ble data transfer

[Siva]

Hi,

I am using the following statements for send a string data over BLE.

static uint8_t Name3[BLE_NUS_MAX_DATA_LEN]= "xxxxxxxx";
	err_code = ble_nus_string_send(&m_nus, Name3, 20);	
	if (err_code != NRF_ERROR_INVALID_STATE)
	{
		APP_ERROR_CHECK(err_code);
	}	

But I am unable to send integers and floating values. Is there a function where I can send non-string data variables via BLE.

Regards Siva

[RichieJH]

So assume you want to send a uint16_t value of say 10000. This is of course two bytes and you must assign each byte of value to each element of the array Name3. One fairly easy way to do this is bit masking and shifting. So do this:

Name3[0] = (value & 0xFF00) >> 8;
Name3[1] = (value & 0x00FF);

Now say value was a unit32_t, which is 4 bytes long, then do this

Name3[0] = (value & 0xFF000000) >> 24;
Name3[1] = (value & 0x00FF0000) >> 16;
Name3[2] = (value & 0x0000FF00) >> 8;
Name3[3] = (value & 0x000000FF);

[awneil]

That won't work - you can't just do

 Name3[1] = uint32_t some_int; 
 Name3[5] = uint16_t something_else; 

You have to copy each byte individually

[RichieJH]

You do not have to copy each byte individually and this does work.

unint32_t some_int = 100; Name3[0] = some_int;

The next 4 bytes in the array will be taken up with some_int with the value of 100. Not the most efficient way to store the value of 100, but the principle works. Remember Name3 is a Uint8_t array.

[awneil]

No! that is not the way 'C' works!!

When you assign to Name3[x] you are just assigning to that one element - using the standard 'C' conversion rules if the RHS of the assignment is not the same type as the LHS.

It does not run-on to subsequent elements in the array!!

[RichieJH]

Of course it does, have you actually tried it? I have and it works. So unless my compiler and SDK has magical powers I'm not sure why you are insisting it doesn't.

[RichieJH]

Actually, you might be right. I've just noticed my values never been larger than one byte so while it compiles fine and appears to work, what is happening is the value is being assigned to that array element and when putting in a value greater than one byte it is being lost.