Bluetooth module-Data reading (USART)

Bluetooth module-Data reading (USART)Hardware connectionControl principleMaster-slave modeHost modeSlave modeSoftware configurationPin definitionSoftware codeControl functionExperimental phenomenon

The tutorial combines the Bluetooth module to demonstrate multi-serial communication.


Serial port 5 receives the data sent by the Bluetooth module and outputs it through serial port 1
The tutorial only introduces the standard library project code

Hardware connection

Install the Bluetooth module to the corresponding interface:

Bluetooth module	Development board
VCC	VCC
TXD	RXD5
RXD	TXD5
GND	GND

Control principle

The mobile phone is paired with the Bluetooth module (slave) on the balance car through the built-in Bluetooth (host). The Bluetooth module receives the data of the balance car APP and sends it to the development board for analysis.


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The Bluetooth module sends the data transmitted by the mobile phone APP to the development board through TXD. The development board then parses the received data and obtains the corresponding command data. Later, the movement state of the car can be controlled according to this command data.

Master-slave mode

The host is responsible for managing the communication process and controlling data transmission, while the slave performs corresponding operations according to the host's instructions.

Host mode

The controller in Bluetooth communication is responsible for initiating connection requests and controlling the entire communication process.

Slave mode

Passively wait for the host's connection request and accept the host's control.

Software configuration

Pin definition

Main control chip	Pin	Main function (after reset)	Default multiplexing function	Redefine function
STM32F103RCT6	PD2	PD2	TIM3_ETR/USART5_RX/SDIO_CMD
STM32F103RCT6	PC12	PC12	USART5_TX/SDIO_CK	USART3_CK

Software code

Since the default function of the pin is the ordinary IO pin function, we need to use the default multiplexing function.


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Product supporting data source code path: Attachment → Source code summary → 2.Extended_Course → 6.Bluetooth

Control function

The tutorial only briefly introduces the code, and you can open the project source code to read it in detail.

uart_init


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void uart_init(u32 bound)
{
    //GPIO port settings
    GPIO_InitTypeDef GPIO_InitStructure;
    USART_InitTypeDef USART_InitStructure;
    NVIC_InitTypeDef NVIC_InitStructure;

    RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1|RCC_APB2Periph_GPIOA, ENABLE); //Enable USART1, GPIOA clock

    //USART1_TX GPIOA.9
    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9; //PA.9
    GPIO_InitStructure.GPIO_Speed ••= GPIO_Speed_50MHz;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP; //Multiplex push-pull output
    GPIO_Init(GPIOA, &GPIO_InitStructure);//Initialize GPIOA.9

    //USART1_RX GPIOA.10 initialization
    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10;//PA10
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;//Floating input
    GPIO_Init(GPIOA, &GPIO_InitStructure);//Initialize GPIOA.10
    //USART initialization settings

    USART_InitStructure.USART_BaudRate = bound;//Serial port baud rate
    USART_InitStructure.USART_WordLength = USART_WordLength_8b;//Word length is 8-bit data format
    USART_InitStructure.USART_StopBits = USART_StopBits_1;//One stop bit
    USART_InitStructure.USART_Parity = USART_Parity_No;//No parity bit
    USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;//No hardware data flow control
    USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx; //Transmit and receive mode

    USART_Init(USART1, &USART_InitStructure); //Initialize serial port 1
    USART_ITConfig(USART1, USART_IT_RXNE, DISABLE);//Disable serial port receive interrupt
    USART_Cmd(USART1, ENABLE); //Enable serial port 1

    NVIC_InitStructure.NVIC_IRQChannel = USART1_IRQn;
    NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
    NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1; NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; 
    NVIC_Init(&NVIC_InitStructure);
}

USART1_Send_U8


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void USART1_Send_U8(uint8_t ch)
{
    while (USART_GetFlagStatus(USART1, USART_FLAG_TXE) == RESET)
        ;
    USART_SendData(USART1, ch);
}

USART1_Send_ArrayU8


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void USART1_Send_ArrayU8(uint8_t *BufferPtr, uint16_t Length)
{
    while (Length--)
    {
        USART1_Send_U8(*BufferPtr);
        BufferPtr++;
    }
}

USART1_IRQHandler


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void USART1_IRQHandler(void)
{
    uint8_t Rx1_Temp = 0;
    if (USART_GetITStatus(USART1, USART_IT_RXNE) != RESET)
    {
        Rx1_Temp = USART_ReceiveData(USART1);
        USART1_Send_U8(Rx1_Temp);
    }
}

bluetooth_init


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void bluetooth_init(void)
{
    GPIO_InitTypeDef GPIO_InitStructure;
    USART_InitTypeDef USART_InitStructure;
    NVIC_InitTypeDef NVIC_InitStructure; 
    
    
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_UART5, ENABLE);
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOC | RCC_APB2Periph_GPIOD , ENABLE);
    
    
    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_12;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(GPIOC, &GPIO_InitStructure);    

    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_2;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
    GPIO_Init(GPIOD, &GPIO_InitStructure);
    
    
    NVIC_InitStructure.NVIC_IRQChannel = UART5_IRQn;
    NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
    NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;
    NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
    NVIC_Init(&NVIC_InitStructure);
      
    USART_InitStructure.USART_BaudRate = 9600;
    USART_InitStructure.USART_WordLength = USART_WordLength_8b;
    USART_InitStructure.USART_StopBits = USART_StopBits_1;
    USART_InitStructure.USART_Parity = USART_Parity_No ;
    USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;
    USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;
    USART_Init(UART5, &USART_InitStructure); 
//  USART_ITConfig(UART5, USART_IT_TXE, DISABLE);  

    USART_ITConfig(UART5, USART_IT_RXNE, ENABLE);   
    USART_Cmd(UART5, ENABLE);
}

UART5_Send_U8


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void UART5_Send_U8(uint8_t ch)
{
    while (USART_GetFlagStatus(UART5, USART_FLAG_TXE) == RESET)
        ;
    USART_SendData(UART5, ch);
}

UART5_Send_ArrayU8


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void UART5_Send_ArrayU8(uint8_t *BufferPtr, uint16_t Length)
{
    while (Length--)
    {
        UART5_Send_U8(*BufferPtr);
        BufferPtr++;
    }
}

UART5_IRQHandler


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void UART5_IRQHandler(void)
{
    uint8_t Rx5_Temp;
    if (USART_GetITStatus(UART5, USART_IT_RXNE) != RESET)
    {
        Rx5_Temp = USART_ReceiveData(UART5);
        USART1_Send_U8(Rx5_Temp);
    }
}

Experimental phenomenon

The Bluetooth.hex file generated by the project compilation is located in the OBJ folder of the Bluetooth project. Find the Bluetooth.hex file corresponding to the project and use the FlyMcu software to download the program into the development board.

After the program is successfully downloaded: the LED will flash. After connecting to Bluetooth using the APP, click the control button in the APP, and the development board serial port will print the corresponding command information.