Get one character from the USART

[FLamb.2]

I want to get one character at position x from the USART.

Here is my current code:

What do I have to do differently?

char *getchar(int position){
	char data[1];
	data[0]=HAL_UART_Receive_IT(&huart2, data, 1);
	return data;
}

[Peter BENSCH]

The USART would receive characters serially, i.e. one after the other.

What do you mean with position x?

/Peter

[FLamb.2]

I mean, that the first character of the USART is at position 1, the second character is at position 2 etc.

 If on the USART is the text "abc" displayed then a is on position 1.

[TDK]

You have to receive characters as they come in, one by one. You can't skip ahead without losing information.

If you want, you could read them into a buffer and then use that buffer to read out values in whatever position you like.

[FLamb.2]

How can I do it?

[Pavel A.]

char getchar() {
	char data[1];
	HAL_UART_Receive(&huart2, (void*)data, 1, HAL_MAX_DELAY);
	return data[0];
}

[Tesla DeLorean]

The interrupt version completes with a callback, returning immediately, but not with data.

You can't use a local/auto variable to store the character in this fashion.

You've either got to do some buffer management via the interrupt/callback, or use the non-IT version which blocks, and might miss things if you aren't listening at the right time.

[FLamb.2]

@Community member​ 

@Pavel A.​ has the right solution?

[Tesla DeLorean]

Depends.

The polling/blocking solution falls over if you want concurrent full-duplex or multi-UART functionality. ​

[FLamb.2]

This solution doesn't work. I get strange characters. See attachement