DP83867IR: RGMII termination resistors

Niels Ole Jorgensen

Part Number: DP83867IR

Hi.

The DP83867IR phy has build in termination resistors for the MAC IO (RGMII) interface. These termination resistors are trimmed and the trimming value can be read out in register IO_MUX_CFG at address 0x0170 bit 4:0.

My question is: How big can the variation of this calibration be? I have read out a variation for only 1 bit for two different phy's.

Best regards

Niels Ole Jørgensen

over 3 years ago

0 Hillman Lin over 3 years ago

TI__Mastermind 26095 points

Hi Niels,

The purpose of this register is to bring the PHY close to 50 ohms. We are not sure about the exact value since we are not categorized by value for the termination.

Regards,

Hillman Lin

0 Niels Ole Jorgensen over 3 years ago in reply to Hillman Lin

Prodigy 130 points

Hi Hillman Lin

Thanks for your quick answer.

So as I read your answer, it is not possible for you to tell how much the register value for the termination can variate.

Best regards

Niels Ole Jørgensen

+1 Hillman Lin over 3 years ago in reply to Niels Ole Jorgensen

TI__Mastermind 26095 points

Hi Niels,

From the register, you can see there are 32 steps of variation. But each steps has a different variation in resistors value. Sorry this information cannot share it externally.

Regards,

Hillman Lin

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DP83867IR: RGMII termination resistors