C ＃ nanoframework lighting and key esp32

It was supposed to be a big weekend ,WIFI and Web Web pages and so on , Why did it take two days , And after chatting with foreign friends , It was found that there was a problem with the firmware , After communicating with the boss in the evening, I found , original ESP32S There is a problem with the official firmware of , Can't do it .

therefore , If it is recommended to buy ESP32, Just don't bring any models .

The new board I bought is already on the way , We can't follow up until the board comes .

At present, we can also do some simple , Just do it first .

Basic knowledge of embedded

If it's for SCM , Embedded less understood , It is still necessary to have a deep understanding of the basic knowledge of hardware .

You can refer to 《 Zero dead angle play STM32—F429 Challenger .pdf 》 To learn most of the relevant knowledge , Just look at the basic part , Of course, it's better to watch more .

although , The boards are different , however , The basic knowledge is similar , They are all in the same way .

such as STM32 It can reach more than 100 pins , and ESP32 Maybe it's just 40 Left and right pins , In addition to the built-in WIFI Already occupied , Most of the IO The mouth has been drawn out , You can design it at the hardware level by yourself .

On the development board , Generally, such pins will be led out separately , For development and testing .

GPIO

What is GPIO, english : General-purpose input/output Chinese is Short for general purpose input and output , Simply speaking , Namely CPU Controllable pins , adopt CPU Chip GPIO Pins and external devices ( The sensor is ,AD Collection equipment ) Connect , So as to realize external communication 、 Control and data acquisition functions .

GPIO Basic inputs and outputs

Basic input

The most basic output , It is to detect the external input level , such as , Judge whether the current key is pressed down .

Basic output

The most basic output is to control the chip pin output high , Low level , Switch control is realized , such as GPIO Pin into LED The lamp , Then you can control LED The light goes on and off . Connect to relay or triode , Then the switch or on-off of external high-power circuit can be controlled by relay or triode .

GPIO The illustration

That's all GPIO The schematic diagram of , Of course , The hardware may be upgraded , however , The general principle is the same .

For an in-depth explanation, you can read the introduction in the book and online materials , Here I'll talk about my general explanation .

IO The mouth itself shows two meanings , Input and output .

therefore , The function of this circuit is to try to ensure its input and output stability , Security , reliable .

Of course , It is safer and more reliable to pull up from the outside , It's still weak , voltage 3.3V about , The current is estimated to be smaller , Prefer to control signal level .

therefore , Want to get external information , Or output information to the outside , You can roughly know from the figure , The picture also shows these two ways , One is input , One is output .

C# Achieve lighting and get button items

Board related information

My current board is ESP32S, Found the official , Finally found the information , The address is as follows :

https://docs.ai-thinker.com/esp32/boards/nodemcu_32s

Most of the information can be referred to , Can download

The following is its functional pin diagram

The following is its full circuit diagram

We need to light the lights , And the buttons , So we need to find these two functions IO What are they .

LED and Button Of GPIO

It can be seen from the picture that LED Of GPIO yes IO2 (GPIO 2 It means , That's the second one IO Pin )

Press the key , One is EN, It's the switch enabling key of the board , This key , Can not use , We can only use another , That's it IO0, The first 0 Key .

Code related

Need to add several Nuget package

Install-Package nanoFramework.Hardware.Esp32 -Version 1.3.6.7
Install-Package nanoFramework.Runtime.Events -Version 1.10.0
Install-Package nanoFramework.System.Device.Gpio -Version 1.0.4

then , Add point code , The logic is simple , Press down Boot Key , Turn on the light , Release the button , Put out the light .

public class Program
{
    public static GpioPin led;
    public static GpioPin button;
    public static void Main()
    {
        var gpioController = new GpioController();
        button = gpioController.OpenPin(Gpio.IO00, PinMode.Input);
        led = gpioController.OpenPin(Gpio.IO02, PinMode.Output);
        button.ValueChanged += Button_ValueChanged;

        while (true)
        {
            Thread.Sleep(1000);
        }
    }

    private static void Button_ValueChanged(object sender, PinValueChangedEventArgs e)
    {
        Debug.WriteLine(" Key events  : " + e.ChangeType.ToString());
        Debug.WriteLine(" Key current value : " + button.Read());

        if (e.ChangeType != PinEventTypes.Rising)
        {
            // Press to turn on the light 
            led.Write(PinValue.High);
        }
        else
        {
            // Release your hand and turn off the light 
            led.Write(PinValue.Low);
        }
    }
}

Result of operation

It can be seen clearly , When you press the key , The current value is Low, After loosening , yes High.

Above is a small picture of pressing the key .

I tried it again and again , If it is started, it is probably 2 Seconds, the key is valid . Logic of keys and lights , The reaction is also very fast .

summary

On the whole , It is much easier to operate , You can also debug , That is, the board should be consistent with the firmware , otherwise , There will be many small problems , Need to overcome .

Code address

https://github.com/kesshei/NanoFreamworkKeyOrButtonDemo.git

https://gitee.com/kesshei/NanoFreamworkKeyOrButtonDemo.git

reading

One button three times ！, Thank you for your support , Your support is my motivation !