Documentation for uart interrupts

[maciekish]

Hi,
I need to port some uart code that uses interrupts from the old libmaple core, but I cannot find any documentation regarding uart and interrupts in this core. Where do I start?

Thanks
Maciej

[fpistm]

Uart IT is used behind the scene. You could have look to HardwareSerial files.

Arduino_Core_STM32/cores/arduino/HardwareSerial.cpp

Lines 332 to 373 in 4fab426

	void HardwareSerial::_rx_complete_irq(serial_t *obj)
	{
	// No Parity error, read byte and store it in the buffer if there is room
	unsigned char c;
	if (uart_getc(obj, &c) == 0) {
	rx_buffer_index_t i = (unsigned int)(obj->rx_head + 1) % SERIAL_RX_BUFFER_SIZE;
	// if we should be storing the received character into the location
	// just before the tail (meaning that the head would advance to the
	// current location of the tail), we're about to overflow the buffer
	// and so we don't write the character or advance the head.
	if (i != obj->rx_tail) {
	obj->rx_buff[obj->rx_head] = c;
	obj->rx_head = i;
	}
	}
	}
	// Actual interrupt handlers //////////////////////////////////////////////////
	int HardwareSerial::_tx_complete_irq(serial_t *obj)
	{
	size_t remaining_data;
	// previous HAL transfer is finished, move tail pointer accordingly
	obj->tx_tail = (obj->tx_tail + obj->tx_size) % SERIAL_TX_BUFFER_SIZE;
	// If buffer is not empty (head != tail), send remaining data
	if (obj->tx_head != obj->tx_tail) {
	remaining_data = (SERIAL_TX_BUFFER_SIZE + obj->tx_head - obj->tx_tail)
	% SERIAL_TX_BUFFER_SIZE;
	// Limit the next transmission to the buffer end
	// because HAL is not able to manage rollover
	obj->tx_size = min(remaining_data,
	(size_t)(SERIAL_TX_BUFFER_SIZE - obj->tx_tail));
	uart_attach_tx_callback(obj, _tx_complete_irq, obj->tx_size);
	return -1;
	}
	return 0;
	}

Arduino_Core_STM32/libraries/SrcWrapper/src/stm32/uart.c

Lines 801 to 844 in 4fab426

	void uart_attach_rx_callback(serial_t *obj, void (*callback)(serial_t *))
	{
	if (obj == NULL) {
	return;
	}
	/* Exit if a reception is already on-going */
	if (serial_rx_active(obj)) {
	return;
	}
	obj->rx_callback = callback;
	/* Must disable interrupt to prevent handle lock contention */
	HAL_NVIC_DisableIRQ(obj->irq);
	HAL_UART_Receive_IT(uart_handlers[obj->index], &(obj->recv), 1);
	/* Enable interrupt */
	HAL_NVIC_EnableIRQ(obj->irq);
	}
	/**
	* Begin asynchronous TX transfer.
	*
	* @param obj : pointer to serial_t structure
	* @param callback : function call at the end of transmission
	* @retval none
	*/
	void uart_attach_tx_callback(serial_t *obj, int (*callback)(serial_t *), size_t size)
	{
	if (obj == NULL) {
	return;
	}
	obj->tx_callback = callback;
	/* Must disable interrupt to prevent handle lock contention */
	HAL_NVIC_DisableIRQ(obj->irq);
	/* The following function will enable UART_IT_TXE and error interrupts */
	HAL_UART_Transmit_IT(uart_handlers[obj->index], &obj->tx_buff[obj->tx_tail], size);
	/* Enable interrupt */
	HAL_NVIC_EnableIRQ(obj->irq);
	}