NRF9160dk storing to and reading from flash

RE: NRF9160dk storing to and reading from flash

Andrey Dodonov — Thu, 19 Nov 2020 07:47:37 GMT

Nice answer!

Just please take into consideration that Zephyr is constantly under development, so API and libary locations might change, it is best to have a look at samples.

Currently good examples are under
/zephyr/samples/subsys/nvs
and
/nrf/lib/bin/lwm2m_carrier/os

For example, now I had to use different include paths for flash and nvs:

#include <drivers/flash.h>

#include <fs/nvs.h>

Also note that second parameter for nvs_write/nvs_read is currently not a memory offset, it is an ID.
For details see https://docs.zephyrproject.org/latest/reference/storage/nvs/nvs.html?highlight=nvs_write#c.nvs_write

Last, but not the least, depending where you are writing (e.g. I needed to write to inernal memory of NRF9160, I have custom layout),

CONFIG_MPU_ALLOW_FLASH_WRITE=y

Might be needed in your prj.conf

RE: NRF9160dk storing to and reading from flash

Jace — Fri, 27 Sep 2019 14:30:24 GMT

Wanted to point out something I noticed after posting this:

I name the return variable of the nvs read call "err" here, short for error. This could cause confusion because nvs_read returns the number of bytes read successfully and not an error code

RE: NRF9160dk storing to and reading from flash

Jace — Thu, 12 Sep 2019 20:58:16 GMT

I was able to figure it out. Zephyr has a library called NVS.

In my prj.conf I added:

CONFIG_FLASH=y
CONFIG_FLASH_PAGE_LAYOUT=y
CONFIG_NVS=y

and then my code looks like this:

#include <nvs/nvs.h>
#include <device.h>
#include <flash.h>


{

static struct nvs_fs fs;

struct flash_pages_info info;
fs.offset = DT_FLASH_AREA_STORAGE_OFFSET;
err = flash_get_page_info_by_offs(device_get_binding(DT_FLASH_DEV_NAME),
    fs.offset, &info);
if (err) {
    printk("Unable to get page info");
}
fs.sector_size = info.size;
fs.sector_count = 3U;
err = nvs_init(&fs, DT_FLASH_DEV_NAME);
if (err) {
    printk("Flash Init failed\n");
}

char wbuf[16];
char rbuf[16];
strcpy(wbuf, "Hello");
nvs_write(&fs, DT_FLASH_AREA_STORAGE_OFFSET, &wbuf, strlen(wbuf)+1);
err = nvs_read(&fs, DT_FLASH_AREA_STORAGE_OFFSET, &rbuf, sizeof(rbuf));
printk("%s", rbuf);

}