How to detect joypad

public OnPlayerUpdate(playerid) {
    new keys, ud, lr;
    GetPlayerKeys(playerid, keys, ud, lr);
    if((ud != 128 && ud != 0 && ud != -128) || (lr != 128 && lr != 0 && lr != -128))
        // using a joypad
    else
        // not using a joypad

    return 1;
}