How to use FDS for reading and writing data?

RE: How to use FDS for reading and writing data?

purgoufr — Tue, 20 Mar 2018 08:10:56 GMT

Writing and reading operations using FDS are solved in the following link.

RE: How to use FDS for reading and writing data?

purgoufr — Fri, 02 Mar 2018 08:38:39 GMT

How can I do data storing or printing without using CLI? Because I do not want to print data or anything else. I only want to store the data in an array that I write with fds_write.

I wil try to explain what I need;

Write " uint8_t a[4] = { 'a', 'b', 'c', '\0' }; " this array via FDS write
Read "a[4]" from FDS
Store "a[4]" into uint8_t "b[4]" ;
The value of the b[4] (read_data) should print like this ; NRF_LOG_HEXDUMP_INFO(b, sizeof(b));

Result must be;

0> <info> app: 61 62 63 00 |abc.

I want to do all of this without using cli.

RE: How to use FDS for reading and writing data?

MartinBL — Wed, 28 Feb 2018 10:58:19 GMT

I'm still a little confused about the flow in your code. How about something like this:

uint8_t * pointer_to_record_data;
pointer_to_record_data = (uint8_t *)frec.p_data;

uint8_t test_data_0[10];

if(frec.p_header->record_key == A_RELEVANT_RECORD_KEY)
{
    for(uint8_t i = 0; i < 10; i++)
    {
        test_data_0[i] = *pointer_to_record_data;
        pointer_to_record_data++;
    }
}

to get the record data stored in your array.

RE: How to use FDS for reading and writing data?

purgoufr — Tue, 27 Feb 2018 11:21:24 GMT

Thank you so much for your solution. But I have to store data into uint8_t array[10]. It means, I want to write "abcdefghij" via nus_data . I can do this shown as below, there is no problem.

0> <info> app: save_data
0> <info> app: Writing Record ID = 1
0>
0> 61 62 63 64 65 66 67 68|abcdefgh
0> 69 6A |ij

Then I want to read "abcdefghij" and store it in uint8_t array [10].

That's why I figure out your "convert_raw_data_to_human_readable" function as below:

static void convert_raw_data_to_human_readable(uint8_t *out_data , uint32_t in_data)
{
    for(uint8_t i = 0; i < 4; i++)
	{
		out_data[i] = (uint8_t)(in_data >> (8 * i));
    }
}

And I put the function inside kls_fds_read() function like this;

uint32_t *data     = (uint32_t *) flash_record.p_data;
uint32_t const len = flash_record.p_header->length_words * sizeof(uint32_t);
				
for(uint32_t i; i < len / 4; i++)
{
    convert_raw_data_to_human_readable(read_data, *data);
    data++;
}

Finally, I'm trying to write on my destination array(dest_data_0[10]);

static void first_Setup(void)
{
	NRF_LOG_INFO("first_Setup Start");
	uint8_t dest_data_0[10]  = {0};

	
	while (flag_write_fds == 0);
	kls_fds_read(FILE_ID, RECORD_KEY, dest_data_0);
}

But I did not get the data I wrote.

RTT Viewer output:

0> <info> app: first_Setup Start

0> <info> app: Found Record ID = 1
0>
0> <info> app: Data =
0> <info> app: dest_data_0 :
0> <info> app: 00 00 00 00 00 00 00 00|........
0> <info> app: 00 00 |..

RE: How to use FDS for reading and writing data?

MartinBL — Tue, 27 Feb 2018 09:37:59 GMT

Printing is done in print_data_cmd() in cli.c.

RE: How to use FDS for reading and writing data?

MartinBL — Tue, 27 Feb 2018 09:36:20 GMT

I got carried away and made an example. I based it on the Flash Data Storage Example and changed cli.c and main.c a little so that you can print out record details as well as the actual data. Use the Command Line Interface library to write and print records. Have a look at the attached files to see the changes I made and how it can be done.

devzone.nordicsemi.com/.../main.c

devzone.nordicsemi.com/.../main.diff

devzone.nordicsemi.com/.../cli.c

devzone.nordicsemi.com/.../cli.diff

RE: How to use FDS for reading and writing data?

purgoufr — Tue, 27 Feb 2018 07:37:32 GMT

Yes, you are exactly right. Because

void const * p_data; //!< Location of the record data in flash.

It means, I read the location, not Data itself. So how can I read Data itself?

RE: How to use FDS for reading and writing data?

purgoufr — Tue, 27 Feb 2018 06:08:20 GMT

I tried to fds_write uint8_t some_array[10] variable. Then I tried to read same array which has uint8_t type. But data is equal to (uint32_t *) flash_record.p_data . I think it is not avaliable for uint8_t type variable. So, How to save array that is uint8_t type variable and how to read the same array.

RE: How to use FDS for reading and writing data?

purgoufr — Mon, 26 Feb 2018 13:59:05 GMT

Hi Martin,

I printed like this;

static void first_Setup(void)
{
    NRF_LOG_INFO("first_Setup Start");
    uint8_t dest_data_0[10]  = {0};
	
	while (flag_write_fds == 0);
	kls_fds_read(FILE_ID_SSN, RECORD_KEY_SSN, dest_data_0);
	
	NRF_LOG_INFO("dest_data_0 : ");
	NRF_LOG_HEXDUMP_INFO(dest_data_0, 10);
}

I wrote the function "kls_fds_read" at the top, you can look at it from there. In a part of "Kls_fds_read" function I used this code to print out;

NRF_LOG_INFO("Found Record ID = %d\r\n",record_desc.record_id);
NRF_LOG_INFO("Data = ");
				
data = (uint32_t *) flash_record.p_data;
for (uint8_t i=0;i<flash_record.p_header->length_words;i++)
{
	NRF_LOG_INFO("0x%8x ",data[i]);
	read_data[i] = data[i] ; 
}
NRF_LOG_INFO("\r\n");

data = (uint32_t *) flash_record.p_data; ------>>>> Does not that mean the data itself?

I try to read data with use "uint8_t read_data" but fds used "uint32_t *data;" , and I try to copy the data into read_data via "read_data[i] = data[i] ; ". Although I do not get any errors, maybe it is not logical to choose two different variable types.

RE: How to use FDS for reading and writing data?

MartinBL — Mon, 26 Feb 2018 12:30:48 GMT

Can you show us how you print out your data? And maybe post more of your code?

Values like 0x20005CC8 look like addresses in RAM, so it might be that you are simply printing out the location of your data, and not the data itself.