Read a character from the UART

Forum|Forum|5 years ago
January 24, 2021
4 replies
3422 views

I want to read one character from the UAR and display it.

I am using CoolTerm.

But nothing is displayed.

What's wrong with my getchar function?

Or is the code in the while loop wrong?

char getchar() {
 char data[1];
 HAL_UART_Receive(&huart2, (void*)data, 1, HAL_MAX_DELAY);
 return data[0];
}
 
while (1)
 {
 HAL_UART_Transmit(&huart2,(uint8_t *) "Test",4,HAL_MAX_DELAY);
 HAL_UART_Transmit(&huart2,(uint8_t *) getchar(),1,HAL_MAX_DELAY);
 }

UART-USART

This topic has been closed for replies.

Vangelis Fortounas

Associate II

Hello

getchar returns char type and in second transmit function is interpeted as pointer to char (uint8_t*)

To echo back a charater came from coolterm use this code

uint8_t data;

while (1)

{

HAL_UART_Receive(&huart2, &data, 1, HAL_MAX_DELAY);

HAL_UART_Transmit(&huart2, &data,1,100);// dont wait too much for transmitting

}

FLamb.2Author

Associate II

No idea whether the HAL_UART_Receive is blocking or not.

I don't know what the blocking means either.

So, my current code looks like this, and it still doesn't work.

See attachement.

void getchar() {
 uint8_t data;
 HAL_UART_Receive(&huart2, &data, 1, 100);
 HAL_UART_Transmit(&huart2, &data,1,100);
}
 
 while (1)
 {
 uprints("Test\n");
 getchar();
 }