Writing/reading data to external flash on the nRF9160DK

[nWre]

Hello Nordic!

I have connected a sensor to the DK via SPI. It outputs a lot of data, a lot... for 1 second of data I get 4096 entries. Each entry is 10 bytes in length.

I want to store 20 seconds of sensor data on the flash memory, that is a total of about 0,8 MB if my calculations are correct.

The sensor has a FIFO-queue so if the write operation is quick enough there shouldn't be any data loss.
Once 20 seconds worth of data is recorded I then want to send this via LTE to server, I'm guessing in chunks.

Questions:
* How do I go about this? Is there a binary write example available?

* What size should the chunks be for this example?

* Once a file is written and done, before going in to the LTE-part of the design, is there any way to extract the bin file for data validation from the DK?

Thank you!

[nWre]

Hi Sebastiaan! Thank you for answering, truly appreciate it! I was to understand that the nRF9160DK has a 64 Mb external flash memory described here:
https://infocenter.nordicsemi.com/index.jsp?topic=%2Fug_nrf91_dk%2FUG%2Fnrf91_DK%2Fexternal_memory.html

This is indeed done via SPI.

I'm thinking http communication but that is mostly because it's the one I know and have used, does it make much of a difference?

That's a clever solution for getting the data, I will look into that solution.

Many thanks!

[Håkon Alseth]

Since you mention using the nRF9160DK's external flash, it is important that you switch in the lines for the external flash. That is done by re-programming the board controller, with the sequence explained here:

https://devzone.nordicsemi.com/f/nordic-q-a/80836/extend-flash-size-of-nrf9160---single-slot-application/335345#335345

 

create the file my_project/pm_static.yml, which holds something like this (alter sizes to your needs):

settings_storage:
  address: 0x0
  region: external_flash
  size: 0x40000

 

Kind regards,

Håkon

[Håkon Alseth]

Hi nWre!

 

nWre said:

Hi again Håkon! Hoppas allt är bra med dig!

All good here, thanks! Hope you had a wonderful trip!

 

nWre said:

I've flashed the sequence you linked earlier with the prog/debug-switch on nrf52:

nWre said:

I've also added the SPI-code that you linked:

 

The "board-control" is setting a pin on the nRF52840 on the DK to route the ext-flash to the nRF91, while the next is a direct setting of which nRF9160 GPIO on the is connected to the /CS pin on the external-flash itself.

 

They should match the hardware layout of the nRF9160-DK, which they do by default.

 

nWre said:

Now that this config is done, should I be able to use say, LittleFS to write to the external memory by pointing it towards the MX25R64 in the device tree? Is there any other config I should do?

Define it in your pm_static.yml, here from addr offset 0, size 256kB in region "external_flash":

littlefs_storage:
  address: 0x0
  device: MX25R64
  end_address: 0x40000
  region: external_flash
  size: 0x40000

 

Remember to re-generate your build after altering the pm_static.yml!

 

Kind regards,

Håkon

[nWre]

Seems like the namespace littlefs_storage is not accepted when I try to build the project. I get this:

'PM_littlefs_storage_ID' undeclared here (not in a function); did you mean 'littlefs_storage'?

I'm trying to use the example from Zephyr

/* Matches LFS_NAME_MAX */
#define MAX_PATH_LEN 255

#define PARTITION_NODE DT_NODELABEL(mx25r6435f)

#if DT_NODE_EXISTS(PARTITION_NODE)
FS_FSTAB_DECLARE_ENTRY(PARTITION_NODE);
#else  /* PARTITION_NODE */
FS_LITTLEFS_DECLARE_DEFAULT_CONFIG(storage);
static struct fs_mount_t lfs_storage_mnt = {
	.type = FS_LITTLEFS,
	.fs_data = &storage,
	.storage_dev = (void *)FLASH_AREA_ID(storage),
	.mnt_point = "/lfs",
};
#endif /* PARTITION_NODE */

void memtest(void)
{
	struct fs_mount_t *mp =
#if DT_NODE_EXISTS(PARTITION_NODE)
		&FS_FSTAB_ENTRY(PARTITION_NODE)
#else
		&lfs_storage_mnt
#endif
		;
	unsigned int id = (uintptr_t)mp->storage_dev;
	char fname[MAX_PATH_LEN];
	struct fs_statvfs sbuf;
	const struct flash_area *pfa;
	int rc;

	snprintf(fname, sizeof(fname), "%s/boot_count", mp->mnt_point);

	rc = flash_area_open(id, &pfa);
	if (rc < 0)
	{
		printk("FAIL: unable to find flash area %u: %d\n",
			   id, rc);
		return;
	}

	printk("Area %u at 0x%x on %s for %u bytes\n",
		   id, (unsigned int)pfa->fa_off, pfa->fa_dev_name,
		   (unsigned int)pfa->fa_size);

	/* Optional wipe flash contents */
	if (IS_ENABLED(CONFIG_APP_WIPE_STORAGE))
	{
		printk("Erasing flash area ... ");
		rc = flash_area_erase(pfa, 0, pfa->fa_size);
		printk("%d\n", rc);
	}

	flash_area_close(pfa);

	/* Do not mount if auto-mount has been enabled */
#if !DT_NODE_EXISTS(PARTITION_NODE) || \
	!(FSTAB_ENTRY_DT_MOUNT_FLAGS(PARTITION_NODE) & FS_MOUNT_FLAG_AUTOMOUNT)
	rc = fs_mount(mp);
	if (rc < 0)
	{
		printk("FAIL: mount id %u at %s: %d\n",
			   (unsigned int)mp->storage_dev, mp->mnt_point,
			   rc);
		return;
	}
	printk("%s mount: %d\n", mp->mnt_point, rc);
#else
	printk("%s automounted\n", mp->mnt_point);
#endif

	rc = fs_statvfs(mp->mnt_point, &sbuf);
	if (rc < 0)
	{
		printk("FAIL: statvfs: %d\n", rc);
		goto out;
	}

	printk("%s: bsize = %lu ; frsize = %lu ;"
		   " blocks = %lu ; bfree = %lu\n",
		   mp->mnt_point,
		   sbuf.f_bsize, sbuf.f_frsize,
		   sbuf.f_blocks, sbuf.f_bfree);

	struct fs_dirent dirent;

	rc = fs_stat(fname, &dirent);
	printk("%s stat: %d\n", fname, rc);
	if (rc >= 0)
	{
		printk("\tfn '%s' siz %u\n", dirent.name, dirent.size);
	}

	struct fs_file_t file;

	fs_file_t_init(&file);

	rc = fs_open(&file, fname, FS_O_CREATE | FS_O_RDWR);
	if (rc < 0)
	{
		printk("FAIL: open %s: %d\n", fname, rc);
		goto out;
	}

	uint32_t boot_count = 0;

	if (rc >= 0)
	{
		rc = fs_read(&file, &boot_count, sizeof(boot_count));
		printk("%s read count %u: %d\n", fname, boot_count, rc);
		rc = fs_seek(&file, 0, FS_SEEK_SET);
		printk("%s seek start: %d\n", fname, rc);
	}

	boot_count += 1;
	rc = fs_write(&file, &boot_count, sizeof(boot_count));
	printk("%s write new boot count %u: %d\n", fname,
		   boot_count, rc);

	rc = fs_close(&file);
	printk("%s close: %d\n", fname, rc);

	struct fs_dir_t dir;

	fs_dir_t_init(&dir);

	rc = fs_opendir(&dir, mp->mnt_point);
	printk("%s opendir: %d\n", mp->mnt_point, rc);

	while (rc >= 0)
	{
		struct fs_dirent ent = {0};

		rc = fs_readdir(&dir, &ent);
		if (rc < 0)
		{
			break;
		}
		if (ent.name[0] == 0)
		{
			printk("End of files\n");
			break;
		}
		printk("  %c %u %s\n",
			   (ent.type == FS_DIR_ENTRY_FILE) ? 'F' : 'D',
			   ent.size,
			   ent.name);
	}

	(void)fs_closedir(&dir);

out:
	rc = fs_unmount(mp);
	printk("%s unmount: %d\n", mp->mnt_point, rc);
}

Önsker deg en nydelig helg!

[Håkon Alseth]

Hi,

 

Here's a modified littlefs sample, with nrf9160dk ext flash support:

ncs1_7_nrf9160dk_ext_flash_littlefs.zip

 

Kind regards,

Håkon

[nWre]

Thanks Håkon, I tried the sample but having trouble with the SPI-bus. "Node should only occur on the spi bus", I'm guessing that occurs because the sample you sent does not have a

compatible = "nordic,nrf-spim";

If I do include that, I instead get these errors:



Thank you for all the help, you are my Gandalf in Moria.

[Håkon Alseth]

Hi,

 

The "compatible" member shall be inherited from the board itself, ie. this line:

https://github.com/nrfconnect/sdk-zephyr/blob/main/boards/arm/nrf9160dk_nrf9160/nrf9160dk_nrf9160_common.dts#L197

 

Which board are you configuring for? It should be the "nrf9160dk_nrf9160_ns" board.

 

PS: remember to delete any ancient build folders, especially when editing static partition layout.

 

Kind regards,

Håkon

[nWre]

Yes, building for the "nrf9160dk_nrf9160_ns" board. Using the sample with the correct board setup I still get the same errors I posted above. Are you able to run the sample without any mods on nrf9160dk? If that's the case I might need to do a reset. Thanks again, appreciate it.

Edit: The reset helped, I must have written something goofy somewhere. Thanks Håkon, you the man. I'll buy you a beer if you ever come to Gothenburg.