Hi Gents,
I am using Cerbuino Bee, and VS2010 and 4.2 QFE2 Firmware…
My code basically is trying to read from 3 inputs: SPI, UART and Analog, and then it writes the data in SD card…
but sometimes I have this exception:
A first chance exception of type ‘System.InvalidOperationException’ occurred in Microsoft.SPOT.Hardware.dll
Sometimes the program is terminated, and sometimes it proceeds
Do you have any idea why I have this?
Regards 
May be a sample code to reproduce your experiment will be a good starting point.
Thanks guys, and here is my code:
BTW: the full exception was:
[em]A first chance exception of type ‘System.InvalidOperationException’ occurred in Microsoft.SPOT.Hardware.dll
Exception performing Timer operation[/em]
using System;
using System.Collections;
using System.Threading;
using Microsoft.SPOT;
using Microsoft.SPOT.Presentation;
using Microsoft.SPOT.Presentation.Controls;
using Microsoft.SPOT.Presentation.Media;
using Microsoft.SPOT.Touch;
using Gadgeteer.Networking;
using GT = Gadgeteer;
using GTM = Gadgeteer.Modules;
using GTI = Gadgeteer.Interfaces;
using Gadgeteer.Modules.GHIElectronics;
using System.IO;
using Microsoft.SPOT.IO;
namespace Final
{
public partial class Program
{
//GPS
private GT.Timer _timer;
private string _root;
//SPI
static GT.Socket _socket;
static GTI.SPI.Configuration _config;
static GTI.SPI _spi;
// This method is run when the mainboard is powered up or reset.
public void ProgramStarted()
{
// Serial Config.
usbSerial.Configure(9600,
GT.Interfaces.Serial.SerialParity.None,
GT.Interfaces.Serial.SerialStopBits.One, 8);
usbSerial.SerialLine.Open();
usbSerial.SerialLine.DataReceived += new
GT.Interfaces.Serial.DataReceivedEventHandler(SerialLine_DataReceived);
// SPI Config
_socket = GT.Socket.GetSocket(1, true, null, null);
_config = new GTI.SPI.Configuration(false, 0, 0, false, true, 2000);
_spi = new GTI.SPI(_socket, _config, GTI.SPI.Sharing.Exclusive, _socket, GT.Socket.Pin.Five, null);
// SD Card Config.
GHI.OSHW.Hardware.StorageDev.MountSD();
if (VolumeInfo.GetVolumes()[0].IsFormatted)
{
_root = VolumeInfo.GetVolumes()[0].RootDirectory;
_timer = new GT.Timer(1000);
_timer.Tick += new GT.Timer.TickEventHandler(TimerTick);
_timer.Start();
}
}
void TimerTick(GT.Timer timer)
{
// *******************************
string fileName = Path.Combine(_root, "FinalDONE.txt");
Stream stream;
// GPS Reading
int NumberOfBytesToRead = usbSerial.SerialLine.BytesToRead;
byte[] SerialBuffer = new byte[NumberOfBytesToRead];
usbSerial.SerialLine.Read(SerialBuffer, 0, NumberOfBytesToRead);
// SPI Reading
byte[] BytesWrite = new byte[] { 0, 1, 2, 3, 4 };
byte[] SPIBuffer = new byte[5];
_spi.WriteRead(BytesWrite, SPIBuffer);
// Pressure Config. & Reading
var analogInput = new Microsoft.SPOT.Hardware.AnalogInput(GHI.OSHW.Hardware.FEZCerbuino.Pin.AnalogIn.A1);
var analogValue = analogInput.Read();
// SD Logging
if (File.Exists(fileName))
{
stream = File.OpenWrite(fileName);
stream.Position = stream.Length; //FM Not To Overwrite
}
else
{
stream = File.Create(fileName);
}
using (var writer = new StreamWriter(stream))
{
// GPS writing to SD
writer.Write("GPS Message: ");
for (int g = 0; g < NumberOfBytesToRead; g++)
{
char GPSchar = (char)SerialBuffer[g];
Debug.Print(GPSchar.ToString());
Debug.Print("#");
writer.Write(GPSchar.ToString());
}
writer.WriteLine("");
writer.WriteLine("");
// SPI writing to SD
writer.Write("IMU Message: ");
for (int s = 0; s < 5; s++)
{
char SPIchar = (char)SPIBuffer[s];
Debug.Print(SPIchar.ToString());
Debug.Print("#");
writer.Write(SPIchar.ToString());
}
writer.WriteLine("");
writer.WriteLine("");
// Pressure writing to SD
writer.WriteLine("Analog Value: " + analogValue);
writer.WriteLine("");
writer.WriteLine("");
Debug.Print(analogValue.ToString());
}
stream.Dispose();
}
void SerialLine_DataReceived(GT.Interfaces.Serial sender, System.IO.Ports.SerialData data)
{
}
}
}
It seems the Exception was when it reach this for the second time:
var analogInput = new Microsoft.SPOT.Hardware.AnalogInput(GHI.OSHW.Hardware.FEZCerbuino.Pin.AnalogIn.A0);
Dear PetaByte,
Could this be occuring as the timer is trying to repeatedly re-declare the Cerbuino Analogue Pin? Perhaps finding a way to take this part of the code outside of the timer (Event Handler?) may avoid the Exception.
@ IanW - Good catch!
I would move allocation of the fixed size buffers outside of the tick handler as well.
Thnx Gents,
That what I thought and what I tried actually, but it seems that (analogInput ) has to be defined “inside” the timer, otherwise there will be an error and it will be as if it is not declared!!
However, I’ll keep trying …
Regards…
What kind of error?
I would try with
analogInput.Dispose()
after analog reading is done. It I also think it is much better to define analogInput as global variable.
Hello Guys
@ Architect:
When I defined:
var analogInput = new Microsoft.SPOT.Hardware.AnalogInput(GHI.OSHW.Hardware.FEZCerbuino.Pin.AnalogIn.A0);
as a global variable I got this error:
[em]Error 1 The type or namespace name ‘var’ could not be found (are you missing a using directive or an assembly reference?)[/em]
@ jernejk:
Thaaaaaanx dude
You were alright, “analogInput.Dispose()” killed the exception
Thanx for all of you gents…
But I still recommend you to define global variable, but you can’t use var. Just change var with the correct type like this:
Microsoft.SPOT.Hardware.AnalogInput analogInput = new Microsoft.SPOT.Hardware.AnalogInput(GHI.OSHW.Hardware.FEZCerbuino.Pin.AnalogIn.A0);