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AM3352: AM3352 substituting with AM3354/6/8

Blake Carpenter
Expert 6975 points
Part Number: AM3352
Other Parts Discussed in Thread: AM3354

All, 

I have 2 focus customers looking to substitute AM3354/6/8's for the AM3352 for part availability.

While it looks easy (if matching temperature and package), the devil is in the details.

I assume there is a product ID that might have to be added to the firmware if their firmware team has accessed it.

One customer brought up speed grades and noted that Linux would try and run at the fastest speeds so if a 3358 1GHz part was substituted Linux would run faster than their thermal envelope at 800MHz on the 3352.

This doesn't sound right to me - but the datasheet was ambiguous.

Thoughts on pitfalls to watch for?

Thanks!

Blake

  • 0
    TI__Mastermind 27975 points

    Blake 

    I have put together a generic guide for the AM335x substitutions.  

    --Paul

    AM335x device substitutions, things to consider. 

    Power

    When substituting a device with a device that contains additional features, you should see not increase in power as these features power up in a reset state and must be activated by software before they will consume power.

    This applies to the 3D GPU and Industrial protocols.

    See Table 8-28. Power Domain State Table  in the TRM for details of Reset States.

    Features

    The DEV_FEATURE register will be different for different AM335x devices.

    This register can be used to determine which part is installed in a system.  If your system software uses this register to identify the processor, you will need to confirm that the change in value will not impact the operation of you system.

     

    The DEV_FEATURE value for each device can be found at the bottom of the device comparison table in the AM335x datasheet.

    You can use a device with additional features as a substitute. However, If you need a feature such a GPU, you cannot substitute a device that does not support that feature.

     

    Speed Grade

    You can substitute a faster speed grade in place of a lower grade device.  You cannot substitute a lower speed grade for a faster device unless you are running at, or below the maximum speed of the substituted device.

    The maximum speed of a device can be read from the efuse_sma register, see table 9-59 of the TRM for details.   If your software hard-codes the maximum device frequency then differences in this register will not impact your system.

    However, if you s/w sets the maximum frequency based on this register, then you may encounter issues with the processor running faster than expected.  

     

    Temp Grade

    You should not substitute a device with a lower temp grade device.  This is true, even if you are substituting a faster speed grade at a lower speed.

     

    Package

    The substitute device must be the same package type. You cannot use a ZCZ in a ZCE application, nor can you use a ZCE in a ZCZ application.