+ if (!_ao_usart_tx_start(usart))
+ usart->reg->cr1 &= ~(1<< STM_USART_CR1_TXEIE);
+ }
+ if (sr & (1 << STM_USART_SR_TC)) {
+ usart->tx_running = 0;
+ usart->reg->cr1 &= ~(1 << STM_USART_CR1_TCIE);
+ if (usart->draining) {
+ usart->draining = 0;
+ ao_wakeup(&usart->tx_fifo);
+ }
+ }
+}
+
+int
+_ao_usart_pollchar(struct ao_stm_usart *usart)
+{
+ int c;
+
+ if (ao_fifo_empty(usart->rx_fifo))
+ c = AO_READ_AGAIN;
+ else {
+ uint8_t u;
+ ao_fifo_remove(usart->rx_fifo,u);
+ c = u;
+ ao_usb_putchar(c); ao_usb_flush();