IDT 89HPES48T12G2, User Manual

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IDT SerDes
PES48T12G2 User Manual 7 - 11 April 5, 2013
Notes
Figure 7.3 De-emphasis Applied on Link as a Function of the Fine de-emphasis and Transmit Drive Level
Controls, when the PHY Operates in Gen1 Data Rate with -6.0 dB Nominal de-emphasis
Finally, note that it is possible to turn off de-emphasis (i.e., 0 dB de-emphasis) for a given PHY operating
mode by setting the corresponding transmitter equalization control to 0x0, the coarse de-emphasis control
to a value of 0x3, and the fine de-emphasis control to a value of 0x7.
Programmable Slew Adjustment
The transmitter’s slew rate is controlled by fields in the S[x]TXLCTL0 register. It is possible to select
different settings for Gen1 operation and Gen2 operation. The S[x]TXLCTL0 register contains the following
slew rate controls:
At Gen1 data rate:
TX_SLEW_G1: transmit driver coarse slew control
TX_FSLEW_G1: transmit driver fine slew control
At Gen2 data rate:
TX_SLEW_G2: transmit driver coarse slew control
TX_FSLEW_G2: transmit driver fine slew control
Table 7.5 shows the slew rate settings. The values shown apply to both Gen1 and Gen2 data rates.
TX_SLEW TX_FSLEW
Rise/Fall Times
(20% to 80%)
in Picoseconds
3 5 326
4 266
2 141
0 89
Table 7.5 Transmitter Slew Rate Settings (Part 1 of 2)