This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

DP83848T: TXD pin be driven during power-on reset

Part Number: DP83848T
Other Parts Discussed in Thread: TIDM-DELFINO-ETHERCAT, DP83849I

X1 is tied to external clock source. The X1 can be floating because the clock source does not drive and is tri-stated during power-on reset.

Is it allowed that X1 is floating during power-on reset?

Our customer is using two DP83848T with ET1100 for EtherCAT Slave Controller. ET1100 clock output (CLK25OUT1) is used as external clock source for X1 on two DP83848T. CLK25OUT1 is not driven during power-on reset.

In BECKHOFF document, it describes that pull-up/pull-down is added to X1.

Application Note PHY Selection Guide
https://download.beckhoff.com/download/document/io/ethercat-development-products/an_phy_selection_guidev2.5.pdf
"X1 must not be floating, add pull-up/pull-down if necessary (e.g., ET1100/ET1200: CLK25Out is not driven before strapping)."

Should pull-up/pull-down be added to X1?

Best regards,

Daisuke