4
XCVR channel TX to RX loopback test can be done in 2 ways which is either via internal serial loopback test in
Physical Medium Attachment (PMA) block or via external on board loopback using the FPGA Mezzanine Card
(FMC) loopback card.
Figure 2 indicates the overview diagram of serial loopback path within PMA block.
Figure 2. Overview diagram of serial loopback path
In the XCVR toolkit, user needs to select preferred loopback mode before starting the BER testing.
This design example will exercise following loopback mode test.
•
Loopback mode = off (user to manually perform on board external loopback via FPGA FMC loopback
card)
•
Loopback mode = serial loopback (activate serial loopback path within XCVR PMA block)
How to Setup the Development Kits for XCVR Loopback Test
Follow these steps to setup the hardware to run the reference design:
1. Connect the FMC loopback card to the FMC port on the Cyclone 10 GX Development Kit Board
2. Ensure Switch 9 (S9) settings of the Development Kit B
oard is set to “on” position
3. Connect the Micro USB cable to the USB Blaster connector on the Development Kit Board
4. Connect the power adapter shipped with the Development Kit Board to power supply jack
5. Turn On the power for the Development Kit Board. The hardware system is now ready for testing.
