IDT PCI Express 89HPES32NT24xG2, User Manual, Page: 157 / 744

IDT SerDes
PES32NT24xG2 User Manual 8 - 9 January 30, 2013
Notes
Table 8.8 shows a number of possible settings for the drive and de-emphasis in Gen 2 mode with -6.0
dB de-emphasis
1
. The default setting is highlighted. As mentioned above, the PCI Express Base Specifica-
tion allows an error of up to +/- 0.5 dB on the de-emphasis. All settings listed in the table ensure that the de-
emphasis is kept within the allowable range.
1.
Table values are based on simulations using the Snowbush SerDes HSPICE model and device package s-
parameters. Values are sampled at the device pins. The simulation assumes typical conditions, with VddPEA =
VddPETA = 1.0V, VddPEHA = 2.5V, and TX_AMPBOOST = 0x0. The values in the tables may differ from those of
post-silicon characterization. Please refer to the device data sheet for post-silicon device characterization data.
Transmit Levels
Settings of Relevant Fields in the
S[x]TXLCTL0 & S[x]TXLCTL1 Registers
Drive
Level
(mV)
De-empha-
sis (dB)
De-empha-
sized Drive
Level (mV)
TDVL_FS6DBG2 CDC_FS6DBG2 FDC_FS6DBG2 TX_SLEW_G2
845
-6.3 407
0x19 0x6 0x3 0x0
842 -6.4 402 0x18 0x6 0x3 0x0
838 -6.3 407 0x17 0x6 0x3 0x0
835 -6.1 411 0x16 0x6 0x3 0x0
831 -6.0 416 0x15 0x6 0x3 0x0
827 -5.9 421 0x14 0x6 0x3 0x0
818 -5.9 416 0x13 0x6 0x3 0x0
808 -5.9 412 0x12 0x6 0x3 0x0
784 -5.9 398 0x11 0x6 0x3 0x0
760 -5.9 385 0x10 0x6 0x3 0x0
736 -5.9 371 0xF 0x5 0x3 0x0
712 -6.0 358 0xE 0x5 0x3 0x0
688 -6.0 344 0xD 0x5 0x3 0x0
652 -5.9 329 0xC 0x5 0x3 0x0
617 -5.8 315 0xB 0x5 0x3 0x0
581 -5.7 300 0xA 0x5 0x2 0x0
545 -5.6 285 0x9 0x5 0x2 0x0
501 -5.7 260 0x8 0x5 0x2 0x0
458 -5.8 235 0x7 0x5 0x2 0x0
414 -5.9 210 0x6 0x5 0x2 0x0
370 -6.0 185 0x5 0x5 0x2 0x0
319 -5.9 161 0x4 0x5 0x2 0x0
268 -5.8 136 0x3 0x5 0x2 0x0
217 -5.7 112 0x2 0x5 0x1 0x0
166 -5.6 88 0x1 0x5 0x1 0x0
115 -5.5 63 0x0 0x5 0x1 0x0
Table 8.8 SerDes Transmit Driver Settings in Gen 2 Mode with -6.0 dB de-emphasis