On ref-design mc1381 I have noticed that there are serial resistors on every single lane SDRAM D & A bus, 33ohm resistors. eMMC Data lines, 22ohms serial resistors. Is the argument for the resistors to reduce "ringing" in lane ?

[BHell.1]

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[Peter BENSCH]

These resistors realize the termination to match the line impedance to the MCU. You can find various application notes as well as considerations like e.g. on Stackexchange.

Does it answer your question?

Regards

/Peter

[BHell.1]

Thank you! Great.

[Peter BENSCH]

You're welcome!

If the problem is solved, please mark this thread as answered by selecting Select as best, as also explained here. This will help other users find that answer faster.

Good luck!

/Peter