DP83867IR: Sometimes ,the DP83867 can not able to ping Gigabit ethernet but can ping 100M lan。

Hi Johnny,

What condition is your register set from? I would like to see the registers in 1000M mode when ping is not possible. From the registers you are showing, there is no link according to register 0x1 bit2.

Your clock source into the DP3867 looks like it is a 3.3Vpk-pk swing, which is outside of the specs of the DP83867. The DP83867 needs a 1.8Vpk-pk swing input. A cap voltage divider should be placed on this XI pin for reliability of the 867.

Is there a jitter spec on the 25MHz clock you are using for reference? Can it be posted here?

Best Regards,

Hi Rob，
The register I'v Posted is in 1000M mode when ping is not possible.

I try to use a cap voltage divider for the clock source，but the ether is still can not ping with 1000M .

The 25MHz clock‘s jitter is 0.6ps as tested，is't reach the need？

I checked the chip datasheet，The VDD1P1 is recommended as 1.045~1.155V when in TQFP footprint，we use a 1.0V here in the SCH.Can it be affect？
Why the 0x4 register can not take effect when I configured it？

Hi Johnny,

The VDD1P1 must be in the range in the datasheet. We have noted that low voltage to this supply in particular can cause link stability issues.

I would also recommend, for the purpose of debug, to remove the beads on the supplies for 1.1V and 2.5V. L28 and L30. Please replace these with 0 ohm resistors.

Finally, do you have a strap on RX_CTRL pin? RX_CTRL must be strapped into mode 3 or link establishment issues may be seen with certain link partners.

Best Regards,