mono - C# Serial Port BNO055 Sensor Communication -

i trying use c# , mono talk imu sensor (bno055) on raspberry pi. no matter do, cannot read , write sensor. can more experience let me know proper way is? thanks.

initialization:

    private void connecttobno055()     {         gpio.write(resetpin, true);         task.delay(650).wait();          port                = new serialport();         port.portname       = portname;         port.baudrate       = 115200;         port.parity         = parity.none;         port.databits       = 8;         port.stopbits       = stopbits.one;         port.handshake      = handshake.none;         port.readtimeout    = 5000;         port.writetimeout   = 5000;          try         {             port.open();              while (!port.isopen) { task.delay(1).wait(); }              setmode(operationmode.operation_mode_config);              writeregister((byte)pageidregisterdefinition.bno055_page_id_addr, 0, false);              byte chipid = readregister((byte)pageregisterdefinitionstart.bno055_chip_id_addr);              if ((byte)i2caddress.bno055_id == chipid)             {                 reset();                  writeregister((byte)moderegisters.bno055_pwr_mode_addr, (byte)powermode.power_mode_normal);                   writeregister((byte)moderegisters.bno055_sys_trigger_addr, 0x0);                   setmode(operationmode.operation_mode_ndof);                  connected = true;                 console.writeline("connected imu.");                  console.writeline("calibrating imu. . .");                  bno055.calibrationstatus lastcal;                 bno055.calibrationstatus cal = getcalibrationstatus();                  console.writeline("system: " + cal.system.tostring() + ", magnometer: " + cal.mag.tostring() + ", gyroscope: " + cal.gyro.tostring() + ", accelerometer: " + cal.accel.tostring());                 while (cal.system != 3 || cal.mag != 3 || cal.gyro != 3 || cal.accel != 3)                 {                     task.delay(250).wait();                      lastcal = cal;                     cal = getcalibrationstatus();                      if (cal.accel != lastcal.accel || cal.gyro != lastcal.gyro || cal.mag != lastcal.mag || cal.system != lastcal.system)                     {                         console.writeline("system: " + cal.system.tostring() + ", magnometer: " + cal.mag.tostring() + ", gyroscope: " + cal.gyro.tostring() + ", accelerometer: " + cal.accel.tostring());                     }                 }                  calibrated = true;                 console.writeline("imu calibrated.");             }             else             {                 console.writeline("unable connect imu.");             }         }         catch (exception)         {             console.writeline("unable connect imu.");         }     } 

io methods:

    private void writeregister(byte address, byte data, bool ack = true)     {         byte[] writebuffer = new byte[] { 0xaa, 0x00, address, 1, data };         byte[] response;         try         {             response = writedata(writebuffer, ack);             if (ack)             {                 if (0xee01 != (response[0] << 8 | response[1]))                     throw new exception(string.format("writeregister returned 0x{0:x2},0x{1:x2}", response[0], response[1]));             }         }         catch (exception ex)         {             console.writeline(string.format("writeregister error: {0}", ex.message));         }     }      private byte readregister(byte register)     {         byte[] commandbuffer = new byte[] { 0xaa, 0x01, register, 1 };         byte[] readbuffer = new byte[1];         try         {             readbuffer = readdata(commandbuffer, 1);         }         catch (exception ex)         {             console.writeline(string.format("readregister error: {0}", ex.message));         }         return readbuffer[0];     }      private byte[] writedata(byte[] command, bool ack = true, int retries = 5)     {         byte[] ackbuffer = new byte[2];         bool done = false;          while ((!done) && (retries-- > 0))         {             port.write(command, 0, command.length);              if (ack)             {                 while (port.bytestoread != 2) { task.delay(1).wait(); }                 port.read(ackbuffer, 0, 2);                  done = 0xee07 != (ackbuffer[0] << 8 | ackbuffer[1]);             }             else                 done = true;         }          if (!done)             throw new exception("writedata retries exceeded");         return ackbuffer;     }      private byte[] readdata(byte[] command, int readlength)     {         byte[] headerbuffer = new byte[2];         byte[] returnbuffer = new byte[readlength];          port.write(command, 0, command.length);          while (port.bytestoread != 2) { task.delay(1).wait(); }         port.read(headerbuffer, 0, 2);          if (headerbuffer[0] != 0xbb)             throw new exception(string.format("readdata error 0x{0:x2}{1:x2}", headerbuffer[0], headerbuffer[1]));         if (headerbuffer[1] != readlength)             throw new exception(string.format("readdata error: failed read {0} bytes.  read {1}", readlength, headerbuffer[1]));          while (port.bytestoread != readlength) { task.delay(1).wait(); }         port.read(returnbuffer, 0, readlength);          return returnbuffer;     } 

the issue here was trying read response sensor after writing data. solve problem, add loop waiting bytestoread property equal desired response length read.