btReceiveData (Functionblock)

The btReceiveData function block is used to receive data from a connected Bluetooth device. The btConnection function block must be assigned to the connection ID obtained from btConnect or btListen and a data buffer where the received data is placed. When the assigned connection ID receives data, the "Ready"-output will be set to TRUE, and the program may access the data in the assigned buffer.

It is important to update the btReceiveData function block often. This is because the Bluetooth module only has a limited buffer capacity, and if a large amount of data is received that is not taken out of the module with btReceiveData, the buffers will eventually be filled and data may be lost.

Input:

ID : SINT

The connection ID obtained with btConnect or btListen.

Data : PTR

Address of the buffer to receive the data in.

maxSize : INT

Maximum number of bytes to receive.

Output:

Ready : BOOL

TRUE when data is available. The output is valid until the next update of the function block.

Size : INT

Number of bytes received.

Declaration:

FUNCTION_BLOCK btReceiveData;
VAR_INPUT
  ID     : SINT;
  Data   : PTR;
  maxSize : INT;
END_VAR;
VAR_OUTPUT
  Ready   : BOOL;
  Size   : INT;
END_VAR;

Example:

INCLUDE rtcu.inc
 
PROGRAM test;
VAR
  rc           : INT;
  ConID_out   : SINT;
  ConID_in     : SINT;
  buffer       : ARRAY[1..127] OF SINT;
  RXbuffer_out : ARRAY[1..127] OF SINT;
  RXbuffer_in  : ARRAY[1..127] OF SINT;
  btRX_out     : btReceiveData;
  btRX_in      : btReceiveData;
  btCon_out   : btConnection;
  btCon_in   : btConnection;
END_VAR;
 
// Open the Bluetooth library
btOpen(name := "RTCU MX2");
 
// Set the Pin for incoming connections
btSetPin(pin := "1234");
 
// Initiate the outgoing connection
ConID_out:=btConnect(address:="00:e0:98:ae:17:23",pin:="0000");
DebugFmt(message:="Outgoing Connection ID =\1", v1:=ConID_out);
 
// Initiate the incoming connection
ConID_in:=btListen();
DebugFmt(message:="Incoming Connection ID =\1", v1:=ConID_in);
 
// setup the receive and connection function blocks
btRX_out.Data:=ADDR(RXbuffer_out);
btRX_out.MaxSize:=SIZEOF(RXbuffer_out);
btRX_out.id:=ConID_out;
btCon_out.id:=ConID_out;
 
// setup the receive and connection function blocks
btRX_in.Data:=ADDR(RXbuffer_in);
btRX_in.MaxSize:=SIZEOF(RXbuffer_in);
btRX_in.id:=ConID_in;
btCon_in.id:=ConID_in;
 
BEGIN
btCon_out();
btCon_in();
btRX_out();
btRX_in();
 
IF btCon_out.changed THEN
  DebugMsg(message:="Connection info changed:");
  DebugFmt(message:="    Connected=\1",v1:=INT(btCon_out.connected));
  DebugMsg(message:="    Address="+btCon_out.Address);
  DebugFmt(message:="    Error=\1", v1:=btCon_out.Errorcode);
END_IF;
 
IF btCon_in.changed THEN
  DebugMsg(message:="Connection info changed:");
  DebugFmt(message:="    Connected=\1",v1:=INT(btCon_in.connected));
  DebugMsg(message:="    Address="+btCon_in.Address);
  DebugFmt(message:="    Error=\1", v1:=btCon_in.Errorcode);
END_IF;
 
IF btRX_out.ready THEN
  DebugMsg(message:="Data Received from outgoing connection");
END_IF;
 
IF btRX_in.ready THEN
  DebugMsg(message:="Data Received from incoming connection");
END_IF;
 
  ...
 
END;
END_PROGRAM;