HC05 Bluetooth Module Interfacing With STM32F401CCU

The HC-05 is a very easy-to-use Bluetooth to serial converter. HC-05 connects microcontrollers (like Arduino, STM32) to other Bluetooth-enabled devices. This allows the devices to communicate wirelessly with each other.HC-05 is a Bluetooth SPP (Serial Port Protocol) module designed for wireless communication. It can also be operated as a master or slave configuration.

1.STM32F401CCU Black Pill

2.HC05 Bluetooth Module

3.Jumper wire

NOTE: I've used Black Pill in my case but used a Blue Pill to show the wiring diagram because there was no Black Pill available in fritzing. Wiring will be the same for both boards.

HardwareSerial Serial1(PA10, PA9);
const int pinout = PA0; // declare pinout with int data type and pin value
char inputdata = 0;  //Variable for storing received data

void setup()
{
    Serial1.begin(9600);                      //Sets the baud rate for bluetooth pins                      
    pinMode(pinout, OUTPUT);                  //Sets digital pin PA0 as output pin for led
}

void loop()
{
   if(Serial1.available() > 0)      // Send data only when you receive data:
   {
      inputdata = Serial1.read();        //Read the incoming data & store into data
           
      if(inputdata == '1') 
      {
         digitalWrite(pinout, HIGH); 
         Serial1.print("LED ON\n");
      }
         
      else if(inputdata == '0')  
      {      
         digitalWrite(pinout, LOW);  
         Serial1.print("LED OFF\n");  
      }
   }
}

The link for the application is given below:

https://play.google.com/store/apps/details?id=de.kai_morich.serial_bluetooth_terminal&hl=en_IN&gl=US

Writing "1" in the app will turn ON the LED and writing "0" will turn OFF the LED.