Receiver Equalization Controls; Table 8.8 Serdes Transmit Drive Swing In Low Swing Mode At Gen2 Speed - Renesas IDT 89HPES48H12G2 User Manual

Pci express switch
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IDT SerDes
Notes
PES48H12G2 User Manual

Table 8.8 SerDes Transmit Drive Swing in Low Swing Mode at Gen2 Speed

When the PHY enters the Polling.Compliance state and low-swing mode is enabled, the following
occurs:
– The transmit drive level is selected by the Transmit Margin (TM) field in the PCIELCTL2 register.
This field has specific transmit margin levels for full-swing and low-swing mode. The values corre-
sponding to low-swing mode are applied.
– De-emphasis is turned off.

Receiver Equalization Controls

The switch contains SerDes receiver equalization controls on a per-lane basis. The receiver equaliza-
tion circuit has two controls which may be programmed via the SerDes Receiver Equalization Lane Control
(S[x]RXEQLCTL) register. These are:
– Receiver Equalization Zero (RXEQZ): Increases the high-frequency gain of the equalizer.
– Receiver Equalization Boost (RXEQB): Reduces the low-frequency gain of the equalizer.
Together, RXEQZ and RXEQB provide wide programmability and fine grain control over the equalizer's
boost. Refer to the definition of the S[x]RXEQLCTL register for further details on programming these
controls.
Drive Level
TDVL_LSG2
764
0x0F
737
0x0E
709
0x0D
682
0x0C
649
0x0B
616
0x0A
583
0x09
550
0x08
506
0x07
462
0x06
418
0x05
374
0x04
320
0x03
266
0x02
212
0x01
158
0x00
8 - 14
April 5, 2013

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