Alignment, Termination, and Equalization - 3.6 English

7 Series FPGAs Transceivers Wizard (PG168)

Document ID
PG168
Release Date
2022-05-19
Version
3.6 English

Page 4 of the Wizard (This Figure) allows you to set comma characters and control receive equalization and terminal voltage.

Figure 4-13:      Comma Alignment and Equalization—Page 4

X-Ref Target - Figure 4-13

pg168_viv_comma_align_equalization.png

Table: Comma Detection shows the receive comma alignment settings.

Table 4-21:      Comma Detection

Option

Description

Use Comma Detection

Enables receive comma detection. Used to identify comma characters and SONET framing characters in the data stream.

Decode Valid Comma Only

When receive comma detection is enabled, limits the detection to specific defined comma characters.

Comma Value

Select one of the standard comma patterns or User Defined to enter a custom pattern. The XAUI example uses K28.5.

Plus Comma

10-bit binary pattern representing the positive-disparity comma character to match. The right-most bit of the pattern is the first bit to arrive serially.

The XAUI example uses 0101111100 (K28.5).

Minus Comma

10-bit binary pattern representing the negative-disparity comma character to match. The right-most bit of the pattern is the first bit to arrive serially.

The XAUI example uses 1010000011 (K28.5).

Comma Mask

10-bit binary pattern representing the mask for the comma match patterns. A 1 bit indicates the corresponding bit in the comma patterns is to be matched. A 0 bit indicates don’t care for the corresponding bit in the comma patterns.

The XAUI example matches the lower seven bits (K28.5).

Align to...

Any Byte Boundary

When a comma is detected, the data stream is aligned using the comma pattern to the nearest byte boundary.

Two Byte Boundary

When a comma is detected, the data stream is aligned using the comma pattern to the 2-byte boundary.

Four Byte Boundary

When a comma is detected, the data stream is aligned using the comma pattern to the 4-byte boundary

Optional Ports

ENPCOMMAALIGN

Active-High signal that enables the byte boundary alignment process when the plus comma pattern is detected.

ENMCOMMAALIGN

Active-High signal that enables the byte boundary alignment process when the minus comma pattern is detected.

RXSLIDE

Active-High signal that causes the byte alignment to be adjusted by one bit with each assertion. Takes precedence over normal comma alignment.

RXBYTEISALIGNED

Active-High signal indicating that the parallel data stream is aligned to byte boundaries.

RXBYTEREALIGN

Active-High signal indicating that byte alignment has changed with a recent comma detection. Note that data errors can occur with this condition.

RXCOMMADET

Active-High signal indicating the comma alignment logic has detected a comma pattern in the data stream.

Notes:

1.Options not used by the XAUI example are shaded.

Table: Pre-emphasis and Differential Swing details the pre-emphasis and differential swing settings.

Table 4-22:      Pre-emphasis and Differential Swing

Option

Description

Differential Swing and Emphasis Mode

Specifies the transmitter pre-cursor pre-emphasis mode setting. Selecting Custom mode enables user driven settings for differential swing and pre-emphasis level.

The XAUI example uses the Custom mode to dynamically set the pre-emphasis level. See the 7 Series FPGAs GTX/GTH Transceivers User Guide (UG476) [Ref 7] for details.

Table: RX Equalization describes the RX equalization settings.

Table 4-23:      RX Equalization

Option

Description

Equalization Mode

Sets the equalization mode in the receiver. See the 7 Series FPGAs GTX/GTH Transceivers User Guide (UG476) [Ref 7] for details on the decision feedback equalizer.

The XAUI example uses DFE-Auto mode.

Automatic Gain Control

Sets the automatic gain control of the receiver. The value can be set to Auto or Manual.

Use RX Equalizer CTLE3 Adaptation Logic
(DFE mode only)

Applicable only to GTX transceivers. If checked, the CTLE3 adaptation logic is instantiated in the example design. For more information, see Example Design.

Notes:

1.Options not used by the XAUI example are shaded.

Table: RX Termination describes the RX termination settings.

Table 4-24:      RX Termination

Option

Description

Termination Voltage

Selecting GND grounds the internal termination network. Selecting Floating isolates the network. Selecting AVTT applies an internal voltage reference source to the termination network.

Select the Programmable option for Termination Voltage to select RX termination voltage from a drop-down menu.

The XAUI example uses the GND setting.

Table: Optional Ports lists the optional ports available on this page.

Table 4-25:      Optional Ports

Option

Description

TXPOLARITY

Active-High signal to invert the polarity of the transmitter output.

TXINHIBIT

Active-High signal forces transmitter output to steady state.

RXPOLARITY

Active-High signal inverts the polarity of the receive data signal.

TXQPIBIASEN

Active-High signal to enable QPI bias.

TXQPIWEAKUP

Active-High signal transmit for QPI.

RXDFEAGCOVRDEN

Active-High signal for DFE AGC over-ride.

TXPOSTCURSOR

TXPOSTCURSOR port.

TXPRECURSOR

TXPRECURSOR port.

TXQPISENN

Transmit QPI port (negative polarity).

RXDFEMONITOROUT

Receive DFE monitor port.

RXLPMHFOVRDEN

Receive low pass override enable port.

TXQPISENP

Transmit QPI port (positive polarity).

RXDFEMONITORSEL

Receive DFE monitor select port.

RXLPMLFKLOVRDEN

Receive low pass override enable port.

TXQPISTRONGPDOWN

Transmit QPI power down port.

RXDFELPMRESET

Resets the receive DFE/LPM block.

TXDIFFCTRL

Transmit driver swing control.

RXQPISENN

Sense output that registers a 1 or 0 on the MGTRXN pin.

RXQPISENP

Sense output that registers a 1 or 0 on the MGTRXP pin.

RXQPIEN

Disables the RX termination for the QPI protocol.

Notes:

1.Options not used by the XAUI example are shaded.