DP83867CS: Can SGMII polarity be reversed?

Bob C

Part Number: DP83867CS

Hello,

I'm not finding it in the datasheet, but maybe there is a bit somewhere that would let me Switch the P and N on the SGMII RX and TX pairs.

Every pair of a multi-PHY design requires a cross over to match up with the FPGA were using.

I'm going to have problems if I switch the P and N on SGMII without some sort of internal polarity correction, right?

Thank you,

Bob

over 7 years ago

0 Bob C over 7 years ago

Intellectual 615 points

BTW, I ran a test by swapping the SGMII P and N wires (via SMA cables). I found that the PHY won't negotiate SGMII with the MAC when the wires are swapped. So it appears that there isn't any form of self correction in the PHY for polarity reversal on the SGMII.

However, maybe there is a bit in the MDIO registers? Please let me know if I'm just not finding it.

Bob

0 Geet Modi over 7 years ago in reply to Bob C

TI__Mastermind 26320 points

Hi Bob,

Please try following register configuration:

1. Read 0x01D0
2. Write 1 to bit 0 to revert RX pin polarity
2. Write 1 to bit 1 to revert TX pin polarity.

Regards,
Geet

0 Geet Modi over 7 years ago in reply to Geet Modi

TI__Mastermind 26320 points

Sorry

1. Read 0x01D5
2. Write 1 to bit 0 to revert RX pin polarity
2. Write 1 to bit 1 to revert TX pin polarity

Regards,
Geet

0 Geet Modi over 7 years ago in reply to Geet Modi

TI__Mastermind 26320 points

Hi,

I am closing this thread. Incase issue persist, please open new thread with reference to this thread.

Regards,
Geet

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DP83867CS: Can SGMII polarity be reversed?