DP83867IR: RGMII Not Enabled at Startup Despite RX_D6 Strap Configuration

Ankita Chaudhary

Part Number: DP83867IR

We are using the DP83867IR PHY.Please find the attached below schematic for strap configuration. According to the datasheet, RX_D6 is the RGMII Disable strap and maps to bit 7 (RGMII Enable) of the RGMIICTL register (0x0032). Our schematic shows RX_D6 strapped high, which should enable RGMII mode at power-up. However, the device does not appear to initialize in RGMII mode. Please help verify the strap configuration and identify any conditions that might cause the PHY to boot in GMII mode despite RX_D6 being strapped high?

Datasheet

1 month ago

0 Shane Hauser 1 month ago

TI__Mastermind 38705 points

Hi Ankita,

The strap network you have on RX_D6 will place the pin in strap mode 3:

Strap mode 3 sets 'RGMII Disable' to 1,

Can you remove the pullup and pulldown resistors on RX_D6 to place it in strap mode 0 and see if it initializes correctly? This should set RGMII Disable to 0.

Best,

Shane

0 Ankita Chaudhary 1 month ago in reply to Shane Hauser

Prodigy 10 points

Okay, I will try that. I have one more clarification: could you please explain this table? It seems to contain contradictory information. Is this a mistake in the datasheet?

0 Shane Hauser 1 month ago in reply to Ankita Chaudhary

TI__Mastermind 38705 points

That table relates the RGMII ENABLE register (0x0032[7]) to the device functional mode. This table does not include the RX_D6 'RGMII Disable' strap. The RX_D6 'RGMII disable' strap should be opposite the RGMII ENABLE register.

Best,

Shane

Interface

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DP83867IR: RGMII Not Enabled at Startup Despite RX_D6 Strap Configuration