MPC5645S Queries

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MPC5645S Queries

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NXP Employee
NXP Employee

Hi,

   Customer has below queries. Pls help.

  1. Do we need to consider any internal package delays for the DDR2 pins when calculating the delay associated with a trace? 
  2. We are using an x16 DDR2 interface. So that there are unused pins in the DDR2 interface. There are GPIOs also unused. We haven't found any information in Hardware design documents regarding the state at which these unused pins need to be kept. Are they need to terminate to Ground or to kept floating?

Thanks,

Amit Gombi.

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NXP TechSupport
NXP TechSupport

Regarding delay I am not sure. Datasheet does not specify it. Are you calculating round trip delay or which parameter?

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NXP TechSupport
NXP TechSupport

Unused pins are recommended to be put in this configuration: Output buffer disabled, Input buffer disabled, Weak Pull Down enabled. So it may be left floating.

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