RE: FDS NO_SWAP error - no swap pages

sihan chen — Wed, 15 Jul 2020 10:55:36 GMT

Hi All,

Can someone provide me a sample code for rebuild the SWAP page ID, Many thanks.

RE: FDS NO_SWAP error - no swap pages

sarah_sdw — Thu, 30 Jan 2020 15:30:17 GMT

Same error with sdk15.3. resolved with this, thank !

RE: FDS NO_SWAP error - no swap pages

aodonnell — Mon, 20 Jan 2020 19:56:01 GMT

This worked great, thank you!

RE: FDS NO_SWAP error - no swap pages

Jared — Mon, 20 Jan 2020 13:33:13 GMT

Hi,

[quote user=""]Even without knowing the exact cause, it would be great to be able to implement recovery when this error code is returned. I know that means erasing a page and then reinitializing, but I can't seem to figure out how to erase the correct "page number" using sd_flash_page_erase.[/quote]

You would have to iterate page for page through the flash looking for an empty data page that hasn't been written to yet. You can do this by making a new function that is similar to the page_can_tag function but starts to check the page data after the page tag:

static bool page_can_tag2(uint32_t const * const p_page_addr)
{
    // This function should consider pages that have only the first half
    // of the fds page tag written as erased (taggable).
    // That is because the tag is two words long, and if the device
    // has rebooted after writing the first word, that would cause
    // the page to be unusable (since undefined and not fully erased).
    // By considering the first word as erased if it contains fds page tag,
    // the page can be re-tagged as necessary.

    if ((p_page_addr[FDS_PAGE_TAG_WORD_0] != FDS_ERASED_WORD) &&
        (p_page_addr[FDS_PAGE_TAG_WORD_0] != FDS_PAGE_TAG_MAGIC))
    {
        return false;
    }

    // Ignore the tag and check if the rest of the page is written or not
    for (uint32_t i = FDS_PAGE_TAG_SIZE; i < FDS_PAGE_SIZE; i++)
    {
        if (*(p_page_addr + i) != FDS_ERASED_WORD)
        {
            return false;
        }
    }

    return true;
}

You can call this function for each data page and see if it has been written to or not. If it hasn't then you can delete it and reset the chip which will cause the system to promote the page to a swap page.

regards

Jared