Datasheet

DS32EL0124, DS32ELX0124
www.ti.com SNLS284K –MAY 2008–REVISED APRIL 2013
REMOTE SENSE
The remote sense feature can be used when a DS32EL0421 or DS32ELX0421 serializer is directly connected to
a DS32EL0124 or DS32ELX0124 deserializer. Active components in the signal path between the serializer and
the deserializer may interfere with the back channel signaling of the devices.
When remote sense is enabled, the deserializer will cycle through five states to successfully establish a link and
align the data. The state diagram for the deserialiezr is shown in Figure 9. The deserialzer will remain in the low
power IDLE state until it receives an input signal. Once the CDR of the deserializer has locked to the input clock,
the device will enter the LINK DETECT state. While in this state, the deserializer will monitor the line to see if the
serializer is sending the training pattern. While in this state, the deserializer will periodically send a link detect
signal upstream to notify the serializer that it can now send the training pattern. When the deserializer detects
that data coming in on the serial line, it will proceed to the CLOCK ACQUISITION state. While in this state the
deserializer will monitor the incoming data for set periods of time in an attempt to extract the clock from the data.
Once, the deserializer has successfully extracted the clock the device will proceed to the LINK ACQUISITION
STATE. In this state the deserializer will perform lane alignment based on the expected training pattern and then
enter the NORMAL state. If the deserializer is unable to successfully lock or maintain lock, it will break the link
sending the serializer back to the IDLE or LINK DETECT states.
DC-BALANCE DECODER
The DS32EL0124 and DS32ELX0124 have a built-in DC-balance decoder to support AC-coupled applications.
When enabled, the output signal RxOUT4+/-, is treated as a data valid bit. If RxOUT4+/- is low, then the data
output from RxOUT0 - RxOUT3 has been successfully decoded using the 8b/10b coding scheme. If RxOUT4+/-
is high and the outputs RxOUT0 - RxOUT3 are high then an invalid 8b/10b code was received, signifying a bit
error. If RxOUT4+/- is high and the outputs RxOUT0 - RxOUT3 are low then an idle character has been
received. The default idle character is a K28.5 code. In order to properly receive other K codes, they must first be
programmed into the deserializer via the SMBus. The SMBus registers allow for only a single programmable
character.
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