DP83867IR: DP83867 strap device configuration fail

Hi Iwata-san,

Yes, it is possible to change the RGMII Clock skew via registers after the device powers up. Please note that Software settings are removed after power-up and hard reset. This means that software register settings need to be re-programmed after every power-up and hard reset.

-Regards,
Aniruddha

Hi Aniruddha-san,

Thank you for your support.

We would like to double-check.
Even if the strap device configuration was failed into "not applicable" state (N/A), especially for LED_ and GPIO_0, are there any problems once we could configure the appropriate resisters?

We are confusing based on the statement on the NOTEs in the DP83867IR datasheet in as below.

NOTE
Strap modes 1 and 2 are not applicable for RX_DV/RX_CTRL. The RX_DV/RX_CTRL
strap must be configured for strap mode 3 or strap mode 4. If the RX_CTRL pin cannot be
strapped to mode 3 or mode 4, bit[7] of Configuration Register 4 (address 0x0031) must
be cleared to 0.

NOTE
Strap modes 2 and 4 are not applicable for LED_0. The LED_0 strap must be configured
for strap mode 1 or strap mode 3.

Best regards,
Iwata Etsuji

Aniruddha-san,

I would like to additionally confirm the following.

What is the difference between RX_DV/RX_CTRL and LED_0?

In the case of RX_DV/RX_CTRL, the datasheet says "If the RX_CTRL pin cannot be
strapped to mode 3 or mode 4, bit[7] of Configuration Register 4 (address 0x0031) must
be cleared to 0."

However, in the case of LED_0, the datasheet doesn't say the same as RX_DV/RX_CTRL. Only the LED_0 strap must be configured
for strap mode 1 or strap mode 3...

Is it possible to configure Autoneg Disable(= 4-level strap of RX_DV/RX_CTRL pin) with bit[12] of BMCR (address 0x0000) , without bit[7]=0 of Configuration Register 4?

Best regards,
Iwata Etsuji

Hello Iwata-san,

We will not be able to guarantee PHY performance if it is strapped in not applicable mode. I would strongly recommend strapping in applicable modes only.

-Regards,
Aniruddha