transmitter and TX buffer are enabled, the TX buffer drives normal differential data,
and the differential impedance on both TX and RX lines is in the range of 80 (min),
100 (typ), 120 (max) Ω. For more details on the termination modes, refer to the
description for PMA attribute code 0x002B in the PMA Attribute Codes section.
Note: Differential impedance values are not programmable (after power-up, the differential
impedance typically ranges from 80 Ω to 120 Ω).
Related Information
• PMA Register Map on page 165
• PMA Attribute Codes on page 170
3.1.1.1.2. TX Equalizer
The TX equalizer has one Post-tap, three Pre-taps and one Main Tap (attenuation). The
frequency response of the filter is chosen to compensate for the channel impairments
such as intersymbol interference (ISI), crosstalk, frequency-dependent losses and
reflections. When a signal is transmitted over a channel, the high-frequency
components get attenuated. To save power, de-emphasis is used instead of pre-
emphasis. This results in a bit stream which is pre-distorted by the equalizer over
several bits.
Table 25. PMA Transmitter Programmable Parameters
Parameter Mode
Attenuation (ATTN) PAM4, NRZ
Post-tap1 (POST) PAM4, NRZ
Pre-tap1 (PRE1) PAM4, NRZ
Pre-tap2 (PRE2) PAM4, NRZ
Pre-tap3 (PRE3) PAM4, NRZ
Refer to the resources linked below to help calculate transmitter equalization.
Details on TX equalization settings for PAM4 and NRZ signals
TX equalization parameters take the following range.
Table 26. TX Equalization Settings for PAM4 and NRZ Signals
Cursor Rule
ATTN 0 ≤ ATTN ≤ 26
POST -18 ≤ POST ≤ 18
PRE1
-10 ≤ PRE1 ≤ 10
Increment/decrement by 2
PRE2
-15 ≤ PRE2 ≤ 15
Increment/decrement by 2
PRE3 -1 ≤ PRE3 ≤ 1
For more details on TX equalization programmability, refer to the description for code
0x0015 in the PMA Attribute Codes section.
3. Intel Stratix 10 E-Tile Transceiver PHY Architecture
UG-20056 | 2019.02.04
Intel
®
Stratix
®
10 E-Tile Transceiver PHY User Guide
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