The RX termination use modes are covered in this table. This will be added/updated to the 7 Series FPGAs GTP Transceivers User Guide (UG482) in a future release.
| Use Mode |
External AC Coupling |
Term Voltage |
Max Swing mVDPP |
Suggested Protocols and usage notes |
| 1 |
On |
Gnd |
1200 |
Protocol:
GND Terminated interfaces
Attribute Settings:
RX_CM_SEL[1:0] = 2'b01
RXLPM_INCM_CFG = 1'b0
RXLPM_IPCM_CFG = 1'b1
|
| 2 |
On |
AVTT |
1200 |
Protocol:
CEI-6 (1200 mVDPP)
Wireless
Serial RapidIO
Attribute Settings:
RX_CM_SEL[1:0] = 2b00
RXLPM_INCM_CFG = 1'b1
RXLPM_IPCM_CFG = 1'b0
|
| 3 |
On |
800 mV |
2000 |
Protocols:
Optical IF (SONET/SDH/OTU),
XAUI (1600 mVdpp),GbE,
PCIe
CEI-6 (1200 mVDPP)
Wireless
Serial RapidIO
Attribute Settings:
RX_CM_SEL [1:0] = 2b11
RX_CM_TRIM[3:0] = 4b1010
RXLPM_INCM_CFG = 1'b1
RXLPM_IPCM_CFG = 1'b0
|
| 4 |
Off |
Float |
2000 |
Protocol: GPON
Attribute Settings:
RX_CM_SEL[1:0] = 2b10
Depends on circuit implementation. Likely High Common Mode
RXLPM_INCM_CFG = 1'b1
RXLPM_IPCM_CFG = 1'b0
|
Note: The7 SeriesFPGAs GTP Transceivers User Guide (UG482) v1.1.1 RX Analog Front End chapter (table 4-3use mode 1) lists PCI Express as one of the suggested protocols. But the correct RX termination use mode for PCIe is use mode3 as per the table above. This will be fixed in a future version of the user guide when the use mode tables are added/updated.