About Vtt termination in i.MX6SDL.

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About Vtt termination in i.MX6SDL.

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keitanagashima
Senior Contributor I

Dear Sir or Madam,

Hello.

I have a question about Vtt termination in i.MX6SDL.

[Question]

[Q1]

Refer to "3.5.5 4-Gigabyte recommendations" and "Figure 3-12. ADDR/CMD signal topology" in IMX6DQ6SDLHDG(Rev.1).

Tehere is description of "This option has eight DDR3 memories and requires the addition of a termination resistor."

Is VTT termination necessary to four DDR3 memories, too?

If one change from i.MX6DL to i.MX6Q (i.e. DDR clock 400MHz to 528MHz), is VTT termination necessary to four DDR3 memories, too?

[Q2]

Refer to "Figure 3-13. CTRL signal topology".

Is this figure at the eight DDR3 memories?

Is VTT termination necessary to four memories, too?

Best Regards,

Keita

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Yuri
NXP Employee
NXP Employee


   Use the VTT termination of the DDR3 bus if more than 4 external memory chips and fly-by

routing topology is used. If no more than 4 external DDR3 chips is present and T-type routing

topology is used, the VTT termination is not required.


Have a great day,
Yuri

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Yuri
NXP Employee
NXP Employee


   Use the VTT termination of the DDR3 bus if more than 4 external memory chips and fly-by

routing topology is used. If no more than 4 external DDR3 chips is present and T-type routing

topology is used, the VTT termination is not required.


Have a great day,
Yuri

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Note: If this post answers your question, please click the Correct Answer button. Thank you!
-----------------------------------------------------------------------------------------------------------------------

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keitanagashima
Senior Contributor I

Hi Yuri,

Thank you for your prompt reply.

I understood that VTT termination is not required on the 4 external memories with T-type routing topology.

Both of ADDR/CMD and CTRL signal are same recommendation, aren't these?

BR,

Keita

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Yuri
NXP Employee
NXP Employee

Yes.

~Yuri

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keitanagashima
Senior Contributor I

Hi Yuri,

Thank you!

BR,

Keita

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