How to use all 1.5 MB RAM instead of default 768KB



  • In the documentation it says:
    "The maximum RAM available is 768 kilobytes (= 786432 bytes) by default. Which is half of the size of application SRAM of 1.5 MB."
    So how can I use all 1.5MB RAM in an Arduino sketch?


  • DeveloperWorld

    Hi @yokonav,

    The size of the RAM mounted on the Spresense mainboard is 1.5MB. But the operating system, Nuttx, needs a bit of this to be able to function properly. I think it is around 3-500kb that is consumed by Nuttx. Then the Arduino layer need a bit of the RAM too. Then there is the GNSS firmware that consumes some RAM too.
    So the full 1.5MB can't be used for an application.
    If you really need more ram for your sketch it should be possible to reconfigure the kernel and remove functions/drivers that aren't needed for your specific application.

    Hope this answer clarifies your question.

    BR
    Karl



  • Thanks for the clarification! Can we run bare-metal applications on Spresense (for example only Arduino)?


  • DeveloperWorld

    @yokonav my short answer with a bit of guessing is that this should be possible but it would be close to impossible to get certain parts to get to work, like GNSS that is provided as a binary.
    BR
    Karl


Log in to reply