RapidIO
Table 52. RapidIO Receiver AC Timing Specifications—1 Gbps Data Rate
Range
Characteristic
Symbol
Unit
Notes
Min
Max
Duty cycle of the clock input
DC
DV
47
425
—
53
—
%
ps
ps
1, 5
2
Data valid
Allowable static skew between any two data inputs
within a 8-/9-bit group
tDPAIR
300
3
Allowable static skew of data inputs to associated clock
tSKEW,PAIR
–200
200
ps
4
Notes:
1.Measured at VID = 0 V.
2.Measured using the RapidIO receive mask shown in Figure 39.
3.See Figure 42.
4.See Figure 41 and Figure 42.
5.Guaranteed by design.
The compliance of receiver input signals RD[0:15] and RFRAME with their minimum data valid window
(DV) specification shall be determined by generating an eye pattern for each of the data signals and
comparing the eye pattern of each data signal with the RapidIO receive mask shown in Figure 39. The
value of X2 used to construct the mask shall be (1 – DV )/2. The ±100 mV minimum data valid and
min
±600 mV maximum input voltage values are from the DC specification. A signal is compliant with the data
valid window specification if and only if the receive mask can be positioned on the signal’s eye pattern
such that the eye pattern falls entirely within the unshaded portion of the mask.
600
100
0
–100
DV
–600
0
X2
1–X2
1
Time (UI)
Figure 39. RapidIO Receive Mask
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 receive 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
MPC8540 Integrated Processor Hardware Specifications, Rev. 4
Freescale Semiconductor
63
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