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AR# 50146

7 Series FPGA GTH Transceivers - RX Termination Use Modes

Description

This answer record describes the 7 series GTH Transceiver RX termination use modes for different protocols and usage scenarios.

Solution

The RX termination use modes are covered in this table. This is included in v1.8 of the 7 Series FPGAs GTX/GTH Transceivers User Guide (UG476) "RX Analog Front End" section.

Use Mode External AC Coupling Term Voltage Max Swing mVDPP Suggested Protocols and usage notes
1 On Gnd 1200 Port Settings:
RXDFEAGCTRL[4:3] = 2'b01
Attribute Settings:
RX_CM_SEL[1:0] = 2'b01
2 On AVTT 1200 Protocol:
Backplane in LPM Mode,
CEI-6 (1200 mVDPP) in LPM Mode,
Wireless in LPM Mode ,
Serial RapidIO in LPM Mode,
Port Settings:
RXDFEAGCTRL[4:3] = 2'b10
Attribute Settings:
RX_CM_SEL[1:0] = 2b00
3 On 800mV 2000 Protocols:
Optical IF (SONET/SDH/OTU),
SFP+, HD/SD-SDI,
XAUI (1600 mVDPP),GbE,
PCI Express in DFE Mode and LPM mode
Backplane in DFE Mode,
CEI-6 (1200 mVDPP) in DFE Mode,
Wireless in DFE Mode,
Serial RapidIO in DFE Mode,
Interlaken in DFE and LPM Modes
Port Settings:
RXDFEAGCTRL[4:3] = 2'b10
Attribute Settings:
RX_CM_SEL [1:0] = 2b11
RX_CM_TRIM[3:0] = 4b1010
4 Off Float 2000 Protocol: GPON
Port Settings:
Depends on circuit implementation. Likely High Common Mode (Likely, RXDFEAGCTRL[4:3] = 2'b10)
Attribute Settings:
RX_CM_SEL[1:0] = 2b10

Note: This only works in LPM mode.
AR# 50146
Date Created 05/24/2012
Last Updated 07/05/2013
Status Active
Type General Article
Devices
  • Virtex-7
  • Virtex-7 HT