templete.txt

bool loadConfig()
{
    File configFile = SPIFFS.open("/config.json", "r");
    if (!configFile)
    {
        Serial.println("Failed to open config file");
        return false;
    }

    size_t size = configFile.size();
    if (size > 1024)
    {
        Serial.println("Config file size is too large");
        return false;
    }

    // Allocate a buffer to store contents of the file.
    std::unique_ptr<char[]> buf(new char[size]);

    // We don't use String here because ArduinoJson library requires the input
    // buffer to be mutable. If you don't use ArduinoJson, you may as well
    // use configFile.readString instead.
    configFile.readBytes(buf.get(), size);

    StaticJsonDocument<200> doc;
    auto error = deserializeJson(doc, buf.get());
    if (error)
    {
        Serial.println("Failed to parse config file");
        return false;
    }

    const char *serverName = doc["serverName"];
    const char *accessToken = doc["accessToken"];

    // Real world application would store these values in some variables for
    // later use.

    Serial.print("Loaded serverName: ");
    Serial.println(serverName);
    Serial.print("Loaded accessToken: ");
    Serial.println(accessToken);
    return true;
}

bool saveConfig()
{
    StaticJsonDocument<200> doc;
    doc["serverName"] = "api.example.com";
    doc["accessToken"] = "128du9as8du12eoue8da98h123ueh9h98";

    File configFile = SPIFFS.open("/config.json", "w");
    if (!configFile)
    {
        Serial.println("Failed to open config file for writing");
        return false;
    }

    serializeJson(doc, configFile);
    return true;
}

void setupExpamle()
{
    Serial.begin(115200);
    Serial.println("");
    delay(1000);
    Serial.println("Mounting FS...");

    if (!SPIFFS.begin())
    {
        Serial.println("Failed to mount file system");
        return;
    }

    if (!saveConfig())
    {
        Serial.println("Failed to save config");
    }
    else
    {
        Serial.println("Config saved");
    }

    if (!loadConfig())
    {
        Serial.println("Failed to load config");
    }
    else
    {
        Serial.println("Config loaded");
    }
}



/// virtual switch 

if(switch_status_12==(!digitalRead(INPIN_12)))// to read the status of physical switch
     {
        // send_status=0;
     }
  else
     {
      switch_status_12=(!digitalRead(INPIN_12));
      Serial.println("Status 12 ");
      send_status_12=1;
     }
     


     //Pin Out of esp32 

GPIO	Input	Output	Notes
0	pulled up	OK	outputs PWM signal at boot
1	TX pin	OK	debug output at boot
2	OK	OK	connected to on-board LED
3	OK	RX pin	HIGH at boot
4	OK	OK	
5	OK	OK	outputs PWM signal at boot
6	x	x	connected to the integrated SPI flash
7	x	x	connected to the integrated SPI flash
8	x	x	connected to the integrated SPI flash
9	x	x	connected to the integrated SPI flash
10	x	x	connected to the integrated SPI flash
11	x	x	connected to the integrated SPI flash
12	OK	OK	boot fail if pulled high
13	OK	OK	
14	OK	OK	outputs PWM signal at boot
15	OK	OK	outputs PWM signal at boot
16	OK	OK	
17	OK	OK	
18	OK	OK	
19	OK	OK	
21	OK	OK	
22	OK	OK	
23	OK	OK	
25	OK	OK	
26	OK	OK	
27	OK	OK	
32	OK	OK	
33	OK	OK	
34	OK		input only
35	OK		input only
36	OK		input only
39	OK		input only

Input only pins
GPIOs 34 to 39 are GPIs – input only pins. These pins don’t have internal pull-ups or pull-down resistors. They can’t be used as outputs, so use these pins only as inputs:

GPIO 34
GPIO 35
GPIO 36
GPIO 39

SPI flash integrated on the ESP-WROOM-32
GPIO 6 to GPIO 11 are exposed in some ESP32 development boards. However, these pins are connected to the integrated SPI flash on the ESP-WROOM-32 chip and are not recommended for other uses. So, don’t use these pins in your projects:

GPIO 6 (SCK/CLK)
GPIO 7 (SDO/SD0)
GPIO 8 (SDI/SD1)
GPIO 9 (SHD/SD2)
GPIO 10 (SWP/SD3)
GPIO 11 (CSC/CMD)

Analog to Digital Converter (ADC)
The ESP32 has 18 x 12 bits ADC input channels (while the ESP8266 only has 1x 10 bits ADC). These are the GPIOs that can be used as ADC and respective channels:

ADC1_CH0 (GPIO 36)
ADC1_CH1 (GPIO 37)
ADC1_CH2 (GPIO 38)
ADC1_CH3 (GPIO 39)
ADC1_CH4 (GPIO 32)
ADC1_CH5 (GPIO 33)
ADC1_CH6 (GPIO 34)
ADC1_CH7 (GPIO 35)
ADC2_CH0 (GPIO 4)
ADC2_CH1 (GPIO 0)
ADC2_CH2 (GPIO 2)
ADC2_CH3 (GPIO 15)
ADC2_CH4 (GPIO 13)
ADC2_CH5 (GPIO 12)
ADC2_CH6 (GPIO 14)
ADC2_CH7 (GPIO 27)
ADC2_CH8 (GPIO 25)
ADC2_CH9 (GPIO 26)


Note: ADC2 pins cannot be used when Wi-Fi is used. So, if you’re using Wi-Fi and you’re having trouble getting the value from an ADC2 GPIO, you may consider using an ADC1 GPIO instead, that should solve your problem.

Digital to Analog Converter (DAC)
There are 2 x 8 bits DAC channels on the ESP32 to convert digital signals into analog voltage signal outputs. These are the DAC channels:

DAC1 (GPIO25)
DAC2 (GPIO26)
RTC GPIOs
There is RTC GPIO support on the ESP32. The GPIOs routed to the RTC low-power subsystem can be used when the ESP32 is in deep sleep. These RTC GPIOs can be used to wake up the ESP32 from deep sleep when the Ultra Low Power (ULP) co-processor is running. The following GPIOs can be used as an external wake up source.

RTC_GPIO0 (GPIO36)
RTC_GPIO3 (GPIO39)
RTC_GPIO4 (GPIO34)
RTC_GPIO5 (GPIO35)
RTC_GPIO6 (GPIO25)
RTC_GPIO7 (GPIO26)
RTC_GPIO8 (GPIO33)
RTC_GPIO9 (GPIO32)
RTC_GPIO10 (GPIO4)
RTC_GPIO11 (GPIO0)
RTC_GPIO12 (GPIO2)
RTC_GPIO13 (GPIO15)
RTC_GPIO14 (GPIO13)
RTC_GPIO15 (GPIO12)
RTC_GPIO16 (GPIO14)
RTC_GPIO17 (GPIO27)

I2C
The ESP32 has two I2C channels and any pin can be set as SDA or SCL. When using the ESP32 with the Arduino IDE, the default I2C pins are:

GPIO 21 (SDA)
GPIO 22 (SCL)


SPI
By default, the pin mapping for SPI is:

SPI	MOSI	MISO	CLK	CS
VSPI	GPIO 23	GPIO 19	GPIO 18	GPIO 5
HSPI	GPIO 13	GPIO 12	GPIO 14	GPIO 15
Interrupts
All GPIOs can be configured as interrupts.

Enable (EN)
Enable (EN) is the 3.3V regulator’s enable pin. It’s pulled up, so connect to ground to disable the 3.3V regulator. This means that you can use this pin connected to a pushbutton to restart your ESP32, for example.

ESP32 Built-In Hall Effect Sensor
The ESP32 also features a built-in hall effect sensor that detects changes in the magnetic field in its surroundings.

https://randomnerdtutorials.com/esp32-pinout-reference-gpios/




     //End of pinout esp32