How store large amount data 73Kbytes into flash using FDS?

[vishal]

We are using nRF52840 with sdk 15.0 version & segger embedded studio. We are able to store some small amount of configuration data into flash using FDS. But now we want to store large data array near about 73Kbytes into flash. I am writing example code for storing this data and created one dummy array of size 73728 bytes. But I getting following ERROR:

FDS_ERR_RECORD_TOO_LARGE

I am confused for configuration of FDS for storing 73Kbytes 

Here is bellow edited in sdk_config.h

FDS_VIRTUAL_PAGES 10

FDS_VIRTUAL_PAGE_SIZE 2048

FDS_OP_QUEUE_SIZE 4

Will you please help me how i use this above configuration for storing 73KB data. & how i fixed FDS_ERR_RECORD_TOO_LARGE ERROR?

Is it possible to store this data in one fds_record_write (...) call request?

Thanks in advanced..!!

[Ashish]

The number that you give for the FDS_VIRTUAL_PAGE_SIZE is actually 4-byte words. So you can save at a maximum of (2048-5)*4 = 8172 bytes. So you will need to split up your data if you want to save more than that.

[vishal]

Ok, Is it possible to increase FDS_VIRTUAL_PAGE_SIZE as per required data storage above of 2048. If i increase this i got ERROR 11 i.e. NRF_ERROR_INVALID_DATA when fds_flash_init();

We will split our data with smaller chunks with multiple of above maximum limit. But still confused for is it needed to change record key every request of that.

here is bellow my sample code snippet for storing dummy array of 73728bytes.

 

void fds_data_write() {
  uint32_t length = 74000;
  uint8_t data_write[length];
//  memset(data_write,2,sizeof(data_write));
  for (int i = 0; i<=length; i++) {
   data_write[i] = i;
  }
//  NRF_LOG_INFO("fds_data_write");
  ret_code_t ret = fds_write(FILE_ID_READING_1, REC_KEY_READING_1,(char *)data_write,length);
  if (ret == FDS_SUCCESS) {
    NRF_LOG_DEBUG("FDS data stored");
  } else {
    NRF_LOG_DEBUG("FDS failed error code:%d", ret);
  }
}

Will you please provide me program snippet for how i call multiple request for storing 73KB data with FILE-ID and REC_KEY. Because after stored this data we want to also retrieve this data as required time.

Lets say from above whole array first 8172 bytes stored of 1 request with specific FILE_ID & RECKEY, Then i should need to call next chunk data for that is it necessary to change RECKEY.

Because if KECKEY is not change for second call request it will overwritten data on old. Is any other way to store this large data with one FILEID & KECKEY?

Thanks.....

[vishal]

Thanks Ashisk,

Now we are able to store 74 KB data in flash also read this data, but got one issue for wait_for_write(); function. My program is not work when mobile application is connected wit device that time want to write data into flash. Because it continuous on this loop not triggering FDS_EVT_WRITE event, since this flash is not true. This happening only when BLE is connected to phone. If phone is not connected then is working and also trigger FDS event. 

We still stuck here why this happening with BLE connection established and still it connected that time only FDS write event is not trigger.

Thanks..

[Ashish]

Hey Vishal,

A couple of things:

Are you using the nrf_fstorage_sd.c library or nrf_fstorage_nvmc.c? You should be using the former one with softdevice enabled. 

In sdk_config.h, FDS_BACKEND should be 2 to work with softdevice.

Can you check what is the return value that you are getting in case when FDS_EVT_WRITE doesn't give FDS_SUCCESS?

Are you calling the fds write function in another callback or another handler?

[vishal]

Thanks for fast reply,

Actually i am using ble_app_uart example and modified this example as per our application with FDS library.

Ashish said:

Are you using the nrf_fstorage_sd.c library or nrf_fstorage_nvmc.c? You should be using the former one with softdevice enabled. 

Yes i am using nrf_fstorage_sd.c lib 

I checked in my sdk_config.h FDS_BACKEND  is 2.

The return value is 0 when but not trigger FDS_EVT_WRITE.

I am calling fds write function in nus_data_handler(...); something command received from mobile app.

But when i comment wait_for_write();function that time it working..

what happening with ble connected for fds event???

Thanks....

[awneil]

So don't sit in a blocking loop waiting for the event - handle it asynchronously.

[vishal]

Means what not understand properly, Will you please explain in little bit more

awneil said:

don't sit in a blocking loop waiting for the event

Thanks..

[Ashish]

Hey,

You should not be waiting for an event inside the nus_data_handler.

Either start the write from the main context by setting a flag variable or don't wait for the event in a blocking loop(wait_for_write).

Check here for more info