MOTOROLA
Chapter 5. System Design Considerations
5-5
Repeater Mode
5.5.3
Word Synchronization Mode
Word synchronization may be used in repeater mode. This allows the incoming bytes to be
synchronized into their corresponding words, removing cable skew from the transmission
source and re-establishing synchronization.
Similar to byte alignment, the word synchronization sequence must be repeated twice, once
for the repeater and once for destination’s receiver. A word synchronization event must be
transmitted followed by a second word synchronization event to enable the entire link to
establish word synchronization. Byte alignment must be established, as described in
Section 5.5.2, “Byte Alignment Mode,” prior to word synchronization.
5.5.4
Recovered Clock Mode
The MC92603’s four transmitters are timed exclusively to the reference clock domain;
therefore, the recovered clock mode cannot be used in repeater mode. The setting on the
recovered clock enable input, RCCE, is ignored when in repeater mode, and all data is
timed to the reference clock.
5.5.5
Add/Drop Idle Mode
Repeater mode is timed exclusively to the reference clock domain as stated above. A
frequency offset between the source transmitter and the repeater will cause the repeater’s
receiver to eventually overrun/underrun. To ensure that overrun/underrun does not cause
data to be lost, ADIE must be high. The repeater repeats or drops data from the data stream
to maintain alignment to the reference clock (see Section 3.6.2, “Reference Clock Timing
Mode (RCCE = Low),” for specifics).
5.5.6
Half-Speed Mode
Half-speed mode simply affects the frequency of the reference clock that must be provided
and the timing of the receiver interface. This mode is supported in the repeater mode.
Summary of Contents for MC92603
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