We are using Arria V GX FPGA, and the IP Core TSE 1000Base-X/SGMII with PCS and PMA. I am trying to activate the PHY loopback but couldn’t get it to work as it’s my first time to work with Ethernet. The sequence is as follows:
Write to PCS Control register 0x00 : “0100000101100000”
So I enable the Uniderectional option to be able to send data without a link partner Activate gigabit mode Activate loopback mode
If_Mode register 0x14 : "0000000000001001"
SGMII_ENA set to 1, USE_SGMII_AN set to 0, SGMII_SPEED to gigabit mode
Then I reset the PCS by setting bit 15 of control register to 1
Can I afterwards start to write data by setting the gmii_tx_clk_en to 1 and writing a byte to gmii_tx_d without having a valid link? Or I still need to do something because currently I don’t see any data on rx. I also read the PCS registers and confirmed that they were correctly written. Thanks in advance.