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SM320F28335-EP: Dual-mapped memory region

Jaiganesh Jayaraman76473
Prodigy 250 points

Part Number: SM320F28335-EP

Hello,

As per F28335 memory map, Memory locations 0x008000 to 0x00C000 (16K words) and memory locations 0x3F80000 to 0x3FC000 are 'Dual-Mapped'. In this case, can memory be allocated to both these regions?

Memory

{

Page 0:

APP_ROM       : origin = 0x3000AC, length = 0xA500

RAMH1 : origin = 0x3F8000, length = 0x002000

Page 1:

/* Data memory */
L0L1L2L3RAM(RW) : origin = 0x008000, length = 0x4000

}

SECTIONS
{

.ebss               : > L0L1L2L3RAM, PAGE = 1

 APPRAMFUNC : > APP_ROM, PAGE = 0,
 RUN = RAMH1,
 LOAD_START(_APP_RAM_FUNC_LOAD_START),
 RUN_START(_APP_RAM_FUNC_RUN_START),
 SIZE(_APP_RAM_FUNC_SIZE)

}

Please help. 

Thanks,

Jaiganesh

  • 0
    TI__Guru 61235 points

    Jaiganesh,

    The dual mapping means that the memory appearing at addresses 0x8000 to 0xBFFF is the same physical memory as that appearing at 0x3F8000 to 0x3FBFFF.  For example, if you wrote the value 0x1234 to location 0x8000, you could read 0x1234 from address 0x3F8000.

    So no, you cannot store different values to these dual mapped locations.

    Regards,

    David

  • 0
    TI__Guru* 93800 points

    Hello, 

    This is the same physical memory.  Pick one location or the other to use, but not both.  If you use both it will only write over the other location.  

    PS: The dual-mapping was for a compatibility mode with old LF240x processors. 

    Regards

    Lori