Enabling And Disabling Loopback Modes Using Direct Reconfiguration Flow - Intel Arria 10 User Manual

6. Reconfiguration Interface and Dynamic Reconfiguration
UG-01143 | 2018.06.15
6.12.4. Enabling and Disabling Loopback Modes Using Direct
Reconfiguration Flow
Arria 10 devices have three loopback modes:
• Serial Loopback
• Reverse Serial Loopback (Pre-CDR)
• Reverse Serial Loopback (Post-CDR)
The loopback mode can be dynamically reconfigured by accessing the register space.
Serial Loopback Mode
In serial loopback mode, a path exists between the serializer of the transmitter and
the CDR of the receiver, so that the data from the CDR is recovered from the serializer
while the data from the receiver serial input pin is ignored. You can enable or disable
this mode.
Figure 273. Serial Loopback Mode
To enable serial loopback mode:
1. Perform the necessary steps from steps 1 to 7 in Steps to Perform Dynamic
Reconfiguration.
2. Perform a read-modify-write to address 0x2E1 to set bit 0 to 1'b1
3. Perform the necessary steps from steps 9 to 12 in Steps to Perform Dynamic
Reconfiguration.
To disable serial loopback mode:
1. Perform the necessary steps from steps 1 to 7 in Steps to Perform Dynamic
Reconfiguration.
2. Perform a read-modify-write to address 0x2E1 to set bit 0 to 1'b0
3. Perform the necessary steps from steps 9 to 12 in Steps to Perform Dynamic
Reconfiguration.
You can also enable the serial loopback mode by turning on Enable rx_seriallpbken
port in the Native PHY IP Parameter Editor and driving the port to 1'b1.
Transmitter
PCS PMA
Serializer
Receiver
PCS PMA
Deserializer
Serial Loopback
CDR
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Intel Arria 10 Transceiver PHY User Guide
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