// must be called while holding a lock on sync
private static void EstablishConnection()
{
// the first action also involves passing some SystemCommands and DirectCommands
if (con == null)
{
// try to start up connection (when failing, an exception is thrown)
con = ConnectionFinder.CreateConnection(false, true);
String filename = "/tmp/EV3-Basic Session.rbf";
// download the watchdog program as a file to the brick
con.CreateEV3File(filename, HexDumpToBytes(EV3Communication.Properties.Resources.WatchDog));
// before loading the watchdog program, check if there is no other program running
ByteCodeBuffer c = new ByteCodeBuffer();
c.OP(0x0C); // opProgram_Info
c.CONST(0x16); // CMD: GET_STATUS = 0x16
c.CONST(1); // program slot 1 = user slot
c.GLOBVAR(8);
// load and start it
c.OP(0xC0); // opFILE
c.CONST(0x08); // CMD: LOAD_IMAGE = 0x08
c.CONST(1); // slot 1 = user program slot
c.STRING(filename);
c.GLOBVAR(0);
c.GLOBVAR(4);
c.OP(0x03); // opPROGRAM_START
c.CONST(1); // slot 1 = user program slot
c.GLOBVAR(0);
c.GLOBVAR(4);
c.CONST(0);
// after starting, check if indeed running now
c.OP(0x0C); // opProgram_Info
c.CONST(0x16); // CMD: GET_STATUS = 0x16
c.CONST(1); // program slot 1 = user slot
c.GLOBVAR(9);
// as additional startup-action, reset the hardware (sensors and motors)
c.OP(0x99); // opInput_Device (CMD, …)
c.CONST(0x0A); // CLR_ALL = 0x0A
c.CONST(-1); // LAYER – Specify chain layer number [0-3] (-1 = All)
byte[] response = con.DirectCommand(c, 10, 0);
if (response == null || response[8] != 0x0040 || response[9] == 0x0040)
{
throw new Exception("Could not start EV3 remote client on device");
}
// set up local ping thread to periodically send a command to the watchdog
// program to keep it alive (and check if the brick is still operating)
(new System.Threading.Thread(runpings)).Start();
}
}
private static EV3Connection TestConnection(EV3Connection con)
{
try
{
// perform a tiny direct command to check if communication works
ByteCodeBuffer c = new ByteCodeBuffer();
c.OP(0x30); // Move8_8
c.CONST(74);
c.GLOBVAR(0);
byte[] response = con.DirectCommand(c, 1, 0);
if (response == null || response.Length != 1 || response[0] != 74)
{
throw new Exception("Test DirectCommand delivers wrong result");
}
return(con);
}
catch (Exception e)
{
con.Close();
throw e;
}
}
public static EV3Connection CreateConnection(bool isUIThread, bool automaticallyUseSingleUSB)
{
// return new EV3ConnectionWiFi("10.0.0.140");
// retry multiple times to open connection
for (; ;)
{
// check which EV3 devices are connected via USB
int[] usbdevices = EV3ConnectionUSB.FindEV3s();
// if there is exactly one, try to open it
if (automaticallyUseSingleUSB && usbdevices.Length == 1)
{
try
{
return(TestConnection(new EV3ConnectionUSB(usbdevices[0])));
}
catch (Exception)
{ }
}
// when not able to open the one single USB connection, try also the serial ports
String[] ports = System.IO.Ports.SerialPort.GetPortNames();
// in this case also check if there are some IP addresses configured as possible connection targets
IPAddress[] addresses = LoadPossibleIPAddresses();
// because of a strange bug in .net 3.5, sometimes the port name gets an extra letter of unpredicable content - try to fix it in some cases
for (int i = 0; i < ports.Length; i++)
{
String n = ports[i];
if (n.StartsWith("COM"))
{
char last = n[n.Length - 1]; // trim away last letter if it is not a digit (but this does not always help)
if (last < '0' || last > '9')
{
ports[i] = n.Substring(0, n.Length - 1);
}
}
}
Array.Sort(ports, StringComparer.InvariantCulture);
// Create and show the window to select one of the connection possibilities
object port_or_device = DoModalConnectionTypeDialog(isUIThread, usbdevices, ports, addresses);
if (port_or_device == null)
{
throw new Exception("User canceled connection selection");
}
try
{
if (port_or_device is String)
{
EV3Connection c = TestConnection(new EV3ConnectionBluetooth((String)port_or_device));
SavePreferredConnection((String)port_or_device);
return(c);
}
else if (port_or_device is int)
{
EV3Connection c = TestConnection(new EV3ConnectionUSB((int)port_or_device));
SavePreferredConnection("USB " + port_or_device);
return(c);
}
else if (port_or_device is IPAddress)
{
IPAddress addr = (IPAddress)port_or_device;
EV3Connection c = TestConnection(new EV3ConnectionWiFi(addr));
if (!addresses.Contains(addr))
{
AddPossibleIPAddress(addr);
}
SavePreferredConnection(addr.ToString());
return(c);
}
}
catch (Exception)
{ } // if not possible, retry
}
}