我如何使用c＃使树莓派中的GpioChangeReader与直接内存映射驱动程序一起使用

Question

我正在同时包含伺服电机和超声波传感器的项目中工作，但是当我在Direct Memory Mapped驱动程序中设置了树莓派时，伺服电机可以完美工作；可以，但是超声波检测无法用我想要的引脚将GpioChangeReader生成为新的。 .i尝试了所有可能的方式，但没有用...

using Microsoft.IoT.Lightning.Providers;
using System;
using System.Diagnostics;
using Windows.Devices;
using Windows.Devices.Gpio;
using Windows.Foundation;

namespace pi4
{
    public class UltrasonicSensor
    {
        private const int PIN_DRIVER = 27;
        private const int PIN_ECHO = 17;
        private GpioPin driverPin;
        private GpioPin echoPin;
        private GpioController gpioController;
       private GpioChangeReader changeReader;
        private double lastDelay = 0.0;
        private Stopwatch stopwatch;

        public UltrasonicSensor()
        {
            InitGpioAsync();
        }

        private async System.Threading.Tasks.Task InitGpioAsync()
        {

            if (LightningProvider.IsLightningEnabled)
            {
                LowLevelDevicesController.DefaultProvider = LightningProvider.GetAggregateProvider();
            }

         //   gpioController = await GpioController.GetDefaultAsync();
          gpioController = GpioController.GetDefault();

            if (gpioController == null)
            {
                return;
            }
            try
            {
                driverPin = gpioController.OpenPin(PIN_DRIVER,GpioSharingMode.Exclusive);
                echoPin = gpioController.OpenPin(PIN_ECHO, GpioSharingMode.Exclusive);
                driverPin.Write(GpioPinValue.Low);
                driverPin.SetDriveMode(GpioPinDriveMode.Output);

                if (echoPin.IsDriveModeSupported(GpioPinDriveMode.InputPullUp))
                {
                    echoPin.SetDriveMode(GpioPinDriveMode.InputPullUp);
                }
                else
                {
                    echoPin.SetDriveMode(GpioPinDriveMode.Input);
                }


                changeReader = new GpioChangeReader(echoPin);//here is the error coming
                changeReader.Polarity = GpioChangePolarity.Both; // one measurement results in one rising and one falling edge
                changeReader.Start();

                // we use the stopwatch to time the trigger pulse
                stopwatch = Stopwatch.StartNew();
                stopwatch.Start();
            }
            catch (Exception r1) {
            }
        }

        public void Trigger()
        {
            changeReader.Clear();
            var a = changeReader.WaitForItemsAsync(2); // two edges, measure the time between
            a.Completed = GpioValueChanged;

            // trigger an echo
            driverPin.Write(GpioPinValue.High);
            Wait(0.1); // datasheet says 10us would do but this too is fine
            driverPin.Write(GpioPinValue.Low);
        }

        void GpioValueChanged(IAsyncAction action, AsyncStatus status)
        {
            var events = changeReader.GetAllItems();
            if (events.Count < 2)
            {
                // fail silently
                return;
            }
            var first = events[0];
            var second = events[1];
            lastDelay = (second.RelativeTime - first.RelativeTime).TotalSeconds;
        }

        public double GetCentimeters()
        {
            return 100.0 * lastDelay * 340.0 / 2.0; // sound speed 340m/s, divide by two as it's both ways
        }

        // busy wait for milliseconds
        // source: http://www.iot-developer.net/windows-iot/uwp-programming-in-c/timer-and-timing/stopwatch
        private void Wait(double milliseconds)
        {
            long initialTick = stopwatch.ElapsedTicks;
            long initialElapsed = stopwatch.ElapsedMilliseconds;
            double desiredTicks = milliseconds / 1000.0 * Stopwatch.Frequency;
            double finalTick = initialTick + desiredTicks;
            while (stopwatch.ElapsedTicks < finalTick) ; // busy wait
        }
    }
}

Answer 1

请告诉我您是否在应用程序中为Lightning Provider添加了

capabilities？

<iot:Capability Name="lowLevelDevices" />
<DeviceCapability Name="109b86ad-f53d-4b76-aa5f-821e2ddf2141"/>

请参考How to add the library LightingProvider to your application。如果仍然无法解决问题，则可以尝试使用默认的收件箱驱动程序来测试问题。