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Zarquin's avatar
Zarquin
Icon for Occasional Contributor rankOccasional Contributor
3 years ago
Solved

Can a 1000mbps RGMII TSE communicate with a 100mbps PC?

Dear community, is it possible to establish an Ethernet connection from Cyclone V Dev Kit to my 100Mbps LAN PC? And if so, what configuration is necessary? On the FPGA, a Triple Speed Ethernet IP M...
Ethernet
  • FvM's avatar
    FvM
    3 years ago
    Hi,
    RGMII reference clocks and data rate changes with ethernet speed and has to switched in MAC. Reading negotiated speed through MI is the usual way to handle it.
Zarquin's avatar
Zarquin
Icon for Occasional Contributor rankOccasional Contributor
3 years ago

Hi FvM,

thank you very much for the answer.

Do I have to adjust the tx_clock to the autonegotiated speed in the PHY?

More precisely: Do I have to query the speed from the corresponding Marvell PHY register and adjust the tx_clock frequency generated by the FPGA to the actual speed? Or can the tx_clock continue to operate at 125MHz ?

FvM's avatar
FvM
Icon for Super Contributor rankSuper Contributor
3 years ago
Hi,
yes, RGMII reference clocks and data rate change according to 10/100/1000 ethernet speed.