DS125DF1610 Datasheet, PDF (22/81 Pages) Texas Instruments – 9.8 to 12.5 Gbps 16-Channel Retimer

DS125DF1610
SNLS482A – APRIL 2014 – REVISED DECEMBER 2015
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4095
0 64 128
0
0
Phase Position
Figure 4. EOM Full Eye Capture Readout
4032
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To manually control the EOM vertical range, remove scaling control from the state machine then select the
desired range:
1. Channel Reg 0x2C[6] → 0
2. See Table 8
Table 8. Eye Opening Monitor Vertical Range Settings
CH REG 0x11[7:6] VALUE
2’b00
2'b01
2'b10
2'b11
EOM VERTICAL RANGE [mV]
±100
±200
±300
±400
The EOM operates as an under-sampled circuit. This allows the EOM to be useful in identifying over
equalization, ringing and other gross signal conditioning issues. However, the EOM cannot be correlated to a bit
error rate.
The EOM can be accessed in two ways to read out the entire eye plot:
• Multi-byte reads can be used such that data is repeatedly latched out from channel register 0x25.
• Or single byte reads. With single byte reads, the MSB are located in register 0x25 and the LSB are located in
register 0x26. In this mode, the device must be addressed each time a new byte is read.
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