btScanStart (Function)

This function makes the adapter start scanning for other devices.

It will find all the paired devices as well as the devices that match the provided parameters.

It is also used to receive BLE advertisement data.

Input:

transport : SINT (0..2) (default 0)

The type of device to search for:

 0        Any kind

 1        Classic Bluetooth.

 2        BLE.

UUID : STRING

Scan for a specific profile that has this UUID. Note that some devices may not have all profiles available to unpaired and unconnected devices.

The official UUIDs can be found in the Bluetooth specification (https://www.bluetooth.com/specifications/assigned-numbers/service-discovery).

RSSI : INT (default 0)

The required signal strength in dB.

pathloss: INT (default 0)

The device must advertise TX Power and have a computed pathloss less than this value.

timeout : DINT (default 0)

The timeout in seconds before stopping the scan automatically. If set to 0, it will keep scanning until btScanStop is called.

Returns: INT

Declaration:

FUNCTION btScanStart : INT;
VAR_INPUT
   transport   : SINT   := 0;
   UUID        : STRING := "";
   RSSI        : INT    := 0;
   pathloss    : INT    := 0;
   timeout     : DINT   := 0;
END_VAR;

Example:

 
INCLUDE rtcu.inc
 
PROGRAM test;
// These are the local variables of the program block
VAR
   rc      : INT;
   idx     : INT;
   address : STRING;
   devInfo : btDeviceInfo;
   i       : INT;
END_VAR;
 
   rc := btPower();
   DebugFmt(message:="btPower: \1 ", v1:=rc);
   
BEGIN
   // If not scanning; List the found devices and start a new scan
   IF btIsScanning() <> 1 THEN
      rc := _BT_OK;
      idx:=1;
      WHILE rc >= _BT_OK DO
         rc := btDeviceGet(idx:=idx, dev := address);
         IF rc >= _BT_OK THEN
            DebugFmt(message:="Address(\2): \1 , " + address, v1:=rc, v2:=idx);
 
            devInfo(dev := address);
            DebugFmt(message:="  " + devInfo.name+" , Class: \4, type: \3, connected: \1, tx power: \2", 
               v2:=devInfo.tx_power, v4:=devInfo.clss, v3:=devInfo.addr_type, v1:=SINT(devInfo.connected));
            DebugFmt(message:="  status: \1, paired: \2, trusted: \3", v1:=devInfo.status, 
               v2:=INT(devInfo.paired), v3:=INT(devInfo.trusted));
            DebugFmt(message:="  Profiles: \1", v1:=devInfo.profiles);
 
            FOR i:= 1 TO 16 DO
               IF devInfo.uuid[i] <> "" THEN
                  DebugFmt(message:="   [\1]: " + devInfo.uuid[i], v1:=i);
               END_IF;
            END_FOR;
         END_IF;
          
         idx := idx+1; 
      END_WHILE;
      DebugFmt(message:="btDeviceGet: \1 ", v1:=rc);
      
      rc := btScanStart(timeout := 5, transport := 1);
      DebugFmt(message:="btScanStart: \1 ", v1:=rc);
   ELSE
      Sleep(delay:=100);
   END_IF;
   
END;
 
END_PROGRAM;