Hello,
On our device we use Marvell 88EA1512 PHY connected to TDA4VM via SGMII. 1Gbit mode works well, but in 100Mbit mode we observe 50% packet loss. Also we noticed that packet loss issue occurs (roughly speaking) 4 of 5 times we reestablish the link.
I found several related discussions on E2E:
Marvell support has following comments on this topic:
> The PHY can only support 8B preamble (7B preamble + 1B SFD). The 8B preamble is standard. If the frame has 7B preamble (6B preamble + 1B SFD) the PHY will not recognize the frames.
> They saw another case where an FPGA was sending a PHY alternating 8B preamble and 7B preamble and the PHY was only 50% of the packets.
> There is no setting in the PHY to change this.
> 8B is standard and all Marvell PHYs have this requirement.
> They saw another case where an FPGA was sending a PHY alternating 8B preamble and 7B preamble and the PHY was only 50% of the packets.
> There is no setting in the PHY to change this.
> 8B is standard and all Marvell PHYs have this requirement.
Is it possible to configure TDA4VM SGMII port to generate standard compatible preamble in 100Mbit mode?
Best regards,
Ivan Frederiks
