How to store Float array in nRF51 using FDS

RE: How to store Float array in nRF51 using FDS

Ole Bauck — Mon, 24 Oct 2016 11:23:30 GMT

Each int16_t will take two bytes, but as you specify the length in words (record_chunk.length_words) you will have to round up to the closest word length. One word is 4 bytes.

So if you have an array of 3 int16_t values (int16_t data[3]) the length have to be 2, so it will occupy 8 bytes, even though the array itself is only 6 bytes. The 2 bytes that are not used will be garbage.

If you have an array of 4 int16_t values (int16_t data[4]) the length also have to be 2 and it will occupy 8 bytes.

In addition for every record you will have a 12 bytes header, see here.

RE: How to store Float array in nRF51 using FDS

saiteja — Thu, 20 Oct 2016 10:29:47 GMT

hi, how much size it will take if i write int16_t value in to the flash using FDS.

RE: How to store Float array in nRF51 using FDS

saiteja — Thu, 20 Oct 2016 10:29:32 GMT

hi, how much size it will take if i write int16_t value in to the flash using FDS.

RE: How to store Float array in nRF51 using FDS

RK — Mon, 03 Oct 2016 12:32:32 GMT

Indeed - that's what I was trying to tell him all along, that his version of printf probably didn't do anything with floats and why I suggested casting to ints to print, because that always works and would have proved it was just the output was an issue.

Never mind.

RE: How to store Float array in nRF51 using FDS

Wojtek — Mon, 03 Oct 2016 12:28:27 GMT

So, RK's idea was actually correct - it was problem with compiled version of printf, that has to bo float-enabled.

RE: How to store Float array in nRF51 using FDS

saiteja — Mon, 03 Oct 2016 12:21:28 GMT

Found the solution. The problem is here i am able to write the float array[20][3]; and also able to read. but while printing Termite is not printing Float values through UART.

by placing

LDFLAGS += --specs=nano.specs -lc -lnosys -u _printf_float

in the Make file i am able to print float array.

Anyway thanks RK, Ole Bauck for helping me

RE: How to store Float array in nRF51 using FDS

RK — Fri, 30 Sep 2016 12:54:12 GMT

Have you tried what I suggested yet? Changing

NRF_LOG_PRINTF("%f ",data[i]);

NRF_LOG_PRINTF("%d ",(int(data[i]*1000));

or even ... use an actual debugger and go look at the values instead of logging them. There's a reason debuggers were invented.

RE: How to store Float array in nRF51 using FDS

saiteja — Fri, 30 Sep 2016 12:51:53 GMT

i even unable to store and read this value

static float const m_deadbeef[1] = {1.23};

RE: How to store Float array in nRF51 using FDS

RK — Fri, 30 Sep 2016 11:37:23 GMT

I didn't suggest not STORING floats, I suggested convering them to integers to print them in your test because there are some instances of printf() which do not deal with floats.

RE: How to store Float array in nRF51 using FDS

saiteja — Fri, 30 Sep 2016 11:35:33 GMT

@RK :- It will definitely work but my requirement is i need to store only floats.

and also there is so many values like this 0.0234, 0.2,35.002, -0.005. it is not possible to multiply with 1000.

RE: How to store Float array in nRF51 using FDS

RK — Fri, 30 Sep 2016 11:24:29 GMT

Does your printf() actually print floats properly? Some don't. Try multiplying by 1000, casting to an integer and printing with %d to see if you get anything different.

RE: How to store Float array in nRF51 using FDS

saiteja — Fri, 30 Sep 2016 11:19:28 GMT

here is my main.c

drive.google.com/open

RE: How to store Float array in nRF51 using FDS

saiteja — Fri, 30 Sep 2016 11:13:50 GMT

@Ole Bauck :- i commented my m_deadbeef float array above. can u try with that.

RE: How to store Float array in nRF51 using FDS

saiteja — Fri, 30 Sep 2016 11:10:29 GMT

@Alex:- same issue i am facing even i replace record_chunk.length_words = sizeof(m_deadbeef)/sizeof(uint32_t);

RE: How to store Float array in nRF51 using FDS

Ole Bauck — Fri, 30 Sep 2016 11:10:26 GMT

I can't figure out what is wrong. I test with the same code and it is working fine. Can you just try to print out the content of m_deadbeef to see if that works?

RE: How to store Float array in nRF51 using FDS

saiteja — Fri, 30 Sep 2016 11:08:45 GMT

let me try

RE: How to store Float array in nRF51 using FDS

Alex — Fri, 30 Sep 2016 11:07:10 GMT

Are you sure m_deadbeef[0][0] has size of word? I would try something like record_chunk.length_words = sizeof(m_deadbeef)/sizeof(uint32_t);

RE: How to store Float array in nRF51 using FDS

saiteja — Fri, 30 Sep 2016 11:00:00 GMT

if i write integer array m_deadBeef[20][3]

it is working fine and also i am able to read it back....

RE: How to store Float array in nRF51 using FDS

saiteja — Fri, 30 Sep 2016 10:58:07 GMT

here the info the terminal is giving.

Writing Record ID = 1

Start searching...

Found Record ID = 1

Data =

may be these are emty space char's

RE: How to store Float array in nRF51 using FDS

saiteja — Fri, 30 Sep 2016 10:51:56 GMT

yes i defined it globally

RE: How to store Float array in nRF51 using FDS

Ole Bauck — Fri, 30 Sep 2016 10:49:50 GMT

What is the output you are seeing in the terminal?

RE: How to store Float array in nRF51 using FDS

Ole Bauck — Fri, 30 Sep 2016 10:48:44 GMT

This should work, I don't see what is wrong. m_deadbeef is defined globally (outside the fds_test_write function)?

RE: How to store Float array in nRF51 using FDS

saiteja — Fri, 30 Sep 2016 10:43:10 GMT

here is my float data:------

float m_deadbeef[20][3] = {

		{2.002139,      4.295340,       12.436197,      },

		{2.575441,      4.983300,       12.436197,      },

		{2.804763,      4.753978,       12.206882,      },

		{2.690099,      4.524662,       12.436197,      },

		{3.034079,      4.295340,       11.748239,      },

		{3.263401,      4.066018,       11.977560,      },

		{3.148742,      4.066018,       12.550861,      },

		{2.919421,      3.836702,       13.009499,      },

		{2.804763,      3.722038,       13.124157,      },

		{2.919421,      3.492722,       13.009499,      },

		{3.263401,      3.722038,       12.665519,      },

		{3.492722,      4.409998,       13.582801,      },

		{1.887481,      3.951360,       13.124157,      },

		{2.346119,      4.409998,       12.206882,      },

		{1.658159,      4.180682,       12.436197,      },

		{1.887481,      4.180682,       12.780177,      },

		{2.690099,      3.951360,       12.550861,      },

		{3.263401,      3.722038,       12.321539,      },

		{3.836702,      3.722038,       12.206882,      },

		{3.148742,      3.263401,       12.665519,      },
};

RE: How to store Float array in nRF51 using FDS

saiteja — Fri, 30 Sep 2016 10:40:39 GMT

hi can u check my write function

RE: How to store Float array in nRF51 using FDS

Ole Bauck — Fri, 30 Sep 2016 10:33:12 GMT

It should work with floats as well, could you post the write function in your question also?