GpioDriver for other boards and virtual GpioController and virtual GpioPin

This project contains some full function(PULL-UP, PULL-DOWN) generic GPIO drivers, and it can provide faster GPIO access.

Documentation

• For Allwinner SoCs: SunxiDriver
• For Rockchip SoCs: RockchipDriver

Usage of virtual GpioController and virtual GpioPin

When you have multiple GpioControllers and want to use them together in a specific binding, the VirtualGpioController allows to create a GpioController from a set of GpioPins already open from different controllers. Usage is straight forward and the class is fully compatible with a normal GpioController.

// Create pins from 2 different GpioControllers
var pinFromA = gpioControllerA.Open(42, PinMode.Output);
var pinFromB = gpioControllerB.Open(24, PinMode.Input);
var pinFromC = gpioControllerC.Open(12, PinMode.Input);
VirtualGpioController gpio = new();
// pin number will be 0 in this case
gpio.Add(pinFromA);
// pin number will be 12 in this case
gpio.Add(12, pinFromB);
// the pin number will be 13 in this case
gpio.Add(pinFromC);

When adding an existing GpioPin, by default, the new pin allocation will directly follow the higher pin number already existing. You can also use this method to change the numbering of your board. Note that the VirtualGpioController is only operating in the logical numbering.

Board specific drivers

Board	Driver
Orange Pi 4	OrangePi4Driver
Orange Pi 5	OrangePi5Driver
Orange Pi 5B	OrangePi5BDriver
Orange Pi 5 Plus	OrangePi5PlusDriver
Orange Pi 5 Pro	OrangePi5ProDriver
Orange Pi 5 Max	OrangePi5MaxDriver
Orange Pi 5 Ultra	OrangePi5UltraDriver
Orange Pi Lite	OrangePiLiteDriver
Orange Pi Lite 2	OrangePiLite2Driver
Orange Pi Zero	OrangePiZeroDriver
Orange Pi Zero 2	OrangePiZero2Driver
Rock Pi 4B Plus	RockPi4BPlusDriver
Orange Pi PC	OrangePiPCDriver

Benchmarks

The test uses different GPIO drivers to quickly switch the state of GPIO, and uses an oscilloscope to measure the average frequency of GPIO externally.

SunxiDriver

Benchmarking with Orange Pi Zero, select GPIO 6 (Logical). The operating system is Armbian buster, Linux kernel version is 5.10.16, and .NET version is 5.0.3.

Drivers	Language	Library Version	Test Date	Average Frequency
SunxiDriver	C#	-	2020-02-20	185 KHz
SysFsDriver	C#	System.Device.Gpio 1.3.0	2020-02-20	692 Hz
LibGpiodDriver	C#	System.Device.Gpio 1.3.0 - libgpiod 1.2-3	2020-02-20	81 KHz
wiringOP	C	35de015	2020-02-22	1.10 MHz

RockchipDriver

Benchmarking with Orange Pi 4, select GPIO 150 (Logical). The operating system is Armbian buster, Linux kernel version is 5.10.16, and .NET version is 5.0.3.

Drivers	Language	Library Version	Test Date	Average Frequency
RockchipDriver	C#	-	2020-02-22	516 KHz
SysFsDriver	C#	System.Device.Gpio 1.3.0	2020-02-22	4.27 KHz
LibGpiodDriver	C#	System.Device.Gpio 1.3.0 - libgpiod 1.2-3	2020-02-22	174 KHz
wiringOP	C	35de015	2020-02-22	584 KHz

Usage

Hardware required

• Orange Pi Zero
• Switch
• Male/Female Jumper Wires

Circuit

• Switch 1 - Board Pin7 (GPIO 6)
• Switch 2 - GND

Code

using System;
using System.Device.Gpio;
using Iot.Device.BoardLed;
using Iot.Device.Gpio.Drivers;

// Set debounce delay to 5ms
int debounceDelay = 50000;
int pin = 7;

Console.WriteLine($"Let's blink an on-board LED!");

using GpioController controller = new GpioController(new OrangePiZeroDriver());
using BoardLed led = new BoardLed("orangepi:red:status");

controller.OpenPin(pin, PinMode.InputPullUp);
led.Trigger = "none";
Console.WriteLine($"GPIO pin enabled for use: {pin}.");
Console.WriteLine("Press any key to exit.");

while (!Console.KeyAvailable)
{
    if (Debounce())
    {
        // Button is pressed
        led.Brightness = 1;
    }
    else
    {
        // Button is unpressed
        led.Brightness = 0;
    }
}

bool Debounce()
{
    long debounceTick = DateTime.Now.Ticks;
    PinValue buttonState = controller.Read(pin);

    do
    {
        PinValue currentState = controller.Read(pin);

        if (currentState != buttonState)
        {
            debounceTick = DateTime.Now.Ticks;
            buttonState = currentState;
        }
    }
    while (DateTime.Now.Ticks - debounceTick < debounceDelay);

    if (buttonState == PinValue.Low)
    {
        return true;
    }
    else
    {
        return false;
    }
}