STM32: WiFiNINA with ESP32 WiFi Co-Processor

Renzo Mischianti

2 years ago

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We have already looked at how to add a wiring connection to an STM32, but sometimes the only solution is a Wireless or WiFi connection.

STM32 black blue pill and ESP32 WiFi Co-Processor with WiFiNINA

I tried to find the best solution, which for me means functionality and cheap, so I immediately discarded the use of AT esp8266, which is very tedious, and NINA_B302_ublox or similar, which are very expensive.

But the solution is given from my best factory, the Adafruit, which created a device named Airlift that simply uses a basic ESP32-WROOM-32 to give a complete and powerful WiFi solution to a wide variety of device.

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Firmware and library

We can’t use the original WiFiNINA, and original NINA-FW firmware, but the Adafruit one.

We must download the Adafruit WiFiNINA from this link.

WiFiNINA-master.zip

After downloading, copy It into the Arduino library folder.

And the Adafruit nina firmware from here.

nina-fw

To upload the firmware in the ESP32, you must download and use esptool by following these steps.

Download Python.

ESP Tools Install Python and add It to path

Install It, and remember to add It to the PATH.
Run the following in your terminal:
pip3 install esptool
Uploading nina-fw with esptool

If you’re using macOS or Linux – run the following command, replacing /dev/ttyACM0 with the serial port of your board and NINA_W102-1.7.4 with the binary file to flashing to the ESP32.

esptool.py --port /dev/ttyACM0 --before no_reset --baud 115200 write_flash 0 NINA_W102-1.7.4.bin

If you’re using Windows – run the following command, replacing COM7 with the serial port of your board and NINA_W102-1.6.0 with the binary file to flashing to the ESP32

esptool.py --port COM7 --before no_reset --baud 115200 write_flash 0 NINA_W102-1.7.4.bin

Wiring

We are going to test 2 devices, an STM32F103C8 blue-pill, and an STM32F401CC, and first, we will test the solution with a DOIT ESP32 DEV KIT v1, then we are going to use directly (with an adapter) the ESP32-WROOM-32 and ESP32-S.

STM32F103C8 blue pill with a DOIT ESP32 DEV KIT v1 as WiFi Co-Processor

We start with the basic STM32: the Blue-pill, so we can test the resource needed to work.

Pinout STM32 STM32F1 STM32F103 STM32F103C8 low resolution

Here my selection of STM32 STM32F103C8T6 STM32F401 STM32F411 ST-Link v2 ST-Link v2 official

And to simplify the wiring, we are going to use a prototype board for the ESP32.

Here my selection of ESP32 ESP32 Dev Kit v1 - TTGO T-Display 1.14 ESP32 - NodeMCU V3 V2 ESP8266 Lolin32 - NodeMCU ESP-32S - WeMos Lolin32 - WeMos Lolin32 mini - ESP32-CAM programmer - ESP32-CAM bundle - ESP32-WROOM-32 - ESP32-S

To understand the output of nina-fw by Adafruit, we can look at the Airlift schema.

As you can see there are some output and input to configure.

ESP32	Microcontroller	STM32
GPIO05	CS	PA4
GPIO18	SCK	PA5
GPIO23	MISO	PA6
GPIO14	MOSI	PA7
GPIO33	BUSY/READY (IRQ)	PA3
EN (reset on LOW)	RST/EN	PA2
GND	GND	GND
VIN	3.3v

The result is this.

STM32 blue pill and DOIT ESP32 DevKit as WiFi Co-Processor with WiFiNINA: wiring

To power the ESP32 now, I use a USB directly connected to the relative port.

STM32F401CC black pill with an ESP32-WROOM-32 as WiFi Co-Processor

We can use the same configuration with the STM32F4 black pill.

STM32 STM32F401 STM32F401CCU6 pinout low resolution

Here my selection of STM32 STM32F103C8T6 STM32F401 STM32F411 ST-Link v2 ST-Link v2 official

Naturally, we want to use the single ESP32 chip instead of a prototype board. To use the single-chip, we need an adapter and can follow the previous articles about that “ESP32-wroom-32, esp32-S: flash, pinout, specs and IDE configuration“.

Here the programmer Aliexpress adapter esp8266 esp32

The wiring is similar, but we are going to use a single power supply from STM32 with a voltage regulator.

ESP32	Description	STM32
GPIO05	CS	PA4
GPIO18	SCK	PA5
GPIO23	MISO	PA6
GPIO14	MOSI	PA7
GPIO33	BUSY/READY (IRQ)	PA3
EN (reset on LOW)	RST/EN	PA2
GPIO0 (Flash)	Flash	PA1 (not needed)
GND	GND	GND
VIN	3.3v	From 5v to a voltage regulator

The result is in this schema.

STM32 Blue Pill ESP32-WROOM-32 as WiFi Co-Processor WiFiNINA wiring

Here the voltage regulator modules Aliexpress 4 pin - Aliexpress 3 pin

Here the voltage regulator IC AliExpress SMD (AMS1117) - AliExpress 3.3v (LM1117) - AliExpress 5v (7805) - AliExpress 9v (7809)AliExpress 12v (7812) - AliExpress 3.3v TO-92 (78L33)

Code

Now, after downloading the Adafruit WiFiNINA, download and upload to esp32 the nina-fw and make all wiring, we can try to test if the Co-processor communicates well.

Check firmware sketch

First of all, the sketch asks for the version of the firmware installed on the ESP32.

/*
 * This example check if the firmware loaded on the NINA module
 * is updated.
 *
 * modified by Renzo Mischianti <www.mischianti.org>
 *
 * www.mischianti.org
 *
 */
#include <SPI.h>
#include <WiFiNINA.h>

// Configure the pins used for the ESP32 connection
#if defined(ADAFRUIT_FEATHER_M4_EXPRESS) || \
  defined(ADAFRUIT_FEATHER_M0) || \
  defined(ADAFRUIT_FEATHER_M0_EXPRESS) || \
  defined(ARDUINO_AVR_FEATHER32U4) || \
  defined(ARDUINO_NRF52840_FEATHER) || \
  defined(ADAFRUIT_ITSYBITSY_M0) || \
  defined(ADAFRUIT_ITSYBITSY_M4_EXPRESS) || \
  defined(ARDUINO_AVR_ITSYBITSY32U4_3V) || \
  defined(ARDUINO_NRF52_ITSYBITSY)
  // Configure the pins used for the ESP32 connection
  #define SPIWIFI       SPI  // The SPI port
  #define SPIWIFI_SS    13   // Chip select pin
  #define ESP32_RESETN  12   // Reset pin
  #define SPIWIFI_ACK   11   // a.k.a BUSY or READY pin
  #define ESP32_GPIO0   -1
#elif defined(ARDUINO_AVR_FEATHER328P)
  #define SPIWIFI       SPI  // The SPI port
  #define SPIWIFI_SS     4   // Chip select pin
  #define ESP32_RESETN   3   // Reset pin
  #define SPIWIFI_ACK    2   // a.k.a BUSY or READY pin
  #define ESP32_GPIO0   -1
#elif defined(TEENSYDUINO)
  #define SPIWIFI       SPI  // The SPI port
  #define SPIWIFI_SS     5   // Chip select pin
  #define ESP32_RESETN   6   // Reset pin
  #define SPIWIFI_ACK    9   // a.k.a BUSY or READY pin
  #define ESP32_GPIO0   -1
#elif defined(ARDUINO_NRF52832_FEATHER )
  #define SPIWIFI       SPI  // The SPI port
  #define SPIWIFI_SS    16   // Chip select pin
  #define ESP32_RESETN  15   // Reset pin
  #define SPIWIFI_ACK    7   // a.k.a BUSY or READY pin
  #define ESP32_GPIO0   -1
#elif defined(ARDUINO_ARCH_STM32) // Here my STM32 configuration
  #define SPIWIFI       SPI  // The SPI port
  #define SPIWIFI_SS    PA4   // Chip select pin
  #define ESP32_RESETN  PA2   // Reset pin
  #define SPIWIFI_ACK   PA3   // a.k.a BUSY or READY pin
  #define ESP32_GPIO0   -1
#elif !defined(SPIWIFI_SS)   // if the wifi definition isnt in the board variant
  // Don't change the names of these #define's! they match the variant ones
  #define SPIWIFI       SPI
  #define SPIWIFI_SS    10   // Chip select pin
  #define SPIWIFI_ACK    7   // a.k.a BUSY or READY pin
  #define ESP32_RESETN   5   // Reset pin
  #define ESP32_GPIO0   -1   // Not connected
#endif

void setup() {
  // Initialize serial
  Serial.begin(9600);
  while (!Serial) {
    ; // wait for serial port to connect. Needed for native USB port only
  }

  // Print a welcome message
  Serial.println("WiFiNINA firmware check.");
  Serial.println();

  // Set up the pins!
  WiFi.setPins(SPIWIFI_SS, SPIWIFI_ACK, ESP32_RESETN, ESP32_GPIO0, &SPIWIFI);

  // check for the WiFi module:
  if (WiFi.status() == WL_NO_MODULE) {
    Serial.println("Communication with WiFi module failed!");
    // don't continue
    while (true);
  }

  // Print firmware version on the module
  String fv = WiFi.firmwareVersion();
  String latestFv;
  Serial.print("Firmware version installed: ");
  Serial.println(fv);

  latestFv = WIFI_FIRMWARE_LATEST_VERSION;

  // Print required firmware version
  Serial.print("Latest firmware version available : ");
  Serial.println(latestFv);

  // Check if the latest version is installed
  Serial.println();
  if (fv >= latestFv) {
    Serial.println("Check result: PASSED");
  } else {
    Serial.println("Check result: NOT PASSED");
    Serial.println(" - The firmware version on the module do not match the");
    Serial.println("   version required by the library, you may experience");
    Serial.println("   issues or failures.");
  }
}

void loop() {
  // do nothing
}

The sketch It’s the same as the original WiFiNINA except for the possibility to define the pins. This feature is fundamental to using the WiFi on our microcontroller.

  // Set up the pins!
  WiFi.setPins(SPIWIFI_SS, SPIWIFI_ACK, ESP32_RESETN, ESP32_GPIO0, &SPIWIFI);

The output of the sketch is:

Firmware version installed: 1.7.4
Latest firmware version available : 1.2.1

Check result: PASSED

Scan WiFi network sketch

STM32 blue pill: DOIT ESP32 DevKit as WiFi Co-Processor with WiFiNINA

A sketch to find all networks near the device, with the relative RSSI and encryption type.

/*

 This example  prints the board's MAC address, and
 scans for available Wifi networks using the NINA module.
 Every ten seconds, it scans again. It doesn't actually
 connect to any network, so no encryption scheme is specified.

 Circuit:
 * Board with NINA firmware on it (In this case its an Adafruit AirLift)

 created 13 July 2010
 by dlf (Metodo2 srl)
 modified 21 Junn 2012
 by Tom Igoe and Jaymes Dec
 modified 17 May 2022
 by Renzo Mischianti

 */


#include <SPI.h>
#include <WiFiNINA.h>

// Configure the pins used for the ESP32 connection
#if defined(ADAFRUIT_FEATHER_M4_EXPRESS) || \
  defined(ADAFRUIT_FEATHER_M0) || \
  defined(ADAFRUIT_FEATHER_M0_EXPRESS) || \
  defined(ARDUINO_AVR_FEATHER32U4) || \
  defined(ARDUINO_NRF52840_FEATHER) || \
  defined(ADAFRUIT_ITSYBITSY_M0) || \
  defined(ADAFRUIT_ITSYBITSY_M4_EXPRESS) || \
  defined(ARDUINO_AVR_ITSYBITSY32U4_3V) || \
  defined(ARDUINO_NRF52_ITSYBITSY)
  // Configure the pins used for the ESP32 connection
  #define SPIWIFI       SPI  // The SPI port
  #define SPIWIFI_SS    13   // Chip select pin
  #define ESP32_RESETN  12   // Reset pin
  #define SPIWIFI_ACK   11   // a.k.a BUSY or READY pin
  #define ESP32_GPIO0   -1
#elif defined(ARDUINO_AVR_FEATHER328P)
  #define SPIWIFI       SPI  // The SPI port
  #define SPIWIFI_SS     4   // Chip select pin
  #define ESP32_RESETN   3   // Reset pin
  #define SPIWIFI_ACK    2   // a.k.a BUSY or READY pin
  #define ESP32_GPIO0   -1
#elif defined(TEENSYDUINO)
  #define SPIWIFI       SPI  // The SPI port
  #define SPIWIFI_SS     5   // Chip select pin
  #define ESP32_RESETN   6   // Reset pin
  #define SPIWIFI_ACK    9   // a.k.a BUSY or READY pin
  #define ESP32_GPIO0   -1
#elif defined(ARDUINO_NRF52832_FEATHER )
  #define SPIWIFI       SPI  // The SPI port
  #define SPIWIFI_SS    16   // Chip select pin
  #define ESP32_RESETN  15   // Reset pin
  #define SPIWIFI_ACK    7   // a.k.a BUSY or READY pin
  #define ESP32_GPIO0   -1
#elif defined(ARDUINO_ARCH_STM32 )
  #define SPIWIFI       SPI  // The SPI port
  #define SPIWIFI_SS    PA4   // Chip select pin
  #define ESP32_RESETN  PA2   // Reset pin
  #define SPIWIFI_ACK   PA3   // a.k.a BUSY or READY pin
  #define ESP32_GPIO0   -1
#elif !defined(SPIWIFI_SS)   // if the wifi definition isnt in the board variant
  // Don't change the names of these #define's! they match the variant ones
  #define SPIWIFI       SPI
  #define SPIWIFI_SS    10   // Chip select pin
  #define SPIWIFI_ACK    7   // a.k.a BUSY or READY pin
  #define ESP32_RESETN   5   // Reset pin
  #define ESP32_GPIO0   -1   // Not connected
#endif

void printMacAddress(byte mac[]);
void printEncryptionType(int thisType);
void listNetworks();

void setup() {
  //Initialize serial and wait for port to open:
  Serial.begin(9600);
  while (!Serial) {
    ; // wait for serial port to connect. Needed for native USB port only
  }

  Serial.println("WiFi Scanning test");

  // Set up the pins!
  WiFi.setPins(SPIWIFI_SS, SPIWIFI_ACK, ESP32_RESETN, ESP32_GPIO0, &SPIWIFI);

  // check for the WiFi module:
  while (WiFi.status() == WL_NO_MODULE) {
    Serial.println("Communication with WiFi module failed!");
    // don't continue
    delay(10000);
  }
  String fv = WiFi.firmwareVersion();
  Serial.println(fv);
  if (fv < "1.0.0") {
    Serial.println("Please upgrade the firmware");
    while (1) delay(10);
  }
  Serial.println("Firmware OK");

  // print your MAC address:
  byte mac[6];
  WiFi.macAddress(mac);
  Serial.print("MAC: ");
  printMacAddress(mac);
}

void loop() {
  // scan for existing networks:
  Serial.println("Scanning available networks...");
  listNetworks();
  delay(10000);
}

void listNetworks() {
  // scan for nearby networks:
  Serial.println("** Scan Networks **");
  int numSsid = WiFi.scanNetworks();
  if (numSsid == -1) {
    Serial.println("Couldn't get a wifi connection");
    while (true);
  }

  // print the list of networks seen:
  Serial.print("number of available networks:");
  Serial.println(numSsid);

  // print the network number and name for each network found:
  for (int thisNet = 0; thisNet < numSsid; thisNet++) {
    Serial.print(thisNet);
    Serial.print(") ");
    Serial.print(WiFi.SSID(thisNet));
    Serial.print("\tSignal: ");
    Serial.print(WiFi.RSSI(thisNet));
    Serial.print(" dBm");
    Serial.print("\tEncryption: ");
    printEncryptionType(WiFi.encryptionType(thisNet));
  }
}

void printEncryptionType(int thisType) {
  // read the encryption type and print out the name:
  switch (thisType) {
    case ENC_TYPE_WEP:
      Serial.println("WEP");
      break;
    case ENC_TYPE_TKIP:
      Serial.println("WPA");
      break;
    case ENC_TYPE_CCMP:
      Serial.println("WPA2");
      break;
    case ENC_TYPE_NONE:
      Serial.println("None");
      break;
    case ENC_TYPE_AUTO:
      Serial.println("Auto");
      break;
    case ENC_TYPE_UNKNOWN:
    default:
      Serial.println("Unknown");
      break;
  }
}


void printMacAddress(byte mac[]) {
  for (int i = 5; i >= 0; i--) {
    if (mac[i] < 16) {
      Serial.print("0");
    }
    Serial.print(mac[i], HEX);
    if (i > 0) {
      Serial.print(":");
    }
  }
  Serial.println();
}

You can use the WiFiNINA library to discover all networks, and the result in my case is:

Scanning available networks...
** Scan Networks **
number of available networks:6
0) reef-casa-sopra	Signal: -49 dBm	Encryption: WPA2
1) reef-casa-orto	Signal: -69 dBm	Encryption: WPA2
2) reef-casa-centro	Signal: -78 dBm	Encryption: WPA2
3) reef-casa-centro	Signal: -83 dBm	Encryption: WPA2
4) reef-casa-sotto	Signal: -87 dBm	Encryption: WPA2
5) TIM-18355607	Signal: -91 dBm	Encryption: WPA2

Simple Web Server

Now we are going to create a basic web server that responds on the root of the device.

STM32F4 black pill: ESP32-WROOM-32 as WiFi Co-Processor with WiFiNINA

Here is the simple sketch.

/*
  Simple WiFi Web Server
  You must add your SSID and PASSWD.
  You can open in the browser the IP given in the standard output
  and the device response with a row web page that give you the IP
  and the time in milliseconds.
  The page refresh every 5 seconds.

  by Renzo Mischianti <www.mischianti.org>

  https://www.mischianti.org

 */


#include <SPI.h>
#include <WiFiNINA.h>

#define SPIWIFI       SPI  // The SPI port
#define SPIWIFI_SS    PB0   // Chip select pin
#define ESP32_RESETN  PA2   // Reset pin
#define SPIWIFI_ACK   PA3   // a.k.a BUSY or READY pin
#define ESP32_GPIO0   -1	// or PA1 but not used

#define SECRET_SSID "<YOUR-SSID>";
#define SECRET_PASS  "<YOUR-PASSWD>";


///////please enter your sensitive data in the Secret tab/arduino_secrets.h
char ssid[] = SECRET_SSID;        // your network SSID (name)
char pass[] = SECRET_PASS;    // your network password (use for WPA, or use as key for WEP)
int keyIndex = 0;                 // your network key index number (needed only for WEP)

int status = WL_IDLE_STATUS;

WiFiServer server(80);

void printWifiStatus();

void setup() {
  //Initialize serial and wait for port to open:
  Serial.begin(9600);
  while (!Serial) {
    ; // wait for serial port to connect. Needed for native USB port only
  }

  WiFi.setPins(SPIWIFI_SS, SPIWIFI_ACK, ESP32_RESETN, ESP32_GPIO0, &SPIWIFI);

  // Print a welcome message
  Serial.println("WiFiNINA firmware check.");
  Serial.println();

  // check for the WiFi module:
  if (WiFi.status() == WL_NO_MODULE) {
    Serial.println("Communication with WiFi module failed!");
    // don't continue
    while (true);
  }

  // Print firmware version on the module
  String fv = WiFi.firmwareVersion();
  String latestFv;
  Serial.print("Firmware version installed: ");
  Serial.println(fv);

  latestFv = WIFI_FIRMWARE_LATEST_VERSION;

  // Print required firmware version
  Serial.print("Latest firmware version available : ");
  Serial.println(latestFv);

  // Check if the latest version is installed
  Serial.println();
  if (fv >= latestFv) {
    Serial.println("Check result: PASSED");
  } else {
    Serial.println("Check result: NOT PASSED");
    Serial.println(" - The firmware version on the module do not match the");
    Serial.println("   version required by the library, you may experience");
    Serial.println("   issues or failures.");
  }


  // check for the WiFi module:
  if (WiFi.status() == WL_NO_MODULE) {
    Serial.println("Communication with WiFi module failed!");
    // don't continue
    while (true);
  }

  if (fv < WIFI_FIRMWARE_LATEST_VERSION) {
    Serial.println("Please upgrade the firmware");
  }

  // attempt to connect to WiFi network:
  while (status != WL_CONNECTED) {
    Serial.print("Attempting to connect to SSID: ");
    Serial.println(ssid);
    // Connect to WPA/WPA2 network. Change this line if using open or WEP network:
    status = WiFi.begin(ssid, pass);

    // wait 10 seconds for connection:
    for (int i = 10;i>0;i--){
      delay(1000);
      Serial.print(" . ");
      Serial.print(i);
    }
    Serial.println();
  }
  Serial.println(" OK");

  server.begin();
  // you're connected now, so print out the status:
  printWifiStatus();
}

void loop() {
  // listen for incoming clients
  WiFiClient client = server.available();
  if (client && client.connected()) {
    Serial.println("new client");
    // an HTTP request ends with a blank line
    bool currentLineIsBlank = true;
    while (client.connected()) {
      if (client.available()) {
        char c = client.read();
        Serial.write(c);
        // if you've gotten to the end of the line (received a newline
        // character) and the line is blank, the HTTP request has ended,
        // so you can send a reply
        if (c == '\n' && currentLineIsBlank) {
          Serial.println("Start response!");

          // send a standard HTTP response header
          client.println(F("HTTP/1.1 200 OK"));
          client.println(F("Content-Type: text/html"));
          client.println(F("Connection: close"));  // the connection will be closed after completion of the response
          client.println(F("Refresh: 5"));  // refresh the page automatically every 5 sec
          client.println();
          client.println(F("<!DOCTYPE HTML>"));
           client.println(F("<html>"));
           client.println(F("<body>"));

           client.println(F("<h2>STM32 WiFiNINA server</h2>"));
           client.println("<br /><br />");

           client.println("Refresh every 5 seconds<br />");

           client.print("IP address:");WiFi.localIP().printTo(client);
           client.println("<br /><br />");

           client.print("millis ");
           client.print(millis());
           client.println("<br />");

           client.println("</body>");
           client.println("</html>");
          Serial.println("Stop response!");

          // client.flush();
          break;
        }
        if (c == '\n') {
          // you're starting a new line
          currentLineIsBlank = true;
        } else if (c != '\r') {
          // you've gotten a character on the current line
          currentLineIsBlank = false;
        }
      }
    }
    // give the web browser time to receive the data
    delay(1);

    // close the connection:
    client.stop();
    // server.flush();
    Serial.println("client disconnected");
    delay(1000);
  }
}

void printWifiStatus() {
  // print the SSID of the network you're attached to:
  Serial.print("SSID: ");
  Serial.println(WiFi.SSID());

  // print your board's IP address:
  IPAddress ip = WiFi.localIP();
  Serial.print("IP Address: ");
  Serial.println(ip);

  // print the received signal strength:
  long rssi = WiFi.RSSI();
  Serial.print("signal strength (RSSI):");
  Serial.print(rssi);
  Serial.println(" dBm");
}

In the sketch, we are going to activate a server on port 80 (standard for HTTP protocol).

WiFiServer server(80);

Then in the loop, we constantly check if there is a client request.

  WiFiClient client = server.available();

If we find a client and It’s connected, we are going to read the request.

    while (client.connected()) {
      if (client.available()) {
        char c = client.read();
        Serial.write(c);

When the request is finished we are going to print the response.

        if (c == '\n' && currentLineIsBlank) {
          Serial.println("Start response!");

          // send a standard HTTP response header
          client.println(F("HTTP/1.1 200 OK"));
          client.println(F("Content-Type: text/html"));
          client.println(F("Connection: close"));  // the connection will be closed after completion of the response
          client.println(F("Refresh: 5"));  // refresh the page automatically every 5 sec
          client.println();
          client.println(F("<!DOCTYPE HTML>"));
           client.println(F("<html>"));
           client.println(F("<body>"));

           client.println(F("<h2>STM32 WiFiNINA server</h2>"));
           client.println("<br /><br />");

           client.println("Refresh every 5 seconds<br />");

           client.print("IP address:");WiFi.localIP().printTo(client);
           client.println("<br /><br />");

           client.print("millis ");
           client.print(millis());
           client.println("<br />");

           client.println("</body>");
           client.println("</html>");
          Serial.println("Stop response!");

          // client.flush();
          break;
        }

The console output at startup is

WiFiNINA firmware check.

Firmware version installed: 1.7.4
Latest firmware version available : 1.2.1

Check result: PASSED
Attempting to connect to SSID: reef-casa-sopra
 . 10 . 9 . 8 . 7 . 6 . 5 . 4 . 3 . 2 . 1
 OK
SSID: reef-casa-sopra
IP Address: 192.168.1.143
signal strength (RSSI):-45 dBm

When you open the URL http://192.168.1.143 in the browser the result is

In the console, It prints the request and the alert of response.

new client
GET / HTTP/1.1
Host: 192.168.1.143
Connection: keep-alive
Upgrade-Insecure-Requests: 1
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/101.0.4951.67 Safari/537.36
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.9
Accept-Encoding: gzip, deflate
Accept-Language: it-IT,it;q=0.9,en-US;q=0.8,en;q=0.7,zh-CN;q=0.6,zh;q=0.5
 
Start response!
Stop response!
client disconnected

Simple Web Server with byte array HTML page

First of all, you need an HTML page.

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Demo index page</title>
</head>
<body style="background-color: azure">
    <h1 style="text-align: center">Here the demo page</h1>
    <h2 style="text-align: center">www.mischianti.org</h2>
    <div style="text-align: justify">

    </div>
    Lorem ipsum dolor sit amet, consectetur adipiscing elit. Integer nec odio. Praesent libero. Sed cursus ante dapibus diam. Sed nisi. Nulla quis sem at nibh elementum imperdiet. Duis sagittis ipsum. Praesent mauris. Fusce nec tellus sed augue semper porta. Mauris massa. Vestibulum lacinia arcu eget nulla. Class aptent taciti sociosqu ad litora torquent per conubia nostra, per inceptos himenaeos. Curabitur sodales ligula in libero. Sed dignissim lacinia nunc. Curabitur tortor. Pellentesque nibh. Aenean quam. In scelerisque sem at dolor. Maecenas mattis. Sed convallis tristique sem. Proin ut ligula vel nunc egestas porttitor. Morbi lectus risus, iaculis vel, suscipit quis, luctus non, massa. Fusce ac turpis quis ligula lacinia aliquet. Mauris ipsum. Nulla metus metus, ullamcorper vel, tincidunt sed, euismod in, nibh.
    </div>
</body>
</html>

Copy the HTML code in a file and named It index.html, then use the converter to generate a byte array.

Using a file-to-array converter.

You can use a simple utility to create a compact array from a file, and I add that little program used in esp32-cam, for example,

filetoarray "index.html" > web_index.h

to a repository (I add the exe file that in the original repository isn’t present), and with this program, the file becomes.

// Filename web_index.h
// File stored is index.html, Size: 1187
#define index_html_len 1187
const uint8_t index_html[] PROGMEM = {
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 0x6D, 0x6C, 0x3E
};

I wrote a simple HTML script to simplify the process, upload and copy the result inside the web_index.h file.

Filearray converter

Select file

Generated filearray

You must add the web_index.h file inside the root folder of the Arduino project and now you can stream the file like so

/*
  Simple WiFi Web Server
  You must add your SSID and PASSWD.
  You can open in the browser the IP given in the standard output
  and the device response with a byte array web page that give you the IP
  and the time in milliseconds.
  The page refresh every 5 seconds.

  by Renzo Mischianti <www.mischianti.org>

  https://www.mischianti.org

 */


#include <SPI.h>
#include <WiFiNINA.h>
#include "web_index.h"

#define SPIWIFI       SPI  // The SPI port
#define SPIWIFI_SS    PA4   // Chip select pin
#define ESP32_RESETN  PA2   // Reset pin
#define SPIWIFI_ACK   PA3   // a.k.a BUSY or READY pin
#define ESP32_GPIO0   -1	// or PA1 but not used

#define SECRET_SSID "reef-casa-sopra";
#define SECRET_PASS  "aabbccdd77";


///////please enter your sensitive data in the Secret tab/arduino_secrets.h
char ssid[] = SECRET_SSID;        // your network SSID (name)
char pass[] = SECRET_PASS;    // your network password (use for WPA, or use as key for WEP)
int keyIndex = 0;                 // your network key index number (needed only for WEP)

int status = WL_IDLE_STATUS;

WiFiServer server(80);

void printWifiStatus();

void setup() {
  //Initialize serial and wait for port to open:
  Serial.begin(9600);
  while (!Serial) {
    ; // wait for serial port to connect. Needed for native USB port only
  }

  WiFi.setPins(SPIWIFI_SS, SPIWIFI_ACK, ESP32_RESETN, ESP32_GPIO0, &SPIWIFI);

  // Print a welcome message
  Serial.println("WiFiNINA firmware check.");
  Serial.println();

  // check for the WiFi module:
  if (WiFi.status() == WL_NO_MODULE) {
    Serial.println("Communication with WiFi module failed!");
    // don't continue
    while (true);
  }

  // Print firmware version on the module
  String fv = WiFi.firmwareVersion();
  String latestFv;
  Serial.print("Firmware version installed: ");
  Serial.println(fv);

  latestFv = WIFI_FIRMWARE_LATEST_VERSION;

  // Print required firmware version
  Serial.print("Latest firmware version available : ");
  Serial.println(latestFv);

  // Check if the latest version is installed
  Serial.println();
  if (fv >= latestFv) {
    Serial.println("Check result: PASSED");
  } else {
    Serial.println("Check result: NOT PASSED");
    Serial.println(" - The firmware version on the module do not match the");
    Serial.println("   version required by the library, you may experience");
    Serial.println("   issues or failures.");
  }


  // check for the WiFi module:
  if (WiFi.status() == WL_NO_MODULE) {
    Serial.println("Communication with WiFi module failed!");
    // don't continue
    while (true);
  }

  if (fv < WIFI_FIRMWARE_LATEST_VERSION) {
    Serial.println("Please upgrade the firmware");
  }

  // attempt to connect to WiFi network:
  while (status != WL_CONNECTED) {
    Serial.print("Attempting to connect to SSID: ");
    Serial.println(ssid);
    // Connect to WPA/WPA2 network. Change this line if using open or WEP network:
    status = WiFi.begin(ssid, pass);

    // wait 10 seconds for connection:
    for (int i = 10;i>0;i--){
      delay(1000);
      Serial.print(" . ");
      Serial.print(i);
    }
    Serial.println();
  }
  Serial.println(" OK");

  server.begin();
  // you're connected now, so print out the status:
  printWifiStatus();
}

void loop() {
  // listen for incoming clients
  WiFiClient client = server.available();
  if (client && client.connected()) {
    Serial.println("new client");
    // an HTTP request ends with a blank line
    bool currentLineIsBlank = true;
    while (client.connected()) {
      if (client.available()) {
        char c = client.read();
        Serial.write(c);
        // if you've gotten to the end of the line (received a newline
        // character) and the line is blank, the HTTP request has ended,
        // so you can send a reply
        if (c == '\n' && currentLineIsBlank) {
          Serial.println("Start response!");

          // send a standard HTTP response header
          client.println(F("HTTP/1.1 200 OK"));
          client.println(F("Content-Type: text/html"));
          client.println(F("Connection: close"));  // the connection will be closed after completion of the response
          client.println(F("Refresh: 5"));  // refresh the page automatically every 5 sec
          client.println();

           client.write(index_html, index_html_len);

           client.println();
          Serial.println("Stop response!");

          // client.flush();
          break;
        }
        if (c == '\n') {
          // you're starting a new line
          currentLineIsBlank = true;
        } else if (c != '\r') {
          // you've gotten a character on the current line
          currentLineIsBlank = false;
        }
      }
    }
    // give the web browser time to receive the data
    delay(1);

    // close the connection:
    client.stop();
    // server.flush();
    Serial.println("client disconnected");
    delay(1000);
  }
}

void printWifiStatus() {
  // print the SSID of the network you're attached to:
  Serial.print("SSID: ");
  Serial.println(WiFi.SSID());

  // print your board's IP address:
  IPAddress ip = WiFi.localIP();
  Serial.print("IP Address: ");
  Serial.println(ip);

  // print the received signal strength:
  long rssi = WiFi.RSSI();
  Serial.print("signal strength (RSSI):");
  Serial.print(rssi);
  Serial.println(" dBm");
}

And here is the web page in the browser.