Oscilloscope

(Recording)

Trigger Point

Eye Pattern

Eye Used for

Compliance

Testing

MPC8560CPXAPDB 데이터시트(PDF) 67 Page - Freescale Semiconductor, Inc