btleServiceDataGet (Function)

This function retrieves the service data from a remote device.

The service data is custom data that is part of the 32 bytes in the advertising data.

A device may be sending multiple types of service data, so it may be necessary to call this function multiple times with increasing index until it returns BT_ERR_NODATA.

Note: To be able to receive advertising data, the adapter must be scanning, using btScanStart.

Input:

dev : STRING

The address of the device to get the data from.

index : INT (default 0)

The index of the service data to read.

size : INT

The size of the buffer.

data : PTR

The buffer to store the data in. Must be at least 31 bytes long to be able to store all normal data.

Output:

size : INT

The number of valid bytes in the buffer. If the buffer is too small, this will contain the needed size.

UUID : STRING

The UUID of the service data.

Returns: INT

Declaration:

FUNCTION btleServiceDataGet : INT;
VAR_INPUT
  dev      : STRING;

  index    : INT := 0;

  size     : ACCESS INT;

  data     : MANDATORY PTR;

  UUID     : ACCESS STRING;
END_VAR;

Example:

INCLUDE rtcu.inc
 
PROGRAM test;
VAR
  rc      : INT;
  sz      : INT;
  address : STRING;
  uuid    : STRING;
  data    : ARRAY [1..32] OF SINT;
END_VAR;
 
// Turn on the Bluetooth library
btPower();
 
// Start scanning for BLE devices to receive advertising data.
btScanStart(transport:=2);
 
BEGIN
  ...
  // retrieve service data from the device
  sz := SIZEOF(data);
  rc := btleServiceDataGet(dev:=address, data:=ADDR(data), size := sz, UUID := uuid);
  DebugFmt(message:="btleServiceDataGet: \1, sz \2$N", v1:=rc, v2 := sz);
 ...
END;
 
END_PROGRAM;