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TMS320F28388D: Layout guidelines to excess two devices SDRAM&Ethernet controller

Jan Hummel53
Intellectual 310 points

Part Number: TMS320F28388D

Hello,

I want to connect the EMIF to one SDRAM (IS45S16320F-7BLA2) and one Ethernet controller (LAN9221i).

The SDRAM should run with 100MHz

In the Manual https://www.ti.com/lit/an/sprac96a/sprac96a.pdf there is a short Layout Guidelines (chapter 3.3) for the EMIF.

I need a more details guideline for the layout.

What is the maximum length of the traces?

What is the maximum length for the stubs when branching off the main line?

How can you calculate the maximum skew for the SDRAM an Ethernet controller in order to get the tolerable length differences of the traces? Do all traces have the same length? Or is it possible to have some groups with the same length?

What kind of termination can you recommend? 50Ohm at the end? and 25 Ohm in series at the controller? for a trace impedance of 50 Ohm.  

Which traces should be separated?

Best regard

Jan Hummel


  • 0
    TI__Guru** 116081 points

    Hi Jan,

    Along with the appnote (which has reference design) you mentioned, we have timing information in datasheet and customer need to design their board accordance to that. We do not have any other recommendation on hardware design side.

    Regards,

    Vivek Singh