public static byte[] ReadEV3File(String fullname)
{
try
{
lock (sync)
{
// if not already done, memorize the start time and fire up the communication
MemorizeStartTime();
EstablishConnection();
// prepare the pinger packet to keep the remote-controll target alive during large file transfer
ByteCodeBuffer c = new ByteCodeBuffer();
c.OP(0x3A); // Move32_32
c.CONST(42); // move this value
c.GLOBVAR(0); // to global variable 0-3
c.OP(0x7E); // Memory_Write
c.CONST(1); // program slot 1 = user slot
c.CONST(0); // write to global variables
c.CONST(0); // to global variable 0
c.CONST(4); // write 4 bytes
c.GLOBVAR(0); // take the prepared value 42
// finally execute the command
return(con.ReadEV3File(fullname, c));
}
}
catch (Exception)
{ // no connection or other severe error - must terminate immediately
System.Environment.Exit(1);
}
return(null);
}
// 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();
}
}
// Periodically modify a flag in the global variables of program slot 1.
// The program in slot 1 is a watchdog program that will notice when this "pings" no longer
// arrive and will stop itself and shut down motors and sensors gracefully.
// On the other side, the pinger will monitor if the watchdog is still running (could have
// been stopped manually by the user) and if so, terminates the Basic program also.
private static void runpings()
{
ByteCodeBuffer c = new ByteCodeBuffer();
c.OP(0x3A); // Move32_32
c.CONST(42); // move this value
c.GLOBVAR(0); // to gloval variable 0-3
c.OP(0x7E); // Memory_Write
c.CONST(1); // program slot 1 = user slot
c.CONST(0); // write to global variables
c.CONST(0); // to global variable 0
c.CONST(4); // write 4 bytes
c.GLOBVAR(0); // take the prepared value 42
c.OP(0x0C); // opProgram_Info
c.CONST(0x16); // CMD: GET_STATUS = 0x16
c.CONST(1); // program slot 1 = user slot
c.GLOBVAR(0);
for (; ;)
{
lock (sync)
{
byte[] packet = null;
try
{
packet = con.DirectCommand(c, 4, 0);
}
catch (Exception e)
{
throw e;
}
// detected communication error or watchdog progam is no longer running
if (packet == null || packet.Length <= 0 || packet[0] == 0x40)
{
System.Environment.Exit(1);
}
}
System.Threading.Thread.Sleep(500);
}
}
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;
}
}
