UART WITH STM32L476

Forum|Forum|3 years ago
December 6, 2022
4 replies
2985 views

i was planning to do an experiment i need to insert two numbers and calculate the sum of that two inserted number. Then i need to see them in terminal. However i have confused a bit. Could anyone help me? I get stuck over here.

/* USER CODE END 2 */

int First_Digit;

int Second_Digit;

int Sum_Digits;

/* Infinite loop */

/* USER CODE BEGIN WHILE */

while (1)

{

/* USER CODE END WHILE */

uint8_t First_Digit[] = "first digit \r\n"; // data to send

HAL_UART_Transmit(&huart2, First_Digit, 18, 100);

HAL_Delay(2000);

uint8_t Second_Digit[] = "second digit \r\n"; // data to send

HAL_UART_Transmit(&huart2, Second_Digit, 18, 100);

HAL_Delay(2000);

uint8_t Sum_Digits[] = "sum \r\n"; // data to send

HAL_UART_Transmit(&huart2, Sum_Digits, 12, 100);

HAL_Delay(2000);

/* USER CODE BEGIN 3 */

}

/* USER CODE END 3 */

}

This topic has been closed for replies.

Bob S

Super User

"experiment" == "homework" ? :)

First thing, do not hard-code string lengths into HAL_UART_Transmit() calls. Use strlen() (**NOT** sizeof()) instead:

HAL_UART_Transmit(&huart2, First_Digit, strlen(First_Digit), 100);

So how are you stuck? What is your program doing that you don't expect? Or what is it NOT doing that you want it to do?

ACekm.1Author

Associate

i can not printed the sum of two numbers. i can print first digit, second digit. however i can not be able to print sum and dont know how to make calculation in uart

Tesla DeLorean

Guru

You'll need to receiver characters, and perhaps a RETURN/ENTER character to mark the end of the input, and then convert those characters into a numeric form you can do math on.

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ACekm.1Author

Associate

could u explain me more please if u check i have also posted full code that i have developed.

Tesla DeLorean

Guru

Make sure to NUL terminate input you are feeding to string functions.

Perhaps also watch the values returned by functions, and buffer length

int read_inputs(void)
{
 char buffer[255];
 int i=0;
 
 while(1)
 {
 char button_pressed;
 if (HAL_UART_Receive(&huart2, &button_pressed, 1, 100000000) == HAL_OK)
 {
 HAL_UART_Transmit(&huart2, &button_pressed, 1, 100000000);
 if ((button_pressed == '/r') || (button_pressed == '/n') || (i >= (sizeof(buffer) - 2)))
 break;
 buffer[i++] = button_pressed;
 }
 }
 
 buffer[i++] = 0; // NUL terminate
 
 return atoi(buffer);
}

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