DP83822H: RX_D3 strap in RMII mode

Cera Wei

Intellectual 2010 points

Part Number: DP83822H

Hi Team,

In RMII master mode, RX_D3 is used as 50MHz clock output by default. While, RX_D3 can also be used as strap pin, and in datasheet, we see the example of pull-up or pull-down (Mode1/4) design recommendation. How can we strap to Mode_2/3?

Thanks,

Cera

over 4 years ago

0 Kallikuppa Sreenivasa over 4 years ago

TI__Guru**** 189709 points

Hello Cera,

Thank you for your query.

Please refer to 8.5 Programming 8.5.1 Hardware Bootstrap Configurations of the datasheet.

The below documents also could help.

https://www.ti.com/lit/an/snla262/snla262.pdf

Regards,

Sreenivasa

0 Cera Wei over 4 years ago

TI__Intellectual 2010 points

Hi Sreenivasa,

Thanks for your timely help.

From datasheet 8.5.2, if this pin is used as both Strap and LED in one design, only two mode can be used (pull-up and pull-down). How can we configure Mode2/3 when this pin is also used as 50MHz clock output? thanks!

Regards,

Cera

0 Cera Wei over 4 years ago

TI__Intellectual 2010 points

Hi Sreenivasa,

Thanks for your timely help.

Regards,

Cera

0 Kallikuppa Sreenivasa over 4 years ago in reply to Cera Wei

TI__Guru**** 189709 points

Hello Cera,

Thank you for the query.

The RX_D3 has an internal PD.

Table 9 in the data sheet provides Recommended 4-Level Strap Resistor Ratios. Please use the PD ratios.

Regards,

Sreenivasa

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DP83822H: RX_D3 strap in RMII mode