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[OMAP3530] Public vs Secure Memory?

Greg Jackson
Prodigy 10 points
Other Parts Discussed in Thread: OMAP3530

While looking through the block diagram in the OMAP3530 documentation, I noticed that both the RAM and ROM list both 'public' and 'secure' memory ('64K on-chip RAM 2KB public/ 62KB secure' and '112K on-chip ROM 80KB secure/ 32KB BOOT'). I can guess what the boot ROM might be, but I haven't had any luck finding the difference between 'public' and 'secure' memory, either in general, or in reference to the OMAP3530. 

Could anyone enlighten me as to this difference, or provide a pointer to some resources that would help me with this?

  • 0
    Prodigy 10 points

    In General, the OMAP security heavily relies on the ROM CODE which is the trusted and the only reliable code for security purpose.
    ROM memory is divided into two regions, Public and Secure.One can define secure RAM or ROM like below

    Secure RAM: Writable area of the On Chip Memory (RAM). Protected applications are loaded for execution and
    secure data is temporarily stored in this area. Can only be accessed when the processor is in secure
    mode, or by a secure DMA channel.
    Secure ROM: Read-only memory inside the chip. Programmed at the chip manufacturing phase. Can
    be accessed only when the processor is in secure mode.
    Generally, Public ROM code starts when secure ROM code finishes its start-up procedure.
    Public RAM is for Normal RAM.

    One can find some info on Secure and Public memory in "Memory Subsystem" Chapter in 35xx TRM.
    Link for it is given below.
    http://focus.ti.com/lit/ug/spruf98d/spruf98d.pdf

  • 0 in reply to Kedar Kulkarni
    Prodigy 30 points

    So I am gathering, in order to get a high security version of the OMAP it must be custom manufactured?  I am trying to find one has high security enabled but all of the models listed are marked general purpose.