在Windows 10 IOT上运行后台UWP时出现COMException

Question

I am developing an I2C solution for a Raspberry Pi and Teensy 3.6 Arduino . The Pi is going to send NTP via I2C to the Arduino. I have done research for weeks, and tried to test the code below, and receive a couple errors.

public sealed class StartupTask : IBackgroundTask
{
    public async void Run(IBackgroundTaskInstance taskInstance)
    {
        while(true)
        {
            Wait(5000);
            try
            {
                await I2C();
            }
            catch (Exception ex)
            {
                // eats fast inputs
            }
        }
    }

    private async void Wait(int millis)
    {
        await Task.Delay(millis);
    }

    private async Task I2C()
    {
        var settings = new I2cConnectionSettings(1);
        settings.BusSpeed = I2cBusSpeed.FastMode;
        var controller = await I2cController.GetDefaultAsync();

        using (I2cDevice device = controller.GetDevice(settings))
        {
            byte[] writeBuf = { 0x01, 0x02, 0x03, 0x04 };
            device.Write(writeBuf);
        }
    }
}

Using the debug console, I have found that the I2C method never goes all the way through the using statement.

EXCEPTIONS:

Exception thrown: 'System.Runtime.InteropServices.COMException' in i2cTestIOT.winmd WinRT information: Unexpected number of bytes was transferred. Expected: '. Actual: '. Exception thrown: 'System.Runtime.InteropServices.COMException' in System.Private.CoreLib.ni.dll WinRT information: Unexpected number of bytes was transferred. Expected: '. Actual: '.

Answer 1

I can't reproduce this error with Raspberry pi and Arduino Uno using exact your code.(If it is a complete reproducible code). So

Using the debug console, I have found that the I2C method never goes all the way through the using statement.

Make sure the 1 is the right I2C address for your Teensy 3.6 Arduino and check the SDA and SCL connect correctly. Refer to Windows IoT Core pin mappings .

Add deferral = taskInstance.GetDeferral(); if you want the background application always running. Otherwise when the Run method ends, the background application ends.

private BackgroundTaskDeferral deferral;
public void Run(IBackgroundTaskInstance taskInstance)
{
    deferral = taskInstance.GetDeferral();

    //
    // TODO: Insert code to start one or more asynchronous methods
    //
}

Try the StandardMode speed first then FastMode later.