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I am working with the SoC FPGA Smartfusion2 M2S010-MKR-KIT. It is intended to exchange some data between the SoC and the PC. For that reason, I aim to use Ethernet.

As far as I understood, in order to establish a proper communication using Ethernet, an interface TBI or GMII or MII should be programmed in the fabric in as means to communicate between the MAC and the Ethernet PHY.

Based on what should we decide which interface to use: TBI, GMII or MII?

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  • \$\begingroup\$ Do you have either lying around? If not, how long do you have for the project? \$\endgroup\$ – DonFusili May 22 at 10:25
  • \$\begingroup\$ It is really up to you. Check which one fits your requirements. \$\endgroup\$ – Lior Bilia May 22 at 10:49
  • \$\begingroup\$ @DonFusili do you mean that it is very time consuming? I have 1 week, the thing is, the IP cores of the interfaces are provided in the Libero (the software provided by Microsemi for the FPGA configuration) but still I need to assign the right pins and then write the frimware code or use an OS. Is there an easier way to handle the situation? \$\endgroup\$ – Lavender May 22 at 11:14
  • \$\begingroup\$ It really depends on the bandwidth needed, but I’d suppose emi concerns could be a factor with mii the easiest. \$\endgroup\$ – Erik Friesen May 22 at 11:45
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Well, what Ethernet PHY are you using? Pick an Ethernet PHY, then implement the interface that the PHY wants. Most likely this will be MII or GMII, depending on the speed.

Edit: according to the schematic for your board (https://www.digikey.com/eewiki/download/attachments/64422068/DIGIKEY%20MAKER%20KIT%20REVA1_0_20170606.pdf?version=1&modificationDate=1514924814090&api=v2), the PHY chip is set up in GMII mode.

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  • \$\begingroup\$ I am using the PHY: VSC8541XMV which is embedded in the MakerBoard that I am using. thanks for the insight, I didn't know that the PHY is compatible only with specific interfaces. "The VSC8541-01 device supports RMII version 1.2, RGMII versions 1.3 and 2.0, and GMII/MII MAC interfaces at 1.5 V, 1.8 V, 2.5 V, and 3.3 V operating voltages." from its Datasheet \$\endgroup\$ – Lavender May 24 at 13:25
  • \$\begingroup\$ So, now you need to look at the datasheet and the schematic to figure out what interface the PHY is configured to use. \$\endgroup\$ – alex.forencich May 24 at 15:21

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