How to write, read and store uint8_t data_array via FDS

[purgoufr]

Hello everybody,

I used SDK14.2.0 , S132 .

I keep the data from nus_data in the uint8_t array. Then I am trying to write the array with use fds_write.

My fds_write function;

static ret_code_t kls_fds_write(uint32_t file_id, uint32_t record_key , uint8_t write_data[])
{		
	fds_record_t        record;
	fds_record_desc_t   record_desc;
	
	// Set up record.
	record.file_id           = file_id;
	record.key               = record_key;
	record.data.p_data       = &write_data;
	record.data.length_words = (sizeof(write_data) + 3) / 4;     //sizeof(write_data);   //(sizeof(write_data) + 3) / sizeof(uint32_t);
	
	ret_code_t rc;
	rc = fds_record_write(&record_desc, &record);
	if (rc != FDS_SUCCESS)
	{
			/* Handle error. */
			NRF_LOG_INFO("FDS Write Handle error.");
			return rc;
	}
	NRF_LOG_INFO("Writing Record ID = %d \r\n",record_desc.record_id);
	return NRF_SUCCESS;
	
}

I use my fds_write function by this way;

static void save_data( uint8_t *p_data)
{
	NRF_LOG_INFO("save_data");
	uint8_t source_data_0[10] ;		
	
	// assign source datas  ********************************	
	for (uint32_t i = 0; i < 10; i++)				
	{
		source_data_0[i] = p_data[i];
	}
	while (flag_write_fds == false);
	kls_fds_write(FILE_ID, RECORD_KEY, source_data_0);
	
	NRF_LOG_HEXDUMP_INFO(source_data_0, sizeof(source_data_0));
	
	allow_advertisement = false;

}

Then I am trying to read and store the data into another array.

My fds_read function;

static ret_code_t kls_fds_read(uint32_t file_id, uint32_t relevant_record_key , uint8_t read_data[])
{	
		fds_flash_record_t  flash_record;
		fds_record_desc_t   record_desc;
		fds_find_token_t    ftok;
		fds_record_t        record;
		/* It is required to zero the token before first use. */
		memset(&ftok, 0x00, sizeof(fds_find_token_t));
		
		uint32_t err_code;
		
		NRF_LOG_INFO("Start searching... \r\n");
		// Loop until all records with the given key and file ID have been found.
		while (fds_record_find(file_id, relevant_record_key, &record_desc, &ftok) == FDS_SUCCESS)
		{
				err_code = fds_record_open(&record_desc, &flash_record);
				if ( err_code != FDS_SUCCESS)
				{
					return err_code;		
				}
				
				NRF_LOG_INFO("Found Record ID = %d\r\n",record_desc.record_id);
				
				uint8_t * pointer_to_record_data;
				pointer_to_record_data = (uint8_t *)record.data.p_data; 
				
				if(flash_record.p_header->record_key == relevant_record_key)
				{
					for(uint8_t i = 0; i < 10; i++)
					{
							read_data[i] = *pointer_to_record_data;
							pointer_to_record_data++;
					}
				}
				
				NRF_LOG_INFO("Data = ");
				NRF_LOG_HEXDUMP_INFO(read_data, sizeof(read_data));
				NRF_LOG_INFO("\r\n");

				// Access the record through the flash_record structure.
				// Close the record when done.
				err_code = fds_record_close(&record_desc);
				if (err_code != FDS_SUCCESS)
				{
					return err_code;	
				}
		}
		return NRF_SUCCESS;		
}

I use my fds_read function by this way;

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);
    	
    NRF_LOG_INFO("dest_data_0 : ");
    NRF_LOG_HEXDUMP_INFO(dest_data_0, 10);
    
}

I can write and read something but these are not meaningful data. Or I can not read the data I wrote because of anything. I obviously could not figure out exactly where the problem was.

The steps I want to take are as follows;

• Store particular nus_data into an array (uint8_t source_data_0[10] ) -> I'm already doing this. No problem.
• Write the stored array(uint8_t source_data_0[10] ) via FDS -> I do that already, but I do not know exactly whether it is successful.
• Read the stored array(uint8_t source_data_0[10] )via FDS and Store the read array(source_data_0[10] ) in another array (uint8_t dest_data_0[10]  = {0}).

Test Result;

I sent the nus data( "aaaaaaaaaa" ) and I can store it into source_data_0[] successfully. Then I use my fds_write function;

0> <info> app: save_data
0> <info> app: Writing Record ID = 1
0>
0> <info> app: 61 61 61 61 61 61 61 61|aaaaaaaa
0> <info> app: 61 61 |aa

Finally I tried to read and result is;

0> <info> app: first_Setup Start

0> <info> app: Start searching...
0>
0> <info> app: Found Record ID = 1
0>
0> <info> app: Data =
0> <info> app: 00 04 00 20 |...
0> <info> app:
0>
0> <info> app: dest_data_0 :
0> <info> app: 00 04 00 20 E9 08 00 00|... é...
0> <info> app: 7D 05 |}.

As a result; The data I read is not the same as the data I write . May be I read it in the wrong format, I do not know exactly. 

So, Do you have any suggestion ?

[haakonsh]

Hey Ugur,

I believe I found a bug:

fds_record_t record; // Uninitialized variable

uint8_t * pointer_to_record_data;
pointer_to_record_data = (uint8_t *)record.data.p_data; // points to an address with unknown data

if(flash_record.p_header->record_key == relevant_record_key)
{
	for(uint8_t i = 0; i < 10; i++)
	{
		read_data[i] = *pointer_to_record_data; // record has not been used
		pointer_to_record_data++;
	}
}

You never used the variable 'record' and since it is uninitialized it's content is in an unknown state. The compiler has probably reused the memory of other parts of the program that is no longer in the scope and you will therefore read garbage data.

Cheers,

Håkon.

[haakonsh]

Hey Ugur,

I spoke in error earlier when I said that the record descriptor was not used. It is clearly used in:
while (fds_record_find(file_id, relevant_record_key, &record_desc, &ftok) == FDS_SUCCESS)

I believe it's the way you are accessing the fds_flash_record_t flash_record afterwords.

uint32_t your_data[8] = {0};
uint8_t your_byte = 0;

for(uint8_t i = 0; i < flash_record->p_header.length_words; i++){
    your_data[i] = flash_record->p_data[0];
}

your_byte = (uint8_t)your_data[0];

[purgoufr]

I tried the memcpy function ;

static ret_code_t kls_fds_read(uint32_t file_id, uint32_t relevant_record_key , uint8_t read_data[])
{	
	fds_flash_record_t  flash_record;
	fds_record_desc_t   record_desc;
	fds_find_token_t    ftok;
	/* It is required to zero the token before first use. */
	memset(&ftok, 0x00, sizeof(fds_find_token_t));
		
	uint32_t err_code;
		
	NRF_LOG_INFO("Start searching... \r\n");
	// Loop until all records with the given key and file ID have been found.
	while (fds_record_find(file_id, relevant_record_key, &record_desc, &ftok) == FDS_SUCCESS)
	{
		err_code = fds_record_open(&record_desc, &flash_record);
		if ( err_code != FDS_SUCCESS)
		{
			return err_code;		
		}
				
		NRF_LOG_INFO("Found Record ID = %d\r\n",record_desc.record_id);

		memcpy(read_data, flash_record.p_data, flash_record.p_header->length_words * sizeof(uint32_t));
				
		NRF_LOG_INFO("Data: %u, Length: %u", read_data, flash_record.p_header->length_words * sizeof(uint32_t));
				
		// Access the record through the flash_record structure.
		// Close the record when done.
		err_code = fds_record_close(&record_desc);
		if (err_code != FDS_SUCCESS)
		{
			return err_code;	
		}
	}
		return NRF_SUCCESS;		
}

I sent nus_data"A01100040" to write in fds

0> <info> app: 41 30 31 31 30 30 30 34|A0110004
0> <info> app: 30 00 |0. 

Result;

0> <info> app: Found Record ID = 1
0>
0> <info> app: Data: 536895120, Length: 4

Unfortunately, I still could not write the data I wanted, and then I could not get the data itself (in uint8_t format). 

[purgoufr]

Hi Haakonsh,

The write function does not work when there are 8 or more bytes. For example I modified like this;

static uint8_t m_deadbeef[8] = {0x01,0x02,0x03,0x04,0x05,0x06,0x07,0x08}; and it worked.

static ret_code_t kls_fds_write(uint32_t write_file_id, uint32_t write_record_key , uint8_t write_data[])
{		
	//static uint32_t const m_deadbeef[2] = {0xDEADBEEF,0xBAADF00D};
		static uint8_t m_deadbeef[8] = {0x01,0x02,0x03,0x04,0x05,0x06,0x07,0x08};
		fds_record_t        record;
		fds_record_desc_t   record_desc;
	
		// Set up record.
		record.file_id              = write_file_id;
		record.key              		= write_record_key;
		record.data.p_data       		= &m_deadbeef;
		record.data.length_words   	= sizeof(m_deadbeef)/sizeof(uint8_t);
				
		ret_code_t ret = fds_record_write(&record_desc, &record);
		if (ret != FDS_SUCCESS)
		{
				return ret;
		}
		 NRF_LOG_INFO("Writing Record ID = %d \r\n",record_desc.record_id);
		return NRF_SUCCESS;
	
}

static ret_code_t kls_fds_read(uint32_t read_file_id, uint32_t relevant_record_key , uint8_t read_data[])
{	
		fds_flash_record_t  flash_record;
		fds_record_desc_t   record_desc;
		fds_find_token_t    ftok ={0};//Important, make sure you zero init the ftok token
		uint8_t *data;
		uint32_t err_code;
		
		NRF_LOG_INFO("Start searching... \r\n");
		// Loop until all records with the given key and file ID have been found.
		while (fds_record_find(read_file_id, relevant_record_key, &record_desc, &ftok) == FDS_SUCCESS)
		{
				err_code = fds_record_open(&record_desc, &flash_record);
				if ( err_code != FDS_SUCCESS)
				{
					return err_code;		
				}
				
				NRF_LOG_INFO("Found Record ID = %d\r\n",record_desc.record_id);

				data = (uint8_t *) flash_record.p_data;
				for (uint8_t i=0;i<flash_record.p_header->length_words;i++)
				{
					read_data[i] = data[i];
				}

				
				NRF_LOG_HEXDUMP_INFO(read_data, sizeof(read_data));
				// Access the record through the flash_record structure.
				// Close the record when done.
				err_code = fds_record_close(&record_desc);
				if (err_code != FDS_SUCCESS)
				{
					return err_code;	
				}
		}
		return NRF_SUCCESS;	
}

But I tried this;

static uint8_t m_deadbeef[10] = {0x41,0x30,0x31,0x31,0x30,0x30,0x30,0x34,0x30,0x24}; and it did not work. 

It does not work if it is bigger than eight. 

Do you have any suggestion for that?

[purgoufr]

Hi Haakonsh,

Thank you very much for your interest. I reach the solution through another question. But I learned a lot from your answers. So I wanted to share the situation with you. 

Solution Link

[haakonsh]

Hey purgoufr,

This is strange. Maybe a compiler optimization issue or something. Have you tried declaring the m_deadbeef array as a 'const'?

Anyway I'm glad that you got to move on with your development. I hate it when I get stuck on issues like these.

Cheers,

Håkon.

[purgoufr]

The const is not suitable for me because I saved the data from nus_data. So I do not record constant data. That's why, when I compile, I get an error. Anyway, thanks for everything.