Trouble with GPIO interrupt handling on Raspberry Pi 4 with Windows IoT

Hi everyone, I'm working on a project that requires real-time input from a sensor connected to a GPIO pin on a Raspberry Pi 4 running Windows IoT Enterprise. I'm trying to implement interrupt handling to detect changes on a specific pin. I'm using the `Windows.Devices.Gpio` namespace and have successfully opened the GPIO controller and the specific pin. However, when I try to register an interrupt handler using `GpioPin.ValueChanged`, the interrupt doesn't seem to be firing consistently, or at all in some cases. Here's a snippet of my code: ```csharp // ... opening GpioController and GpioPin ... pin.SetDriveMode(GpioPinDriveMode.InputPullUp); pin.DebounceTimeout = TimeSpan.FromMilliseconds(50); // Added debounce pin.ValueChanged += Pin_ValueChanged; // ... rest of the application ... private void Pin_ValueChanged(GpioPin sender, GpioPinValueChangedEventArgs args) { Debug.WriteLine($"Pin {sender.PinNumber} changed: {args.Edge}"); // My logic to handle the interrupt } ``` I've tested the sensor and wiring independently, and they seem to be working fine. I've also tried different GPIO pins and different drive modes. Is there any known issue with GPIO interrupts on Windows IoT on Raspberry Pi 4, or am I missing a crucial step in the setup? Any help or suggestions would be greatly appreciated!

Hi IoT_Enthusiast, I encountered a similar issue a few months back with a Raspberry Pi 3B+ and Windows IoT Core. It turned out to be a combination of things for me: 1. **Driver Issues:** Ensure you have the latest stable build of Windows IoT Enterprise installed, and that all relevant drivers for the Raspberry Pi are up to date. Sometimes, older drivers can cause unpredictable behavior with hardware interfaces. 2. **Threading:** Are you sure the `Pin_ValueChanged` event handler isn't blocking or being called on a thread that gets terminated? For UWP/IoT applications, event handlers might be invoked on background threads, and if not managed carefully, could lead to issues. Consider using `CoreDispatcher.RunAsync` if you need to update the UI. 3. **Interrupt Configuration:** While `ValueChanged` is the standard way, have you explored the lower-level `GpioController.OpenPin` with `GpioSharingMode.Exclusive` and then manually checking pin state? It's more cumbersome but can help debug if the event system is the culprit. 4. **Power Management:** Sometimes, aggressive power saving settings on the IoT device can interfere with hardware interrupts. Check the power plan settings. For my case, updating the Windows build and explicitly ensuring my interrupt handler was quick and didn't perform heavy lifting (deferring that to a separate task) resolved the problem. Hope this helps!

Thanks John_Doe_Dev for the quick response and suggestions! I've checked my Windows IoT Enterprise build, and it's the latest stable version. I'll double-check the specific drivers for the RPi 4 though, that's a good point. Regarding threading, my `Pin_ValueChanged` handler is quite simple – it just writes to a `Debug.WriteLine`. I'm not directly updating any UI elements from there. I've tested running the application from Visual Studio with debugging enabled, and the `Debug.WriteLine` output is inconsistent. It seems to work for a while, then stops firing. I haven't explored the lower-level `GpioController.OpenPin` with `Exclusive` mode yet. I'll try that as a debugging step to see if I can get any signal at all. Power management is something I hadn't considered. I'll investigate the power plan settings on the RPi. I'll try these steps and report back. Thanks again for the detailed advice!