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CC1312R7: RAM requirement from ROM code

Part Number: CC1312R7
Other Parts Discussed in Thread: CC1354P10,

Tool/software:

Hi,
We recently added secure boot capabilities to a custom bootloader implementation and have a common implementation for CC1312 R1/R7 and CC1354 R10
In the existing BIM there is a comment in regards of RAM requirements from ECC ROM functions
Below snippet is from simplelink_cc13xx/source/ti/common/cc26xx/ticlang/bim_cc26x2_cc13x2.cmd

/* Reserved RAM is that section of the RAM used by the ROM code.

* For Secure BIM, the ECC library from ROM uses 0x80 bytes of
* RAM space at the beginning of the RAM.
*/
#define RESERVED_RAM_SIZE (0x300)

Besides comments in a linker script, I cannot find any documentation about these requirements.
Is this documented elsewhere and are there similar requirements from other ROM functions?
BR
  • Hi Martin,

    It will be different matter depending on the device.

    For the CC1354P10:

    • It does not have as many functions in ROM as the previous devices (so no ECC lib in ROM), see docs/driverlib/cc13x4_cc26x4/driverlib/rom_8h.html, and does not support BIM. This means that this comment does not apply.

    For the CC1312R7:

    • There is actually an updated comment in bim_cc26x2x7_cc13x2x7.cmd...
    • And you can actually see that the beginning of the RAM is being used by the ECC driver here: docs/driverlib/cc13x2x7_cc26x2x7/driverlib/group__rom__crypto__api.html

    Regards,

    Arthur

  • You're correct, I use ECDSACC26X4_driverlib.c for the 1354 platform.

    I didn't find any explicit documentation on docs/driverlib/cc13x2x7_cc26x2x7/driverlib/group__rom__crypto__api.html

    Perhaps you refer to the inline expansion of ECC_INIT indicating RAM memory range i.e. 

    *((uint8_t *)0x20000148) = windowSize;

    A bit implicit, but that implies I'm safe with the 0x300 offset, thanks!