1000Base-KX Mode

valkir — Mon, 15 Nov 2021 12:57:32 GMT

Hello

On our T2080 board we are trying to configure two backplane Ethernet interfaces in 1000Base-KX mode. We are following the procedure of the Para 19.6.1.2 1000Base-KX from the T2080RM. This seems to be working. However we are getting troubles when we are trying to access 1000Base-KX MDIO devices.

As according to the documentation there are several Clause 45 PHY devices available: 0x03, 0x07 and 0x1d.

However we are not able to access those devices.

The documentation for T2080 (Para 19.5.5 of the RM) states:

The 1000Base-KX PCS register space is selected when the associated
SGMIInCR1[MDEV_PORT] matches the Ethernet MAC port address
(MDIO_CTL[PORT_ADDR]) and the device address (MDIO_CTL[DEV_ADDR]) is
03h.

But if we change default value 0x0 in MDEV_PORT field of the corresponding register SGMIInCR1 to 0x03 we are not getting the expected values by accessing the device with the address 0x3.

What is the right way to access the 1000Base-KX MDIO registers, defined by in Para 19.5.5 - 19.5.7 ?

Configuration used:

SerDes configuration BC-18 from the Table 19-1 with Lanes C and D connected to the backplane in SGMII mode (by RCW) and re configured to 1000Base-KX after reset.

As we understand these lanes are mapped to the SGMII_H and SGMII_G

Re: 1000Base-KX Mode

valkir — Tue, 16 Nov 2021 14:06:29 GMT

Well, we are able to read these registers now using Clause 45 approach.
A reference to DEV_ADDR in the documentation caused the confusion as we thought this is the PHY address.

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