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AM6548: Sigrity SystemSI simulation with LPDDR4 memories

Zoran Dukic
Prodigy 155 points
Part Number: AM6548


Hi all,

I went through the Sygrity SystemSI simulations of an existing system that contains Sitara AM6548 and LPDDR4 memory (Micron MT53E128M32D2DS-046 AAT:A or ISSI IS46LQ32128A-062BLA2). For LPDDR4 memories suggested Ibis models are used. For Sitara AM6548 models from the last sheet within AM65x_DRA80xM_EMIF_Tool_2.02 are used. So, for Sitara:

Suggested Models to Use  
Clock Driver DWC_D5MC4_48_SR11 
Addr/Cmd/Ctrl Driver DWC_D5MP4_48_SR11    
Data Receiver DWC_D5MP4_34ODT48    
Data Driver DWC_D5MP4_48_SR11    
DQS Receiver DWC_D5MQ4_34ODT48       
DQS Driver DWC_D5MQ4_48_SR11       

For Sitara AM6548 the AM6548 IBIS Model SPRM723_v0p1.ibs is used.

During the read cycle everything works well and the voltage levels are OK for both memories:

We have an issue with voltage levels regardless of the memory model being used for simulation during the write cycle on DQx and DQSx lines and with AddrCmd and Ctrl lines. Simply speaking the voltage levels are too high. 

  

Can you confirm that the suggested Sitara Ibis models are the right ones?  

Best regards,

Zoran Dukic

  • 0
    Prodigy 155 points

    Sorry,

    in the previous post, the suggested Ibis models were not correctly copied from the EMIF tool. The suggested values from the EMIF tool are:

    Suggested Models to Use  
    Clock Driver DWC_D5MCL4_48_SR11  
    Addr/Cmd/Ctrl Driver DWC_D5MPL4_48_SR11   
    Data Receiver DWC_D5MPL4_96ODT48   
    Data Driver DWC_D5MPL4_48_SR11   
    DQS Receiver DWC_D5MQL4_96ODT48        
    DQS Driver DWC_D5MQL4_48_SR11        
  • 0 in reply to Zoran Dukic
    TI__Guru* 89665 points

    Zoran, it looks like you have 48ohm driver set for AM65x.  What it the memory ODT setting in this case?

    Regards,

    James

  • 0 in reply to JJD
    Prodigy 155 points

    James,

    Thanks for the reply. 

    48ohm setting is used for the memory ODT, also. Btw, the impedance of PCB traces is 45ohms for single-ended or 90ohms for differential traces.

    Best regards,

    Zoran

  • 0 in reply to Zoran Dukic
    TI__Guru* 89665 points

    Zoran, Have you tried other ODI/ODT combinations?    

    Regards,

    James

  • 0 in reply to JJD
    Prodigy 155 points

    James,

    The only combinations tried are from the last sheet in the EMIF Excel table. I'm not sure what is the meaning of the SR01, SR10 and SR11 combinations in the IBIS model names? It's easy with the LPDDR4 memory IBIS models since the model names match the requested ODT values. With AM65x IBIS models there are several possibilities.

    Regards,

    Zoran

  • 0 in reply to Zoran Dukic
    TI__Guru* 89665 points

    The SR** refer to the slew rate setting (these are set on the first page of the spreadsheet).  SR11 is the fastest down to SR00 is the slowest.  You can try to slow down the edge rate to see if you get better results.  

    The suggested IBIS models will change based on the values on the first page of the spreadsheet (slew rate, ODI, ODT), so you don't have to decode all the model names

    Regards,

    James