Posted on May 17, 2011 at 13:18Well... here it is, the idea is that for TX it reads bytes from circ buf, and disables TXEIE when buf is empty.
usart_irqhandler is only called from the three IRQ hooks below.
From experimenting I've done, it seems it might be related to inexact baudrate.
Code:
void usart_irqhandler(enum usart_id usart_id)
{
struct usart_data *usart = &usarts[usart_id];
USART_TypeDef *usart_dev = usart->usart_dev;
usart->irqs++;
if (USART_GetITStatus(usart_dev, USART_IT_TXE)) {
unsigned char *data;
int len;
usart->irqs_tx++;
if ((data = circ_buf_get_bytes_start(usart->txbuf, &len)) &&
(usart_id != USART_RFCOMM || gpio_get_value(CB_RTS) == 0)) { /* this clears TXE */
USART_SendData(usart_dev, *data);
circ_buf_get_bytes_final(usart->txbuf, 1);
} else {
USART_ITConfig(usart_dev, USART_IT_TXE, DISABLE);
}
} else if (USART_GetITStatus(usart_dev, USART_IT_RXNE)) {
int c = USART_ReceiveData(usart_dev);
if (circ_buf_put_bytes(usart->rxbuf, (unsigned char *)&c, 1))
usart->ovf_rx++;
if (usart_id == USART_RFCOMM) /* CTS handling */
if (circ_buf_free(usart->rxbuf) == 0)
gpio_set_value(CB_CTS, 1);
}
}
void USART1_IRQHandler()
{
usart_irqhandler(USART_ID_1);
}
void USART2_IRQHandler()
{
usart_irqhandler(USART_ID_2);
}
void USART3_IRQHandler()
{
usart_irqhandler(USART_ID_3);
}
