Hal library operation STM32 serial port

This blog knowledge comes from Mr. Wei Dongshan's 7 Internet of things course .

One 、cubeMX Generate engineering framework

First select the serial port from the left 1, Then select asynchronous communication .

Two 、 analysis program

Here's the picture ,cubeMX The serial port initialization function is automatically generated .

3、 ... and 、 Programming

         After the above initialization , You can use HAL Library provides the “ HAL_UART_Transmit()” Send data from serial port , Use “ HAL_UART_Receive()” receive data , But it is inconvenient to use this way , You need to handle the data types yourself . I'm learning C Language , Usually use printf Format and print the data , It's more convenient . therefore , Here you need to redirect the print function , In the use of printf Called when the “ HAL_UART_Transmit()” Print .

printf and scanf Will call... Separately “ fputc()” and “ fgetc()”, So here we override these two functions , Use HAL The function provided realizes sending and receiving data .

        Put the following code into usart.c in , Remember to add header file #include <stdio.h>.

        printf and scanf Will call... Separately “ fputc()” and “ fgetc()”, So here we override these two functions , Use HAL The function provided realizes sending and receiving data .
 

usart.c

#pragma import(__use_no_semihosting)
struct __FILE
{
    int a;
};
FILE __stdout;
FILE __stdin;
void _sys_exit(int x)
{
        
}
/*****************************************************
*function:  Write character file function 
*param1:  Output characters 
*param2:  The file pointer 
*return:  The output character of  ASCII  code 
******************************************************/
int fputc(int ch, FILE *f)
{
    HAL_UART_Transmit(&huart1, (uint8_t*)&ch, 1, 10);
    return ch;
}
/*****************************************************
*function:  Read character file function 
*param1:  The file pointer 
*return:  Read characters  ASCII  code 
******************************************************/
int fgetc(FILE *f)
{
    uint8_t ch = 0;
    HAL_UART_Receive(&huart1, (uint8_t*)&ch, 1, 10);
    return (int)ch;
}

Write the following code in the main function

    #include <stdio.h>    

    printf(" Baiwen Technology  www.100ask.net\n\r");
    printf("UART  experiment \n\r");
    printf("test char = %c,%c\n\r", 'H', 'c');
    printf("test string1 = %s\n\r", "www.100ask.net");
    printf("test string2 = %s\n\r", " Shenzhen Baiwen Technology Co., Ltd ");
    printf("test decimal1 number = %d\n\r", 123456);
    printf("test decimal2 number = %d\n\r", -123456);
    printf("test hex1 number = 0x%x\n\r", 0x123456);
    printf("test hex2 number = 0x%08x\n\r", 0x123456);
    printf("test float = %.5f\n\r", 3.1415);
    printf("test double = %.10lf\n\r", 3.141592653);

Four 、 Effect validation

         open MobaXterm Follow these steps

The final result