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Hi all

Vu Diep
Prodigy 185 points

Other Parts Discussed in Thread: MSP430FG4619

I'm using msp430fg4619. I have one question. Is msp430 support RAM external? what msp430 family is supported RAM external?

Thank you very much.

  • 0
    TI__Guru 64820 points

    None of the MSP430 devices have a memory controller interface that would allow direct connection to an external memory with a SRAM like interface.

  • 0 in reply to BrandonAzbell
    Prodigy 185 points

    Thank BrandonAzbell. But I read msp430fg4619 datasheet, at 16 page. Total RAM of Msp430 equal 4k include: 2k Extended and 2k Mirrored. Could you like to explain for me.

    Thank you.

  • 0 in reply to Vu Diep
    TI__Guru 64820 points

    I would agree it is a bit confusing and it took me a minute to comprehend what is being illustrated.

    The MSP430FG4619 has 4K bytes of RAM total on the device (ie. integrated on-chip).

    2K bytes @ 0x0200 through 0x09FF  (this is mirrored @ 0x1100 through 0x18FF)
    2K bytes @ 0x1900 through 0x20FF

  • 0 in reply to Vu Diep
    Guru 227245 points

    Mirrored RAM happens, if an MSP has more ram than his smaller brothers, yet needs this ram to be moved to a different address because on the original address is not enough space for the whole amount. Then part of this ram is mirrored to the original location, so that the MSP is binary backwards compatible to the smaller MSPs.

    In case of the 4619, from the 4k RAM (which are located on the area 0x1100-0x20ff), the lower 2k are mirrored to the area 0x0200-0x09ff where some smaller MSPs have their 2k ram. Since right above this area the boot memory is located, the ram couldn't be just enlarged.
    Since the ram should be in a continuous block, it had to be moved. Yet part of it is mirrored to the 'old' location, so code written for the smaller MSP will also run on the bigger one, which has the same (and more) hardware modules, ports etc, so it can be used as replacement.

    There is, however, no externally available data or address bus, so no external ram can be attached to the MSP (other than under program control as 2nd level memory like SD card or HD or whatever.)

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