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TMS320F28388D: RevMII Connection to remote MAC

Matthias Höcht
Prodigy 10 points
Part Number: TMS320F28388D

I am confused by the TMS320F28388D TRM ( SPRUII0D ) on the RevMII interface.

Table 43-3:

  1. ENET_MII_COL is Type Input but remote MAC requires this to be an output on the TMS320 RevMII
  2. ENET_MII_CRS is Type Input but remote MAC requires this to be an output on the TMS320 RevMII

According to https://www.eetimes.com/reverse-media-independent-interface-revmii-block-architecture/ these two signals should be outputs generated by the RevMII block (which is inside the TMS320F28388D)

Also Table 43-3 does not match Figure 43-3:

  1. ENET_MII_TX_CLK is an input to the TMS320 in Figure 43-3 but an output in Table 43-3
  2. ENET_MII_RX_CLK in an input to the TMS320 in Figure 43-3 but an output in Table 43-3

My assumtion on how to connect the TMS320 RevMII to an external MAC is to connect the TX-signals from the TMS320 RevMII to the RX-signals of the external MII MAC and vice versa.

Are these connections correct?

Also my remote MAC does not offer an TX_ERR signal, so can I connect the RX_ERR on the TMS320 to GND?

And can I also connect RX_ERR on the remote MAC to GND?

  • +1
    TI__Mastermind 41895 points

    In RevMII mode you are correct COL and CRS should be Outputs. Those are typographical errors.

    Frankly I have no idea how you correctly determined that the Tx and Rx signals should be crossed, but you are correct. In my mind this is supposed to look like a PHY to the external MAC so I would have connected Rx to Rx as you do with a PHY.

    I have submitted literature bugs to have this information updated. 

    I would recommend tieing RX_ERR to ground, however this note seems to indicate it is not required.

    Regards,
    Cody